diff -urpN -X dontdiff linux-2.6.7/Documentation/filesystems/relayfs.txt linux-2.6.7.relayfs/Documentation/filesystems/relayfs.txt --- linux-2.6.7/Documentation/filesystems/relayfs.txt 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/Documentation/filesystems/relayfs.txt 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,812 @@ + +relayfs - a high-speed data relay filesystem +============================================ + +relayfs is a filesystem designed to provide an efficient mechanism for +tools and facilities to relay large amounts of data from kernel space +to user space. + +The main idea behind relayfs is that every data flow is put into a +separate "channel" and each channel is a file. In practice, each +channel is a separate memory buffer allocated from within kernel space +upon channel instantiation. Software needing to relay data to user +space would open a channel or a number of channels, depending on its +needs, and would log data to that channel. All the buffering and +locking mechanics are taken care of by relayfs. The actual format and +protocol used for each channel is up to relayfs' clients. + +relayfs makes no provisions for copying the same data to more than a +single channel. This is for the clients of the relay to take care of, +and so is any form of data filtering. The purpose is to keep relayfs +as simple as possible. + + +Usage +===== + +In addition to the relayfs kernel API described below, relayfs +implements basic file operations. Here are the file operations that +are available and some comments regarding their behavior: + +open() enables user to open an _existing_ channel. A channel can be + opened in blocking or non-blocking mode, and can be opened + for reading as well as for writing. Readers will by default + be auto-consuming. + +mmap() results in channel's memory buffer being mmapped into the + caller's memory space. + +read() since we are dealing with circular buffers, the user is only + allowed to read forward. Some apps may want to loop around + read() waiting for incoming data - if there is no data + available, read will put the reader on a wait queue until + data is available (blocking mode). Non-blocking reads return + -EAGAIN if data is not available. + + +write() writing from user space operates exactly as relay_write() does + (described below). + +poll() POLLIN/POLLRDNORM/POLLOUT/POLLWRNORM/POLLERR supported. + +close() decrements the channel's refcount. When the refcount reaches + 0 i.e. when no process or kernel client has the file open + (see relay_close() below), the channel buffer is freed. + + +In order for a user application to make use of relayfs files, the +relayfs filesystem must be mounted. For example, + + mount -t relayfs relayfs /mountpoint + + +The relayfs kernel API +====================== + +relayfs channels are implemented as circular buffers subdivided into +'sub-buffers'. kernel clients write data into the channel using +relay_write(), and are notified via a set of callbacks when +significant events occur within the channel. 'Significant events' +include: + +- a sub-buffer has been filled i.e. the current write won't fit into the + current sub-buffer, and a 'buffer-switch' is triggered, after which + the data is written into the next buffer (if the next buffer is + empty). The client is notified of this condition via two callbacks, + one providing an opportunity to perform start-of-buffer tasks, the + other end-of-buffer tasks. + +- data is ready for the client to process. The client can choose to + be notified either on a per-sub-buffer basis (bulk delivery) or + per-write basis (packet delivery). + +- data has been written to the channel from user space. The client can + use this notification to accept and process 'commands' sent to the + channel via write(2). + +- the channel has been opened/closed/mapped/unmapped from user space. + The client can use this notification to trigger actions within the + kernel application, such as enabling/disabling logging to the + channel. It can also return result codes from the callback, + indicating that the operation should fail e.g. in order to restrict + more than one user space open or mmap. + +- the channel needs resizing, or needs to update its + state based on the results of the resize. Resizing the channel is + up to the kernel client to actually perform. If the channel is + configured for resizing, the client is notified when the unread data + in the channel passes a preset threshold, giving it the opportunity + to allocate a new channel buffer and replace the old one. + +Reader objects +-------------- + +Channel readers use an opaque rchan_reader object to read from +channels. For VFS readers (those using read(2) to read from a +channel), these objects are automatically created and used internally; +only kernel clients that need to directly read from channels, or whose +userspace applications use mmap to access channel data, need to know +anything about rchan_readers - others may skip this section. + +A relay channel can have any number of readers, each represented by an +rchan_reader instance, which is used to encapsulate reader settings +and state. rchan_reader objects should be treated as opaque by kernel +clients. To create a reader object for directly accessing a channel +from kernel space, call the add_rchan_reader() kernel API function: + +rchan_reader *add_rchan_reader(rchan_id, auto_consume) + +This function returns an rchan_reader instance if successful, which +should then be passed to relay_read() when the kernel client is +interested in reading from the channel. + +The auto_consume parameter indicates whether a read done by this +reader will automatically 'consume' that portion of the unread channel +buffer when relay_read() is called (see below for more details). + +To close the reader, call + +remove_rchan_reader(reader) + +which will remove the reader from the list of current readers. + + +To create a reader object representing a userspace mmap reader in the +kernel application, call the add_map_reader() kernel API function: + +rchan_reader *add_map_reader(rchan_id) + +This function returns an rchan_reader instance if successful, whose +main purpose is as an argument to be passed into +relay_buffers_consumed() when the kernel client becomes aware that +data has been read by a user application using mmap to read from the +channel buffer. There is no auto_consume option in this case, since +only the kernel client/user application knows when data has been read. + +To close the map reader, call + +remove_map_reader(reader) + +which will remove the reader from the list of current readers. + +Consumed count +-------------- + +A relayfs channel is a circular buffer, which means that if there is +no reader reading from it or a reader reading too slowly, at some +point the channel writer will 'lap' the reader and data will be lost. +In normal use, readers will always be able to keep up with writers and +the buffer is thus never in danger of becoming full. In many +applications, it's sufficient to ensure that this is practically +speaking always the case, by making the buffers large enough. These +types of applications can basically open the channel as +RELAY_MODE_CONTINOUS (the default anyway) and not worry about the +meaning of 'consume' and skip the rest of this section. + +If it's important for the application that a kernel client never allow +writers to overwrite unread data, the channel should be opened using +RELAY_MODE_NO_OVERWRITE and must be kept apprised of the count of +bytes actually read by the (typically) user-space channel readers. +This count is referred to as the 'consumed count'. read(2) channel +readers automatically update the channel's 'consumed count' as they +read. If the usage mode is to have only read(2) readers, which is +typically the case, the kernel client doesn't need to worry about any +of the relayfs functions having to do with 'bytes consumed' and can +skip the rest of this section. (Note that it is possible to have +multiple read(2) or auto-consuming readers, but like having multiple +readers on a pipe, these readers will race with each other i.e. it's +supported, but doesn't make much sense). + +If the kernel client cannot rely on an auto-consuming reader to keep +the 'consumed count' up-to-date, then it must do so manually, by +making the appropriate calls to relay_buffers_consumed() or +relay_bytes_consumed(). In most cases, this should only be necessary +for bulk mmap clients - almost all packet clients should be covered by +having auto-consuming read(2) readers. For mmapped bulk clients, for +instance, there are no auto-consuming VFS readers, so the kernel +client needs to make the call to relay_buffers_consumed() after +sub-buffers are read. + +Kernel API +---------- + +Here's a summary of the API relayfs provides to in-kernel clients: + +int relay_open(channel_path, bufsize, nbufs, channel_flags, + channel_callbacks, start_reserve, end_reserve, + rchan_start_reserve, resize_min, resize_max, mode, + init_buf, init_buf_size) +int relay_write(channel_id, *data_ptr, count, time_delta_offset, **wrote) +rchan_reader *add_rchan_reader(channel_id, auto_consume) +int remove_rchan_reader(rchan_reader *reader) +rchan_reader *add_map_reader(channel_id) +int remove_map_reader(rchan_reader *reader) +int relay_read(reader, buf, count, wait, *actual_read_offset) +void relay_buffers_consumed(reader, buffers_consumed) +void relay_bytes_consumed(reader, bytes_consumed, read_offset) +int relay_bytes_avail(reader) +int rchan_full(reader) +int rchan_empty(reader) +int relay_info(channel_id, *channel_info) +int relay_close(channel_id) +int relay_realloc_buffer(channel_id, nbufs, async) +int relay_replace_buffer(channel_id) +int relay_reset(int rchan_id) + +---------- +int relay_open(channel_path, bufsize, nbufs, + channel_flags, channel_callbacks, start_reserve, + end_reserve, rchan_start_reserve, resize_min, resize_max, mode) + +relay_open() is used to create a new entry in relayfs. This new entry +is created according to channel_path. channel_path contains the +absolute path to the channel file on relayfs. If, for example, the +caller sets channel_path to "/xlog/9", a "xlog/9" entry will appear +within relayfs automatically and the "xlog" directory will be created +in the filesystem's root. relayfs does not implement any policy on +its content, except to disallow the opening of two channels using the +same file. There are, nevertheless a set of guidelines for using +relayfs. Basically, each facility using relayfs should use a top-level +directory identifying it. The entry created above, for example, +presumably belongs to the "xlog" software. + +The remaining parameters for relay_open() are as follows: + +- channel_flags - an ORed combination of attribute values controlling + common channel characteristics: + + - logging scheme - relayfs use 2 mutually exclusive schemes + for logging data to a channel. The 'lockless scheme' + reserves and writes data to a channel without the need of + any type of locking on the channel. This is the preferred + scheme, but may not be available on a given architecture (it + relies on the presence of a cmpxchg instruction). It's + specified by the RELAY_SCHEME_LOCKLESS flag. The 'locking + scheme' either obtains a lock on the channel for writing or + disables interrupts, depending on whether the channel was + opened for SMP or global usage (see below). It's specified + by the RELAY_SCHEME_LOCKING flag. While a client may want + to explicitly specify a particular scheme to use, it's more + convenient to specify RELAY_SCHEME_ANY for this flag, which + will allow relayfs to choose the best available scheme i.e. + lockless if supported. + + - overwrite mode (default is RELAY_MODE_CONTINUOUS) - + If RELAY_MODE_CONTINUOUS is specified, writes to the channel + will succeed regardless of whether there are up-to-date + consumers or not. If RELAY_MODE_NO_OVERWRITE is specified, + the channel becomes 'full' when the total amount of buffer + space unconsumed by readers equals or exceeds the total + buffer size. With the buffer in this state, writes to the + buffer will fail - clients need to check the return code from + relay_write() to determine if this is the case and act + accordingly - 0 or a negative value indicate the write failed. + + - SMP usage - this applies only when the locking scheme is in + use. If RELAY_USAGE_SMP is specified, it's assumed that the + channel will be used in a per-CPU fashion and consequently, + the only locking that will be done for writes is to disable + local irqs. If RELAY_USAGE_GLOBAL is specified, it's assumed + that writes to the buffer can occur within any CPU context, + and spinlock_irq_save will be used to lock the buffer. + + - delivery mode - if RELAY_DELIVERY_BULK is specified, the + client will be notified via its deliver() callback whenever a + sub-buffer has been filled. Alternatively, + RELAY_DELIVERY_PACKET will cause delivery to occur after the + completion of each write. See the description of the channel + callbacks below for more details. + + - timestamping - if RELAY_TIMESTAMP_TSC is specified and the + architecture supports it, efficient TSC 'timestamps' can be + associated with each write, otherwise more expensive + gettimeofday() timestamping is used. At the beginning of + each sub-buffer, a gettimeofday() timestamp and the current + TSC, if supported, are read, and are passed on to the client + via the buffer_start() callback. This allows correlation of + the current time with the current TSC for subsequent writes. + Each subsequent write is associated with a 'time delta', + which is either the current TSC, if the channel is using + TSCs, or the difference between the buffer_start gettimeofday + timestamp and the gettimeofday time read for the current + write. Note that relayfs never writes either a timestamp or + time delta into the buffer unless explicitly asked to (see + the description of relay_write() for details). + +- bufsize - the size of the 'sub-buffers' making up the circular channel + buffer. For the lockless scheme, this must be a power of 2. + +- nbufs - the number of 'sub-buffers' making up the circular + channel buffer. This must be a power of 2. + + The total size of the channel buffer is bufsize * nbufs rounded up + to the next kernel page size. If the lockless scheme is used, both + bufsize and nbufs must be a power of 2. If the locking scheme is + used, the bufsize can be anything and nbufs must be a power of 2. If + RELAY_SCHEME_ANY is used, the bufsize and nbufs should be a power of 2. + + NOTE: if nbufs is 1, relayfs will bypass the normal size + checks and will allocate an rvmalloced buffer of size bufsize. + This buffer will be freed when relay_close() is called, if the channel + isn't still being referenced. + +- callbacks - a table of callback functions called when events occur + within the data relay that clients need to know about: + + - int buffer_start(channel_id, current_write_pos, buffer_id, + start_time, start_tsc, using_tsc) - + + called at the beginning of a new sub-buffer, the + buffer_start() callback gives the client an opportunity to + write data into space reserved at the beginning of a + sub-buffer. The client should only write into the buffer + if it specified a value for start_reserve and/or + channel_start_reserve (see below) when the channel was + opened. In the latter case, the client can determine + whether to write its one-time rchan_start_reserve data by + examining the value of buffer_id, which will be 0 for the + first sub-buffer. The address that the client can write + to is contained in current_write_pos (the client by + definition knows how much it can write i.e. the value it + passed to relay_open() for start_reserve/ + channel_start_reserve). start_time contains the + gettimeofday() value for the start of the buffer and start + TSC contains the TSC read at the same time. The using_tsc + param indicates whether or not start_tsc is valid (it + wouldn't be if TSC timestamping isn't being used). + + The client should return the number of bytes it wrote to + the channel, 0 if none. + + - int buffer_end(channel_id, current_write_pos, end_of_buffer, + end_time, end_tsc, using_tsc) + + called at the end of a sub-buffer, the buffer_end() + callback gives the client an opportunity to perform + end-of-buffer processing. Note that the current_write_pos + is the position where the next write would occur, but + since the current write wouldn't fit (which is the trigger + for the buffer_end event), the buffer is considered full + even though there may be unused space at the end. The + end_of_buffer param pointer value can be used to determine + exactly the size of the unused space. The client should + only write into the buffer if it specified a value for + end_reserve when the channel was opened. If the client + doesn't write anything i.e. returns 0, the unused space at + the end of the sub-buffer is available via relay_info() - + this data may be needed by the client later if it needs to + process raw sub-buffers (an alternative would be to save + the unused bytes count value in end_reserve space at the + end of each sub-buffer during buffer_end processing and + read it when needed at a later time. The other + alternative would be to use read(2), which makes the + unused count invisible to the caller). end_time contains + the gettimeofday() value for the end of the buffer and end + TSC contains the TSC read at the same time. The using_tsc + param indicates whether or not end_tsc is valid (it + wouldn't be if TSC timestamping isn't being used). + + The client should return the number of bytes it wrote to + the channel, 0 if none. + + - void deliver(channel_id, from, len) + + called when data is ready for the client. This callback + is used to notify a client when a sub-buffer is complete + (in the case of bulk delivery) or a single write is + complete (packet delivery). A bulk delivery client might + wish to then signal a daemon that a sub-buffer is ready. + A packet delivery client might wish to process the packet + or send it elsewhere. The from param is a pointer to the + delivered data and len specifies how many bytes are ready. + + - void user_deliver(channel_id, from, len) + + called when data has been written to the channel from user + space. This callback is used to notify a client when a + successful write from userspace has occurred, independent + of whether bulk or packet delivery is in use. This can be + used to allow userspace programs to communicate with the + kernel client through the channel via out-of-band write(2) + 'commands' instead of via ioctls, for instance. The from + param is a pointer to the delivered data and len specifies + how many bytes are ready. Note that this callback occurs + after the bytes have been successfully written into the + channel, which means that channel readers must be able to + deal with the 'command' data which will appear in the + channel data stream just as any other userspace or + non-userspace write would. + + - int needs_resize(channel_id, resize_type, + suggested_buf_size, suggested_n_bufs) + + called when a channel's buffers are in danger of becoming + full i.e. the number of unread bytes in the channel passes + a preset threshold, or when the current capacity of a + channel's buffer is no longer needed. Also called to + notify the client when a channel's buffer has been + replaced. If resize_type is RELAY_RESIZE_EXPAND or + RELAY_RESIZE_SHRINK, the kernel client should arrange to + call relay_realloc_buffer() with the suggested buffer size + and buffer count, which will allocate (but will not + replace the old one) a new buffer of the recommended size + for the channel. When the allocation has completed, + needs_resize() is again called, this time with a + resize_type of RELAY_RESIZE_REPLACE. The kernel client + should then arrange to call relay_replace_buffer() to + actually replace the old channel buffer with the newly + allocated buffer. Finally, once the buffer replacement + has completed, needs_resize() is again called, this time + with a resize_type of RELAY_RESIZE_REPLACED, to inform the + client that the replacement is complete and additionally + confirming the current sub-buffer size and number of + sub-buffers. Note that a resize can be canceled if + relay_realloc_buffer() is called with the async param + non-zero and the resize conditions no longer hold. In + this case, the RELAY_RESIZE_REPLACED suggested number of + sub-buffers will be the same as the number of sub-buffers + that existed before the RELAY_RESIZE_SHRINK or EXPAND i.e. + values indicating that the resize didn't actually occur. + + - int fileop_notify(channel_id, struct file *filp, enum relay_fileop) + + called when a userspace file operation has occurred or + will occur on a relayfs channel file. These notifications + can be used by the kernel client to trigger actions within + the kernel client when the corresponding event occurs, + such as enabling logging only when a userspace application + opens or mmaps a relayfs file and disabling it again when + the file is closed or unmapped. The kernel client can + also return its own return value, which can affect the + outcome of file operation - returning 0 indicates that the + operation should succeed, and returning a negative value + indicates that the operation should be failed, and that + the returned value should be returned to the ultimate + caller e.g. returning -EPERM from the open fileop will + cause the open to fail with -EPERM. Among other things, + the return value can be used to restrict a relayfs file + from being opened or mmap'ed more than once. The currently + implemented fileops are: + + RELAY_FILE_OPEN - a relayfs file is being opened. Return + 0 to allow it to succeed, negative to + have it fail. A negative return value will + be passed on unmodified to the open fileop. + RELAY_FILE_CLOSE- a relayfs file is being closed. The return + value is ignored. + RELAY_FILE_MAP - a relayfs file is being mmap'ed. Return 0 + to allow it to succeed, negative to have + it fail. A negative return value will be + passed on unmodified to the mmap fileop. + RELAY_FILE_UNMAP- a relayfs file is being unmapped. The return + value is ignored. + + - void ioctl(rchan_id, cmd, arg) + + called when an ioctl call is made using a relayfs file + descriptor. The cmd and arg are passed along to this + callback unmodified for it to do as it wishes with. The + return value from this callback is used as the return value + of the ioctl call. + + If the callbacks param passed to relay_open() is NULL, a set of + default do-nothing callbacks will be defined for the channel. + Likewise, any NULL rchan_callback function contained in a non-NULL + callbacks struct will be filled in with a default callback function + that does nothing. + +- start_reserve - the number of bytes to be reserved at the start of + each sub-buffer. The client can do what it wants with this number + of bytes when the buffer_start() callback is invoked. Typically + clients would use this to write per-sub-buffer header data. + +- end_reserve - the number of bytes to be reserved at the end of each + sub-buffer. The client can do what it wants with this number of + bytes when the buffer_end() callback is invoked. Typically clients + would use this to write per-sub-buffer footer data. + +- channel_start_reserve - the number of bytes to be reserved, in + addition to start_reserve, at the beginning of the first sub-buffer + in the channel. The client can do what it wants with this number of + bytes when the buffer_start() callback is invoked. Typically + clients would use this to write per-channel header data. + +- resize_min - if set, this signifies that the channel is + auto-resizeable. The value specifies the size that the channel will + try to maintain as a normal working size, and that it won't go + below. The client makes use of the resizing callbacks and + relay_realloc_buffer() and relay_replace_buffer() to actually effect + the resize. + +- resize_max - if set, this signifies that the channel is + auto-resizeable. The value specifies the maximum size the channel + can have as a result of resizing. + +- mode - if non-zero, specifies the file permissions that will be given + to the channel file. If 0, the default rw user perms will be used. + +- init_buf - if non-NULL, rather than allocating the channel buffer, + this buffer will be used as the initial channel buffer. The kernel + API function relay_discard_init_buf() can later be used to have + relayfs allocate a normal mmappable channel buffer and switch over + to using it after copying the init_buf contents into it. Currently, + the size of init_buf must be exactly buf_size * n_bufs. The caller + is responsible for managing the init_buf memory. This feature is + typically used for init-time channel use and should normally be + specified as NULL. + +- init_buf_size - the total size of init_buf, if init_buf is specified + as non-NULL. Currently, the size of init_buf must be exactly + buf_size * n_bufs. + +Upon successful completion, relay_open() returns a channel id +to be used for all other operations with the relay. All buffers +managed by the relay are allocated using rvmalloc/rvfree to allow +for easy mmapping to user-space. + +---------- +int relay_write(channel_id, *data_ptr, count, time_delta_offset, **wrote_pos) + +relay_write() reserves space in the channel and writes count bytes of +data pointed to by data_ptr to it. Automatically performs any +necessary locking, depending on the scheme and SMP usage in effect (no +locking is done for the lockless scheme regardless of usage). It +returns the number of bytes written, or 0/negative on failure. If +time_delta_offset is >= 0, the internal time delta, the internal time +delta calculated when the slot was reserved will be written at that +offset. This is the TSC or gettimeofday() delta between the current +write and the beginning of the buffer, whichever method is being used +by the channel. Trying to write a count larger than the bufsize +specified to relay_open() (taking into account the reserved +start-of-buffer and end-of-buffer space as well) will fail. If +wrote_pos is non-NULL, it will receive the location the data was +written to, which may be needed for some applications but is not +normally interesting. Most applications should pass in NULL for this +param. + +---------- +struct rchan_reader *add_rchan_reader(int rchan_id, int auto_consume) + +add_rchan_reader creates and initializes a reader object for a +channel. An opaque rchan_reader object is returned on success, and is +passed to relay_read() when reading the channel. If the boolean +auto_consume parameter is 1, the reader is defined to be +auto-consuming. auto-consuming reader objects are automatically +created and used for VFS read(2) readers. + +---------- +void remove_rchan_reader(struct rchan_reader *reader) + +remove_rchan_reader finds and removes the given reader from the +channel. This function is used only by non-VFS read(2) readers. VFS +read(2) readers are automatically removed when the corresponding file +object is closed. + +---------- +reader add_map_reader(int rchan_id) + +Creates and initializes an rchan_reader object for channel map +readers, and is needed for updating relay_bytes/buffers_consumed() +when kernel clients become aware of the need to do so by their mmap +user clients. + +---------- +int remove_map_reader(reader) + +Finds and removes the given map reader from the channel. This function +is useful only for map readers. + +---------- +int relay_read(reader, buf, count, wait, *actual_read_offset) + +Reads count bytes from the channel, or as much as is available within +the sub-buffer currently being read. The read offset that will be +read from is the position contained within the reader object. If the +wait flag is set, buf is non-NULL, and there is nothing available, it +will wait until there is. If the wait flag is 0 and there is nothing +available, -EAGAIN is returned. If buf is NULL, the value returned is +the number of bytes that would have been read. actual_read_offset is +the value that should be passed as the read offset to +relay_bytes_consumed, needed only if the reader is not auto-consuming +and the channel is MODE_NO_OVERWRITE, but in any case, it must not be +NULL. + +---------- + +int relay_bytes_avail(reader) + +Returns the number of bytes available relative to the reader's current +read position within the corresponding sub-buffer, 0 if there is +nothing available. Note that this doesn't return the total bytes +available in the channel buffer - this is enough though to know if +anything is available, however, or how many bytes might be returned +from the next read. + +---------- +void relay_buffers_consumed(reader, buffers_consumed) + +Adds to the channel's consumed buffer count. buffers_consumed should +be the number of buffers newly consumed, not the total number +consumed. NOTE: kernel clients don't need to call this function if +the reader is auto-consuming or the channel is MODE_CONTINUOUS. + +In order for the relay to detect the 'buffers full' condition for a +channel, it must be kept up-to-date with respect to the number of +buffers consumed by the client. If the addition of the value of the +bufs_consumed param to the current bufs_consumed count for the channel +would exceed the bufs_produced count for the channel, the channel's +bufs_consumed count will be set to the bufs_produced count for the +channel. This allows clients to 'catch up' if necessary. + +---------- +void relay_bytes_consumed(reader, bytes_consumed, read_offset) + +Adds to the channel's consumed count. bytes_consumed should be the +number of bytes actually read e.g. return value of relay_read() and +the read_offset should be the actual offset the bytes were read from +e.g. the actual_read_offset set by relay_read(). NOTE: kernel clients +don't need to call this function if the reader is auto-consuming or +the channel is MODE_CONTINUOUS. + +In order for the relay to detect the 'buffers full' condition for a +channel, it must be kept up-to-date with respect to the number of +bytes consumed by the client. For packet clients, it makes more sense +to update after each read rather than after each complete sub-buffer +read. The bytes_consumed count updates bufs_consumed when a buffer +has been consumed so this count remains consistent. + +---------- +int relay_info(channel_id, *channel_info) + +relay_info() fills in an rchan_info struct with channel status and +attribute information such as usage modes, sub-buffer size and count, +the allocated size of the entire buffer, buffers produced and +consumed, current buffer id, count of writes lost due to buffers full +condition. + +The virtual address of the channel buffer is also available here, for +those clients that need it. + +Clients may need to know how many 'unused' bytes there are at the end +of a given sub-buffer. This would only be the case if the client 1) +didn't either write this count to the end of the sub-buffer or +otherwise note it (it's available as the difference between the buffer +end and current write pos params in the buffer_end callback) (if the +client returned 0 from the buffer_end callback, it's assumed that this +is indeed the case) 2) isn't using the read() system call to read the +buffer. In other words, if the client isn't annotating the stream and +is reading the buffer by mmaping it, this information would be needed +in order for the client to 'skip over' the unused bytes at the ends of +sub-buffers. + +Additionally, for the lockless scheme, clients may need to know +whether a particular sub-buffer is actually complete. An array of +boolean values, one per sub-buffer, contains non-zero if the buffer is +complete, non-zero otherwise. + +---------- +int relay_close(channel_id) + +relay_close() is used to close the channel. It finalizes the last +sub-buffer (the one currently being written to) and marks the channel +as finalized. The channel buffer and channel data structure are then +freed automatically when the last reference to the channel is given +up. + +---------- +int relay_realloc_buffer(channel_id, nbufs, async) + +Allocates a new channel buffer using the specified sub-buffer count +(note that resizing can't change sub-buffer sizes). If async is +non-zero, the allocation is done in the background using a work queue. +When the allocation has completed, the needs_resize() callback is +called with a resize_type of RELAY_RESIZE_REPLACE. This function +doesn't replace the old buffer with the new - see +relay_replace_buffer(). + +This function is called by kernel clients in response to a +needs_resize() callback call with a resize type of RELAY_RESIZE_EXPAND +or RELAY_RESIZE_SHRINK. That callback also includes a suggested +new_bufsize and new_nbufs which should be used when calling this +function. + +Returns 0 on success, or errcode if the channel is busy or if +the allocation couldn't happen for some reason. + +NOTE: if async is not set, this function should not be called with a +lock held, as it may sleep. + +---------- +int relay_replace_buffer(channel_id) + +Replaces the current channel buffer with the new buffer allocated by +relay_realloc_buffer and contained in the channel struct. When the +replacement is complete, the needs_resize() callback is called with +RELAY_RESIZE_REPLACED. This function is called by kernel clients in +response to a needs_resize() callback having a resize type of +RELAY_RESIZE_REPLACE. + +Returns 0 on success, or errcode if the channel is busy or if the +replacement or previous allocation didn't happen for some reason. + +NOTE: This function will not sleep, so can called in any context and +with locks held. The client should, however, ensure that the channel +isn't actively being read from or written to. + +---------- +int relay_reset(rchan_id) + +relay_reset() has the effect of erasing all data from the buffer and +restarting the channel in its initial state. The buffer itself is not +freed, so any mappings are still in effect. NOTE: Care should be +taken that the channnel isn't actually being used by anything when +this call is made. + +---------- +int rchan_full(reader) + +returns 1 if the channel is full with respect to the reader, 0 if not. + +---------- +int rchan_empty(reader) + +returns 1 if the channel is empty with respect to the reader, 0 if not. + +---------- +int relay_discard_init_buf(rchan_id) + +allocates an mmappable channel buffer, copies the contents of init_buf +into it, and sets the current channel buffer to the newly allocated +buffer. This function is used only in conjunction with the init_buf +and init_buf_size params to relay_open(), and is typically used when +the ability to write into the channel at init-time is needed. The +basic usage is to specify an init_buf and init_buf_size to relay_open, +then call this function when it's safe to switch over to a normally +allocated channel buffer. 'Safe' means that the caller is in a +context that can sleep and that nothing is actively writing to the +channel. Returns 0 if successful, negative otherwise. + + +Writing directly into the channel +================================= + +Using the relay_write() API function as described above is the +preferred means of writing into a channel. In some cases, however, +in-kernel clients might want to write directly into a relay channel +rather than have relay_write() copy it into the buffer on the client's +behalf. Clients wishing to do this should follow the model used to +implement relay_write itself. The general sequence is: + +- get a pointer to the channel via rchan_get(). This increments the + channel's reference count. +- call relay_lock_channel(). This will perform the proper locking for + the channel given the scheme in use and the SMP usage. +- reserve a slot in the channel via relay_reserve() +- write directly to the reserved address +- call relay_commit() to commit the write +- call relay_unlock_channel() +- call rchan_put() to release the channel reference + +In particular, clients should make sure they call rchan_get() and +rchan_put() and not hold on to references to the channel pointer. +Also, forgetting to use relay_lock_channel()/relay_unlock_channel() +has no effect if the lockless scheme is being used, but could result +in corrupted buffer contents if the locking scheme is used. + + +Limitations +=========== + +Writes made via the write() system call are currently limited to 2 +pages worth of data. There is no such limit on the in-kernel API +function relay_write(). + +User applications can currently only mmap the complete buffer (it +doesn't really make sense to mmap only part of it, given its purpose). + + +Latest version +============== + +The latest version can be found at: + +http://www.opersys.com/relayfs + +Example relayfs clients, such as dynamic printk and the Linux Trace +Toolkit, can also be found there. + + +Credits +======= + +The ideas and specs for relayfs came about as a result of discussions +on tracing involving the following: + +Michel Dagenais +Richard Moore +Bob Wisniewski +Karim Yaghmour +Tom Zanussi + +Also thanks to Hubertus Franke for a lot of useful suggestions and bug +reports, and for contributing the klog code. diff -urpN -X dontdiff linux-2.6.7/fs/Kconfig linux-2.6.7.relayfs/fs/Kconfig --- linux-2.6.7/fs/Kconfig 2004-06-16 00:19:36.000000000 -0500 +++ linux-2.6.7.relayfs/fs/Kconfig 2004-06-24 00:55:41.000000000 -0500 @@ -946,6 +946,57 @@ config RAMFS To compile this as a module, choose M here: the module will be called ramfs. +config RELAYFS_FS + tristate "Relayfs file system support" + ---help--- + Relayfs is a high-speed data relay filesystem designed to provide + an efficient mechanism for tools and facilities to relay large + amounts of data from kernel space to user space. It's not useful + on its own, and should only be enabled if other facilities that + need it are enabled, such as for example klog or the Linux Trace + Toolkit. + + See for further + information. + + This file system is also available as a module ( = code which can be + inserted in and removed from the running kernel whenever you want). + The module is called relayfs. If you want to compile it as a + module, say M here and read . + + If unsure, say N. + +config KLOG_CHANNEL + bool "Enable klog debugging support" + depends on RELAYFS_FS + default n + help + If you say Y to this, a relayfs channel named klog will be created + in the root of the relayfs file system. You can write to the klog + channel using klog() or klog_raw() from within the kernel or + kernel modules, and read from the klog channel by mounting relayfs + and using read(2) to read from it (or using cat). If you're not + sure, say N. + +config KLOG_CHANNEL_AUTOENABLE + bool "Enable klog logging on startup" + depends on KLOG_CHANNEL + default y + help + If you say Y to this, the klog channel will be automatically enabled + on startup. Otherwise, to turn klog logging on, you need use + sysctl (fs.relayfs.klog_enabled). This option is used in cases where + you don't actually want the channel to be written to until it's + enabled. If you're not sure, say Y. + +config KLOG_CHANNEL_SHIFT + depends on KLOG_CHANNEL + int "klog debugging channel size (14 => 16KB, 22 => 4MB)" + range 14 22 + default 21 + help + Select klog debugging channel size as a power of 2. + endmenu menu "Miscellaneous filesystems" @@ -1210,8 +1261,6 @@ config HPFS_FS To compile this file system support as a module, choose M here: the module will be called hpfs. If unsure, say N. - - config QNX4FS_FS tristate "QNX4 file system support (read only)" help @@ -1237,8 +1286,6 @@ config QNX4FS_RW It's currently broken, so for now: answer N. - - config SYSV_FS tristate "System V/Xenix/V7/Coherent file system support" help @@ -1275,8 +1322,6 @@ config SYSV_FS If you haven't heard about all of this before, it's safe to say N. - - config UFS_FS tristate "UFS file system support (read only)" help diff -urpN -X dontdiff linux-2.6.7/fs/Makefile linux-2.6.7.relayfs/fs/Makefile --- linux-2.6.7/fs/Makefile 2004-06-16 00:19:36.000000000 -0500 +++ linux-2.6.7.relayfs/fs/Makefile 2004-06-24 00:52:59.000000000 -0500 @@ -52,6 +52,7 @@ obj-$(CONFIG_EXT2_FS) += ext2/ obj-$(CONFIG_CRAMFS) += cramfs/ obj-$(CONFIG_RAMFS) += ramfs/ obj-$(CONFIG_HUGETLBFS) += hugetlbfs/ +obj-$(CONFIG_RELAYFS_FS) += relayfs/ obj-$(CONFIG_CODA_FS) += coda/ obj-$(CONFIG_MINIX_FS) += minix/ obj-$(CONFIG_FAT_FS) += fat/ diff -urpN -X dontdiff linux-2.6.7/fs/relayfs/Makefile linux-2.6.7.relayfs/fs/relayfs/Makefile --- linux-2.6.7/fs/relayfs/Makefile 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/fs/relayfs/Makefile 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,8 @@ +# +# relayfs Makefile +# + +obj-$(CONFIG_RELAYFS_FS) += relayfs.o + +relayfs-y := relay.o relay_lockless.o relay_locking.o inode.o resize.o +relayfs-$(CONFIG_KLOG_CHANNEL) += klog.o diff -urpN -X dontdiff linux-2.6.7/fs/relayfs/inode.c linux-2.6.7.relayfs/fs/relayfs/inode.c --- linux-2.6.7/fs/relayfs/inode.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/fs/relayfs/inode.c 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,630 @@ +/* + * VFS-related code for RelayFS, a high-speed data relay filesystem. + * + * Copyright (C) 2003 - Tom Zanussi , IBM Corp + * Copyright (C) 2003 - Karim Yaghmour + * + * Based on ramfs, Copyright (C) 2002 - Linus Torvalds + * + * This file is released under the GPL. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define RELAYFS_MAGIC 0x26F82121 + +static struct super_operations relayfs_ops; +static struct address_space_operations relayfs_aops; +static struct inode_operations relayfs_file_inode_operations; +static struct file_operations relayfs_file_operations; +static struct inode_operations relayfs_dir_inode_operations; + +static struct vfsmount * relayfs_mount; +static int relayfs_mount_count; + +static struct backing_dev_info relayfs_backing_dev_info = { + .ra_pages = 0, /* No readahead */ + .memory_backed = 1, /* Does not contribute to dirty memory */ +}; + +static struct inode * +relayfs_get_inode(struct super_block *sb, int mode, dev_t dev) +{ + struct inode * inode; + + inode = new_inode(sb); + + if (inode) { + inode->i_mode = mode; + inode->i_uid = current->fsuid; + inode->i_gid = current->fsgid; + inode->i_blksize = PAGE_CACHE_SIZE; + inode->i_blocks = 0; + inode->i_mapping->a_ops = &relayfs_aops; + inode->i_mapping->backing_dev_info = &relayfs_backing_dev_info; + inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; + switch (mode & S_IFMT) { + default: + init_special_inode(inode, mode, dev); + break; + case S_IFREG: + inode->i_op = &relayfs_file_inode_operations; + inode->i_fop = &relayfs_file_operations; + break; + case S_IFDIR: + inode->i_op = &relayfs_dir_inode_operations; + inode->i_fop = &simple_dir_operations; + + /* directory inodes start off with i_nlink == 2 (for "." entry) */ + inode->i_nlink++; + break; + case S_IFLNK: + inode->i_op = &page_symlink_inode_operations; + break; + } + } + return inode; +} + +/* + * File creation. Allocate an inode, and we're done.. + */ +/* SMP-safe */ +static int +relayfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) +{ + struct inode * inode; + int error = -ENOSPC; + + inode = relayfs_get_inode(dir->i_sb, mode, dev); + + if (inode) { + d_instantiate(dentry, inode); + dget(dentry); /* Extra count - pin the dentry in core */ + error = 0; + } + return error; +} + +static int +relayfs_mkdir(struct inode * dir, struct dentry * dentry, int mode) +{ + int retval; + + retval = relayfs_mknod(dir, dentry, mode | S_IFDIR, 0); + + if (!retval) + dir->i_nlink++; + return retval; +} + +static int +relayfs_create(struct inode *dir, struct dentry *dentry, int mode, struct nameidata *nd) +{ + return relayfs_mknod(dir, dentry, mode | S_IFREG, 0); +} + +static int +relayfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname) +{ + struct inode *inode; + int error = -ENOSPC; + + inode = relayfs_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); + + if (inode) { + int l = strlen(symname)+1; + error = page_symlink(inode, symname, l); + if (!error) { + d_instantiate(dentry, inode); + dget(dentry); + } else + iput(inode); + } + return error; +} + +/** + * relayfs_create_entry - create a relayfs directory or file + * @name: the name of the file to create + * @parent: parent directory + * @dentry: result dentry + * @entry_type: type of file to create (S_IFREG, S_IFDIR) + * @mode: mode + * @data: data to associate with the file + * + * Creates a file or directory with the specifed permissions. + */ +static int +relayfs_create_entry(const char * name, struct dentry * parent, struct dentry **dentry, int entry_type, int mode, void * data) +{ + struct qstr qname; + struct dentry * d; + + int error = 0; + + error = simple_pin_fs("relayfs", &relayfs_mount, &relayfs_mount_count); + if (error) { + printk(KERN_ERR "Couldn't mount relayfs: errcode %d\n", error); + return error; + } + + qname.name = name; + qname.len = strlen(name); + qname.hash = full_name_hash(name, qname.len); + + if (parent == NULL) + if (relayfs_mount && relayfs_mount->mnt_sb) + parent = relayfs_mount->mnt_sb->s_root; + + if (parent == NULL) { + simple_release_fs(&relayfs_mount, &relayfs_mount_count); + return -EINVAL; + } + + parent = dget(parent); + down(&parent->d_inode->i_sem); + d = lookup_hash(&qname, parent); + if (IS_ERR(d)) { + error = PTR_ERR(d); + goto release_mount; + } + + if (d->d_inode) { + error = -EEXIST; + goto release_mount; + } + + if (entry_type == S_IFREG) + error = relayfs_create(parent->d_inode, d, entry_type | mode, NULL); + else + error = relayfs_mkdir(parent->d_inode, d, entry_type | mode); + if (error) + goto release_mount; + + if ((entry_type == S_IFREG) && data) { + d->d_inode->u.generic_ip = data; + goto exit; /* don't release mount for regular files */ + } + +release_mount: + simple_release_fs(&relayfs_mount, &relayfs_mount_count); +exit: + *dentry = d; + up(&parent->d_inode->i_sem); + dput(parent); + + return error; +} + +/** + * relayfs_create_file - create a file in the relay filesystem + * @name: the name of the file to create + * @parent: parent directory + * @dentry: result dentry + * @data: data to associate with the file + * @mode: mode, if not specied the default perms are used + * + * The file will be created user rw on behalf of current user. + */ +int +relayfs_create_file(const char * name, struct dentry * parent, struct dentry **dentry, void * data, int mode) +{ + if (!mode) + mode = S_IRUSR | S_IWUSR; + + return relayfs_create_entry(name, parent, dentry, S_IFREG, + mode, data); +} + +/** + * relayfs_create_dir - create a directory in the relay filesystem + * @name: the name of the directory to create + * @parent: parent directory + * @dentry: result dentry + * + * The directory will be created world rwx on behalf of current user. + */ +int +relayfs_create_dir(const char * name, struct dentry * parent, struct dentry **dentry) +{ + return relayfs_create_entry(name, parent, dentry, S_IFDIR, + S_IRWXU | S_IRUGO | S_IXUGO, NULL); +} + +/** + * relayfs_remove_file - remove a file in the relay filesystem + * @dentry: file dentry + * + * Remove a file previously created by relayfs_create_file. + */ +int +relayfs_remove_file(struct dentry *dentry) +{ + struct dentry *parent; + int is_reg; + + parent = dentry->d_parent; + if (parent == NULL) + return -EINVAL; + + is_reg = S_ISREG(dentry->d_inode->i_mode); + + parent = dget(parent); + down(&parent->d_inode->i_sem); + if (dentry->d_inode) { + simple_unlink(parent->d_inode, dentry); + d_delete(dentry); + } + dput(dentry); + up(&parent->d_inode->i_sem); + dput(parent); + + if(is_reg) + simple_release_fs(&relayfs_mount, &relayfs_mount_count); + + return 0; +} + +/** + * relayfs_open - open file op for relayfs files + * @inode: the inode + * @filp: the file + * + * Associates the channel with the file, and increments the + * channel refcount. Reads will be 'auto-consuming'. + */ +int +relayfs_open(struct inode *inode, struct file *filp) +{ + struct rchan *rchan; + struct rchan_reader *reader; + int retval = 0; + + if (inode->u.generic_ip) { + rchan = (struct rchan *)inode->u.generic_ip; + if (rchan == NULL) + return -EACCES; + reader = __add_rchan_reader(rchan, filp, 1, 0); + if (reader == NULL) + return -ENOMEM; + filp->private_data = reader; + retval = rchan->callbacks->fileop_notify(rchan->id, filp, + RELAY_FILE_OPEN); + if (retval == 0) + /* Inc relay channel refcount for file */ + rchan_get(rchan->id); + else { + __remove_rchan_reader(reader); + retval = -EPERM; + } + } + + return retval; +} + +/** + * relayfs_mmap - mmap file op for relayfs files + * @filp: the file + * @vma: the vma describing what to map + * + * Calls upon relay_mmap_buffer to map the file into user space. + */ +int +relayfs_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct rchan *rchan; + + rchan = ((struct rchan_reader *)filp->private_data)->rchan; + + return __relay_mmap_buffer(rchan, vma); +} + +/** + * relayfs_file_read - read file op for relayfs files + * @filp: the file + * @buf: user buf to read into + * @count: bytes requested + * @offset: offset into file + * + * Reads count bytes from the channel, or as much as is available within + * the sub-buffer currently being read. Reads are 'auto-consuming'. + * See relay_read() for details. + * + * Returns bytes read on success, 0 or -EAGAIN if nothing available, + * negative otherwise. + */ +ssize_t +relayfs_file_read(struct file *filp, char * buf, size_t count, loff_t *offset) +{ + size_t read_count; + struct rchan_reader *reader; + u32 dummy; /* all VFS readers are auto-consuming */ + + if (offset != &filp->f_pos) /* pread, seeking not supported */ + return -ESPIPE; + + if (count == 0) + return 0; + + reader = (struct rchan_reader *)filp->private_data; + read_count = relay_read(reader, buf, count, + filp->f_flags & (O_NDELAY | O_NONBLOCK) ? 0 : 1, &dummy); + + return read_count; +} + +/** + * relayfs_file_write - write file op for relayfs files + * @filp: the file + * @buf: user buf to write from + * @count: bytes to write + * @offset: offset into file + * + * Reserves a slot in the relay buffer and writes count bytes + * into it. The current limit for a single write is 2 pages + * worth. The user_deliver() channel callback will be invoked on + * + * Returns bytes written on success, 0 or -EAGAIN if nothing available, + * negative otherwise. + */ +ssize_t +relayfs_file_write(struct file *filp, const char *buf, size_t count, loff_t *offset) +{ + int write_count; + char * write_buf; + struct rchan *rchan; + int err = 0; + void *wrote_pos; + struct rchan_reader *reader; + + reader = (struct rchan_reader *)filp->private_data; + if (reader == NULL) + return -EPERM; + + rchan = reader->rchan; + if (rchan == NULL) + return -EPERM; + + if (count == 0) + return 0; + + /* Change this if need to write more than 2 pages at once */ + if (count > 2 * PAGE_SIZE) + return -EINVAL; + + write_buf = (char *)__get_free_pages(GFP_KERNEL, 1); + if (write_buf == NULL) + return -ENOMEM; + + if (copy_from_user(write_buf, buf, count)) + return -EFAULT; + + if (filp->f_flags & (O_NDELAY | O_NONBLOCK)) { + write_count = relay_write(rchan->id, write_buf, count, -1, &wrote_pos); + if (write_count == 0) + return -EAGAIN; + } else { + err = wait_event_interruptible(rchan->write_wait, + (write_count = relay_write(rchan->id, write_buf, count, -1, &wrote_pos))); + if (err) + return err; + } + + free_pages((unsigned long)write_buf, 1); + + rchan->callbacks->user_deliver(rchan->id, wrote_pos, write_count); + + return write_count; +} + +/** + * relayfs_ioctl - ioctl file op for relayfs files + * @inode: the inode + * @filp: the file + * @cmd: the command + * @arg: command arg + * + * Passes the specified cmd/arg to the kernel client. arg may be a + * pointer to user-space data, in which case the kernel client is + * responsible for copying the data to/from user space appropriately. + * The kernel client is also responsible for returning a meaningful + * return value for ioctl calls. + * + * Returns result of relay channel callback, -EPERM if unsuccessful. + */ +int +relayfs_ioctl(struct inode *inode, struct file *filp, unsigned int cmd, unsigned long arg) +{ + struct rchan *rchan; + struct rchan_reader *reader; + + reader = (struct rchan_reader *)filp->private_data; + if (reader == NULL) + return -EPERM; + + rchan = reader->rchan; + if (rchan == NULL) + return -EPERM; + + return rchan->callbacks->ioctl(rchan->id, cmd, arg); +} + +/** + * relayfs_poll - poll file op for relayfs files + * @filp: the file + * @wait: poll table + * + * Poll implemention. + */ +static unsigned int +relayfs_poll(struct file *filp, poll_table *wait) +{ + struct rchan_reader *reader; + unsigned int mask = 0; + + reader = (struct rchan_reader *)filp->private_data; + + if (reader->rchan->finalized) + return POLLERR; + + if (filp->f_mode & FMODE_READ) { + poll_wait(filp, &reader->rchan->read_wait, wait); + if (!rchan_empty(reader)) + mask |= POLLIN | POLLRDNORM; + } + + if (filp->f_mode & FMODE_WRITE) { + poll_wait(filp, &reader->rchan->write_wait, wait); + if (!rchan_full(reader)) + mask |= POLLOUT | POLLWRNORM; + } + + return mask; +} + +/** + * relayfs_release - release file op for relayfs files + * @inode: the inode + * @filp: the file + * + * Decrements the channel refcount, as the filesystem is + * no longer using it. + */ +int +relayfs_release(struct inode *inode, struct file *filp) +{ + struct rchan_reader *reader; + struct rchan *rchan; + + reader = (struct rchan_reader *)filp->private_data; + if (reader == NULL || reader->rchan == NULL) + return 0; + rchan = reader->rchan; + + rchan->callbacks->fileop_notify(reader->rchan->id, filp, + RELAY_FILE_CLOSE); + __remove_rchan_reader(reader); + /* The channel is no longer in use as far as this file is concerned */ + rchan_put(rchan); + + return 0; +} + +static struct address_space_operations relayfs_aops = { + .readpage = simple_readpage, + .prepare_write = simple_prepare_write, + .commit_write = simple_commit_write +}; + +static struct file_operations relayfs_file_operations = { + .open = relayfs_open, + .llseek = no_llseek, + .read = relayfs_file_read, + .write = relayfs_file_write, + .ioctl = relayfs_ioctl, + .poll = relayfs_poll, + .mmap = relayfs_mmap, + .fsync = simple_sync_file, + .release = relayfs_release, +}; + +static struct inode_operations relayfs_file_inode_operations = { + .getattr = simple_getattr, +}; + +static struct inode_operations relayfs_dir_inode_operations = { + .create = relayfs_create, + .lookup = simple_lookup, + .link = simple_link, + .unlink = simple_unlink, + .symlink = relayfs_symlink, + .mkdir = relayfs_mkdir, + .rmdir = simple_rmdir, + .mknod = relayfs_mknod, + .rename = simple_rename, +}; + +static struct super_operations relayfs_ops = { + .statfs = simple_statfs, + .drop_inode = generic_delete_inode, +}; + +static int +relayfs_fill_super(struct super_block * sb, void * data, int silent) +{ + struct inode * inode; + struct dentry * root; + + sb->s_blocksize = PAGE_CACHE_SIZE; + sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_magic = RELAYFS_MAGIC; + sb->s_op = &relayfs_ops; + inode = relayfs_get_inode(sb, S_IFDIR | 0755, 0); + + if (!inode) + return -ENOMEM; + + root = d_alloc_root(inode); + if (!root) { + iput(inode); + return -ENOMEM; + } + sb->s_root = root; + + return 0; +} + +static struct super_block * +relayfs_get_sb(struct file_system_type *fs_type, + int flags, const char *dev_name, void *data) +{ + return get_sb_single(fs_type, flags, data, relayfs_fill_super); +} + +static struct file_system_type relayfs_fs_type = { + .owner = THIS_MODULE, + .name = "relayfs", + .get_sb = relayfs_get_sb, + .kill_sb = kill_litter_super, +}; + +static int __init +init_relayfs_fs(void) +{ + int err = register_filesystem(&relayfs_fs_type); +#ifdef CONFIG_KLOG_CHANNEL + if (!err) + create_klog_channel(); +#endif + return err; +} + +static void __exit +exit_relayfs_fs(void) +{ +#ifdef CONFIG_KLOG_CHANNEL + remove_klog_channel(); +#endif + unregister_filesystem(&relayfs_fs_type); +} + +module_init(init_relayfs_fs) +module_exit(exit_relayfs_fs) + +MODULE_AUTHOR("Tom Zanussi and Karim Yaghmour "); +MODULE_DESCRIPTION("Relay Filesystem"); +MODULE_LICENSE("GPL"); + diff -urpN -X dontdiff linux-2.6.7/fs/relayfs/klog.c linux-2.6.7.relayfs/fs/relayfs/klog.c --- linux-2.6.7/fs/relayfs/klog.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/fs/relayfs/klog.c 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,206 @@ +/* + * KLOG Generic Logging facility built upon the relayfs infrastructure + * + * Authors: Hubertus Franke (frankeh@us.ibm.com) + * Tom Zanussi (zanussi@us.ibm.com) + * + * Please direct all questions/comments to zanussi@us.ibm.com + * + * Copyright (C) 2003, IBM Corp + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +/* klog channel id */ +static int klog_channel = -1; + +/* maximum size of klog formatting buffer beyond which truncation will occur */ +#define KLOG_BUF_SIZE (512) +/* per-cpu klog formatting buffer */ +static char buf[NR_CPUS][KLOG_BUF_SIZE]; + +/* + * klog_enabled determines whether klog()/klog_raw() actually do write + * to the klog channel at any given time. If klog_enabled == 1 they do, + * otherwise they don't. Settable using sysctl fs.relayfs.klog_enabled. + */ +#ifdef CONFIG_KLOG_CHANNEL_AUTOENABLE +static int klog_enabled = 1; +#else +static int klog_enabled = 0; +#endif + +/** + * klog - write a formatted string into the klog channel + * @fmt: format string + * + * Returns number of bytes written, negative number on failure. + */ +int klog(const char *fmt, ...) +{ + va_list args; + int len, err; + char *cbuf; + unsigned long flags; + + if (!klog_enabled || klog_channel < 0) + return 0; + + local_irq_save(flags); + cbuf = buf[smp_processor_id()]; + + va_start(args, fmt); + len = vsnprintf(cbuf, KLOG_BUF_SIZE, fmt, args); + va_end(args); + + err = relay_write(klog_channel, cbuf, len, -1, NULL); + local_irq_restore(flags); + + return err; +} + +/** + * klog_raw - directly write into the klog channel + * @buf: buffer containing data to write + * @len: # bytes to write + * + * Returns number of bytes written, negative number on failure. + */ +int klog_raw(const char *buf,int len) +{ + int err = 0; + + if (klog_enabled && klog_channel >= 0) + err = relay_write(klog_channel, buf, len, -1, NULL); + + return err; +} + +/** + * relayfs sysctl data + * + * Only sys/fs/relayfs/klog_enabled for now. + */ +#define CTL_ENABLE_KLOG 100 +#define CTL_RELAYFS 100 + +static struct ctl_table_header *relayfs_ctl_table_header; + +static struct ctl_table relayfs_table[] = +{ + { + .ctl_name = CTL_ENABLE_KLOG, + .procname = "klog_enabled", + .data = &klog_enabled, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, + { + 0 + } +}; + +static struct ctl_table relayfs_dir_table[] = +{ + { + .ctl_name = CTL_RELAYFS, + .procname = "relayfs", + .data = NULL, + .maxlen = 0, + .mode = 0555, + .child = relayfs_table, + }, + { + 0 + } +}; + +static struct ctl_table relayfs_root_table[] = +{ + { + .ctl_name = CTL_FS, + .procname = "fs", + .data = NULL, + .maxlen = 0, + .mode = 0555, + .child = relayfs_dir_table, + }, + { + 0 + } +}; + +/** + * create_klog_channel - creates channel /mnt/relay/klog + * + * Returns channel id on success, negative otherwise. + */ +int +create_klog_channel(void) +{ + u32 bufsize, nbufs; + u32 channel_flags; + + channel_flags = RELAY_DELIVERY_PACKET | RELAY_USAGE_GLOBAL; + channel_flags |= RELAY_SCHEME_ANY | RELAY_TIMESTAMP_ANY; + + bufsize = 1 << (CONFIG_KLOG_CHANNEL_SHIFT - 2); + nbufs = 4; + + klog_channel = relay_open("klog", + bufsize, + nbufs, + channel_flags, + NULL, + 0, + 0, + 0, + 0, + 0, + 0, + NULL, + 0); + + if (klog_channel < 0) + printk("klog channel creation failed, errcode: %d\n", klog_channel); + else { + printk("klog channel created (%u bytes)\n", 1 << CONFIG_KLOG_CHANNEL_SHIFT); + relayfs_ctl_table_header = register_sysctl_table(relayfs_root_table, 1); + } + + return klog_channel; +} + +/** + * remove_klog_channel - destroys channel /mnt/relay/klog + * + * Returns 0, negative otherwise. + */ +int +remove_klog_channel(void) +{ + if (relayfs_ctl_table_header) + unregister_sysctl_table(relayfs_ctl_table_header); + + return relay_close(klog_channel); +} + +EXPORT_SYMBOL(klog); +EXPORT_SYMBOL(klog_raw); + diff -urpN -X dontdiff linux-2.6.7/fs/relayfs/relay.c linux-2.6.7.relayfs/fs/relayfs/relay.c --- linux-2.6.7/fs/relayfs/relay.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/fs/relayfs/relay.c 2004-06-24 00:54:29.000000000 -0500 @@ -0,0 +1,1948 @@ +/* + * Public API and common code for RelayFS. + * + * Please see Documentation/filesystems/relayfs.txt for API description. + * + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com) + * + * This file is released under the GPL. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include + +#include "relay_lockless.h" +#include "relay_locking.h" +#include "resize.h" + +/* Relay channel table, indexed by channel id */ +static struct rchan * rchan_table[RELAY_MAX_CHANNELS]; +static rwlock_t rchan_table_lock = RW_LOCK_UNLOCKED; + +/* Relay operation structs, one per scheme */ +static struct relay_ops lockless_ops = { + .reserve = lockless_reserve, + .commit = lockless_commit, + .get_offset = lockless_get_offset, + .finalize = lockless_finalize, + .reset = lockless_reset, + .reset_index = lockless_reset_index +}; + +static struct relay_ops locking_ops = { + .reserve = locking_reserve, + .commit = locking_commit, + .get_offset = locking_get_offset, + .finalize = locking_finalize, + .reset = locking_reset, + .reset_index = locking_reset_index +}; + +/* + * Low-level relayfs kernel API. These functions should not normally be + * used by clients. See high-level kernel API below. + */ + +/** + * rchan_get - get channel associated with id, incrementing refcount + * @rchan_id: the channel id + * + * Returns channel if successful, NULL otherwise. + */ +struct rchan * +rchan_get(int rchan_id) +{ + struct rchan *rchan; + + if ((rchan_id < 0) || (rchan_id >= RELAY_MAX_CHANNELS)) + return NULL; + + read_lock(&rchan_table_lock); + rchan = rchan_table[rchan_id]; + if (rchan) + atomic_inc(&rchan->refcount); + read_unlock(&rchan_table_lock); + + return rchan; +} + +/** + * clear_readers - clear non-VFS readers + * @rchan: the channel + * + * Clear the channel pointers of all non-VFS readers open on the channel. + */ +static inline void +clear_readers(struct rchan *rchan) +{ + struct list_head *p; + struct rchan_reader *reader; + + read_lock(&rchan->open_readers_lock); + list_for_each(p, &rchan->open_readers) { + reader = list_entry(p, struct rchan_reader, list); + if (!reader->vfs_reader) + reader->rchan = NULL; + } + read_unlock(&rchan->open_readers_lock); +} + +/** + * rchan_alloc_id - reserve a channel id and store associated channel + * @rchan: the channel + * + * Returns channel id if successful, -1 otherwise. + */ +static inline int +rchan_alloc_id(struct rchan *rchan) +{ + int i; + int rchan_id = -1; + + if (rchan == NULL) + return -1; + + write_lock(&rchan_table_lock); + for (i = 0; i < RELAY_MAX_CHANNELS; i++) { + if (rchan_table[i] == NULL) { + rchan_table[i] = rchan; + rchan_id = rchan->id = i; + break; + } + } + if (rchan_id != -1) + atomic_inc(&rchan->refcount); + write_unlock(&rchan_table_lock); + + return rchan_id; +} + +/** + * rchan_free_id - revoke a channel id and remove associated channel + * @rchan_id: the channel id + */ +static inline void +rchan_free_id(int rchan_id) +{ + struct rchan *rchan; + + if ((rchan_id < 0) || (rchan_id >= RELAY_MAX_CHANNELS)) + return; + + write_lock(&rchan_table_lock); + rchan = rchan_table[rchan_id]; + rchan_table[rchan_id] = NULL; + write_unlock(&rchan_table_lock); +} + +/** + * rchan_destroy_buf - destroy the current channel buffer + * @rchan: the channel + */ +static inline int +rchan_destroy_buf(struct rchan *rchan) +{ + int err = 0; + + if (rchan->buf && !rchan->init_buf) + err = free_rchan_buf(rchan->buf, + rchan->buf_page_array, + rchan->buf_page_count); + + return err; +} + +/** + * remove_rchan_file - remove the channel file + * @private: pointer to the channel struct + * + * Internal - manages the removal of old channel file + */ +static void +remove_rchan_file(void *private) +{ + struct rchan *rchan = (struct rchan *)private; + + relayfs_remove_file(rchan->dentry); +} + + +/** + * relay_release - perform end-of-buffer processing for last buffer + * @rchan: the channel + * + * Returns 0 if successful, negative otherwise. + * + * Releases the channel buffer, destroys the channel, and removes the + * relay file from the relayfs filesystem. Should only be called from + * rchan_put(). If we're here, it means by definition refcount is 0. + */ +static int +relay_release(struct rchan *rchan) +{ + int err = 0; + + if (rchan == NULL) { + err = -EBADF; + goto exit; + } + + err = rchan_destroy_buf(rchan); + if (err) + goto exit; + + rchan_free_id(rchan->id); + + INIT_WORK(&rchan->work, remove_rchan_file, rchan); + schedule_delayed_work(&rchan->work, 1); + + clear_readers(rchan); + kfree(rchan); +exit: + return err; +} + +/** + * rchan_get - decrement channel refcount, releasing it if 0 + * @rchan: the channel + * + * If the refcount reaches 0, the channel will be destroyed. + */ +void +rchan_put(struct rchan *rchan) +{ + if (atomic_dec_and_test(&rchan->refcount)) + relay_release(rchan); +} + +/** + * relay_reserve - reserve a slot in the channel buffer + * @rchan: the channel + * @len: the length of the slot to reserve + * @td: the time delta between buffer start and current write, or TSC + * @err: receives the result flags + * @interrupting: 1 if interrupting previous, used only in locking scheme + * + * Returns pointer to the beginning of the reserved slot, NULL if error. + * + * The errcode value contains the result flags and is an ORed combination + * of the following: + * + * RELAY_BUFFER_SWITCH_NONE - no buffer switch occurred + * RELAY_EVENT_DISCARD_NONE - event should not be discarded + * RELAY_BUFFER_SWITCH - buffer switch occurred + * RELAY_EVENT_DISCARD - event should be discarded (all buffers are full) + * RELAY_EVENT_TOO_LONG - event won't fit into even an empty buffer + * + * buffer_start and buffer_end callbacks are triggered at this point + * if applicable. + */ +char * +relay_reserve(struct rchan *rchan, + u32 len, + struct timeval *ts, + u32 *td, + int *err, + int *interrupting) +{ + if (rchan == NULL) + return NULL; + + *interrupting = 0; + + return rchan->relay_ops->reserve(rchan, len, ts, td, err, interrupting); +} + + +/** + * wakeup_readers - wake up VFS readers waiting on a channel + * @private: the channel + * + * This is the work function used to defer reader waking. The + * reason waking is deferred is that calling directly from commit + * causes problems if you're writing from say the scheduler. + */ +static void +wakeup_readers(void *private) +{ + struct rchan *rchan = (struct rchan *)private; + + wake_up_interruptible(&rchan->read_wait); +} + + +/** + * relay_commit - commit a reserved slot in the buffer + * @rchan: the channel + * @from: commit the length starting here + * @len: length committed + * @interrupting: 1 if interrupting previous, used only in locking scheme + * + * After the write into the reserved buffer has been complted, this + * function must be called in order for the relay to determine whether + * buffers are complete and to wake up VFS readers. + * + * delivery callback is triggered at this point if applicable. + */ +void +relay_commit(struct rchan *rchan, + char *from, + u32 len, + int reserve_code, + int interrupting) +{ + int deliver; + + if (rchan == NULL) + return; + + deliver = packet_delivery(rchan) || + (reserve_code & RELAY_BUFFER_SWITCH); + + rchan->relay_ops->commit(rchan, from, len, deliver, interrupting); + + /* The params are always the same, so no worry about re-queuing */ + if (deliver && waitqueue_active(&rchan->read_wait)) { + PREPARE_WORK(&rchan->wake_readers, wakeup_readers, rchan); + schedule_delayed_work(&rchan->wake_readers, 1); + } +} + +/** + * relay_get_offset - get current and max channel buffer offsets + * @rchan: the channel + * @max_offset: maximum channel offset + * + * Returns the current and maximum channel buffer offsets. + */ +u32 +relay_get_offset(struct rchan *rchan, u32 *max_offset) +{ + return rchan->relay_ops->get_offset(rchan, max_offset); +} + +/** + * reset_index - try once to reset the current channel index + * @rchan: the channel + * @old_index: the index read before reset + * + * Attempts to reset the channel index to 0. It tries once, and + * if it fails, returns negative, 0 otherwise. + */ +int +reset_index(struct rchan *rchan, u32 old_index) +{ + return rchan->relay_ops->reset_index(rchan, old_index); +} + +/* + * close() vm_op implementation for relayfs file mapping. + */ +static void +relay_file_mmap_close(struct vm_area_struct *vma) +{ + struct file *filp = vma->vm_file; + struct rchan_reader *reader; + struct rchan *rchan; + + reader = (struct rchan_reader *)filp->private_data; + rchan = reader->rchan; + + atomic_dec(&rchan->mapped); + + rchan->callbacks->fileop_notify(reader->rchan->id, filp, + RELAY_FILE_UNMAP); +} + +/* + * vm_ops for relay file mappings. + */ +static struct vm_operations_struct relay_file_mmap_ops = { + .close = relay_file_mmap_close +}; + +/* \begin{Code inspired from BTTV driver} */ +static inline unsigned long +kvirt_to_pa(unsigned long adr) +{ + unsigned long kva, ret; + + kva = (unsigned long) page_address(vmalloc_to_page((void *) adr)); + kva |= adr & (PAGE_SIZE - 1); + ret = __pa(kva); + return ret; +} + +static int +relay_mmap_region(struct vm_area_struct *vma, + const char *adr, + const char *start_pos, + unsigned long size) +{ + unsigned long start = (unsigned long) adr; + unsigned long page, pos; + + pos = (unsigned long) start_pos; + + while (size > 0) { + page = kvirt_to_pa(pos); + if (remap_page_range(vma, start, page, PAGE_SIZE, PAGE_SHARED)) + return -EAGAIN; + start += PAGE_SIZE; + pos += PAGE_SIZE; + size -= PAGE_SIZE; + } + + return 0; +} +/* \end{Code inspired from BTTV driver} */ + +/** + * relay_mmap_buffer: - mmap buffer to process address space + * @rchan_id: relay channel id + * @vma: vm_area_struct describing memory to be mapped + * + * Returns: + * 0 if ok + * -EAGAIN, when remap failed + * -EINVAL, invalid requested length + * + * Caller should already have grabbed mmap_sem. + */ +int +__relay_mmap_buffer(struct rchan *rchan, + struct vm_area_struct *vma) +{ + int err = 0; + unsigned long length = vma->vm_end - vma->vm_start; + struct file *filp = vma->vm_file; + + if (rchan == NULL) { + err = -EBADF; + goto exit; + } + + if (rchan->init_buf) { + err = -EPERM; + goto exit; + } + + if (length != (unsigned long)rchan->alloc_size) { + err = -EINVAL; + goto exit; + } + + err = relay_mmap_region(vma, + (char *)vma->vm_start, + rchan->buf, + rchan->alloc_size); + + if (err == 0) { + vma->vm_ops = &relay_file_mmap_ops; + err = rchan->callbacks->fileop_notify(rchan->id, filp, + RELAY_FILE_MAP); + if (err == 0) + atomic_inc(&rchan->mapped); + } +exit: + return err; +} + +/* + * High-level relayfs kernel API. See Documentation/filesystems/relafys.txt. + */ + +/* + * rchan_callback implementations defining default channel behavior. Used + * in place of corresponding NULL values in client callback struct. + */ + +/* + * buffer_end() default callback. Does nothing. + */ +static int +buffer_end_default_callback(int rchan_id, + char *current_write_pos, + char *end_of_buffer, + struct timeval end_time, + u32 end_tsc, + int using_tsc) +{ + return 0; +} + +/* + * buffer_start() default callback. Does nothing. + */ +static int +buffer_start_default_callback(int rchan_id, + char *current_write_pos, + u32 buffer_id, + struct timeval start_time, + u32 start_tsc, + int using_tsc) +{ + return 0; +} + +/* + * deliver() default callback. Does nothing. + */ +static void +deliver_default_callback(int rchan_id, char *from, u32 len) +{ +} + +/* + * user_deliver() default callback. Does nothing. + */ +static void +user_deliver_default_callback(int rchan_id, char *from, u32 len) +{ +} + +/* + * needs_resize() default callback. Does nothing. + */ +static void +needs_resize_default_callback(int rchan_id, + int resize_type, + u32 suggested_buf_size, + u32 suggested_n_bufs) +{ +} + +/* + * fileop_notify() default callback. Does nothing. + */ +static int +fileop_notify_default_callback(int rchan_id, + struct file *filp, + enum relay_fileop fileop) +{ + return 0; +} + +/* + * ioctl() default callback. Does nothing. + */ +static int +ioctl_default_callback(int rchan_id, + unsigned int cmd, + unsigned long arg) +{ + return 0; +} + +/* relay channel default callbacks */ +static struct rchan_callbacks default_channel_callbacks = { + .buffer_start = buffer_start_default_callback, + .buffer_end = buffer_end_default_callback, + .deliver = deliver_default_callback, + .user_deliver = user_deliver_default_callback, + .needs_resize = needs_resize_default_callback, + .fileop_notify = fileop_notify_default_callback, + .ioctl = ioctl_default_callback, +}; + +/** + * check_attribute_flags - check sanity of channel attributes + * @flags: channel attributes + * @resizeable: 1 if true + * + * Returns 0 if successful, negative otherwise. + */ +static int +check_attribute_flags(u32 *attribute_flags, int resizeable) +{ + u32 flags = *attribute_flags; + + if (!(flags & RELAY_DELIVERY_BULK) && !(flags & RELAY_DELIVERY_PACKET)) + return -EINVAL; /* Delivery mode must be specified */ + + if (!(flags & RELAY_USAGE_SMP) && !(flags & RELAY_USAGE_GLOBAL)) + return -EINVAL; /* Usage must be specified */ + + if (resizeable) { /* Resizeable can never be continuous */ + *attribute_flags &= ~RELAY_MODE_CONTINUOUS; + *attribute_flags |= RELAY_MODE_NO_OVERWRITE; + } + + if ((flags & RELAY_MODE_CONTINUOUS) && + (flags & RELAY_MODE_NO_OVERWRITE)) + return -EINVAL; /* Can't have it both ways */ + + if (!(flags & RELAY_MODE_CONTINUOUS) && + !(flags & RELAY_MODE_NO_OVERWRITE)) + *attribute_flags |= RELAY_MODE_CONTINUOUS; /* Default to continuous */ + + if (!(flags & RELAY_SCHEME_ANY)) + return -EINVAL; /* One or both must be specified */ + else if (flags & RELAY_SCHEME_LOCKLESS) { + if (have_cmpxchg()) + *attribute_flags &= ~RELAY_SCHEME_LOCKING; + else if (flags & RELAY_SCHEME_LOCKING) + *attribute_flags &= ~RELAY_SCHEME_LOCKLESS; + else + return -EINVAL; /* Locking scheme not an alternative */ + } + + if (!(flags & RELAY_TIMESTAMP_ANY)) + return -EINVAL; /* One or both must be specified */ + else if (flags & RELAY_TIMESTAMP_TSC) { + if (have_tsc()) + *attribute_flags &= ~RELAY_TIMESTAMP_GETTIMEOFDAY; + else if (flags & RELAY_TIMESTAMP_GETTIMEOFDAY) + *attribute_flags &= ~RELAY_TIMESTAMP_TSC; + else + return -EINVAL; /* gettimeofday not an alternative */ + } + + return 0; +} + +/* + * High-level API functions. + */ + +/** + * __relay_reset - internal reset function + * @rchan: the channel + * @init: 1 if this is a first-time channel initialization + * + * See relay_reset for description of effect. + */ +void +__relay_reset(struct rchan *rchan, int init) +{ + int i; + + if (init) { + rchan->version = RELAYFS_CHANNEL_VERSION; + init_MUTEX(&rchan->resize_sem); + init_waitqueue_head(&rchan->read_wait); + init_waitqueue_head(&rchan->write_wait); + atomic_set(&rchan->refcount, 0); + INIT_LIST_HEAD(&rchan->open_readers); + rchan->open_readers_lock = RW_LOCK_UNLOCKED; + } + + rchan->buf_id = rchan->buf_idx = 0; + atomic_set(&rchan->suspended, 0); + atomic_set(&rchan->mapped, 0); + rchan->half_switch = 0; + rchan->bufs_produced = 0; + rchan->bufs_consumed = 0; + rchan->bytes_consumed = 0; + rchan->read_start = 0; + rchan->initialized = 0; + rchan->finalized = 0; + rchan->resize_min = rchan->resize_max = 0; + rchan->resizing = 0; + rchan->replace_buffer = 0; + rchan->resize_buf = NULL; + rchan->resize_buf_size = 0; + rchan->resize_alloc_size = 0; + rchan->resize_n_bufs = 0; + rchan->resize_err = 0; + rchan->resize_failures = 0; + rchan->resize_order = 0; + + rchan->expand_page_array = NULL; + rchan->expand_page_count = 0; + rchan->shrink_page_array = NULL; + rchan->shrink_page_count = 0; + rchan->resize_page_array = NULL; + rchan->resize_page_count = 0; + rchan->old_buf_page_array = NULL; + rchan->expand_buf_id = 0; + + INIT_WORK(&rchan->wake_readers, NULL, NULL); + INIT_WORK(&rchan->wake_writers, NULL, NULL); + + for (i = 0; i < RELAY_MAX_BUFS; i++) + rchan->unused_bytes[i] = 0; + + rchan->relay_ops->reset(rchan, init); +} + +/** + * relay_reset - reset the channel + * @rchan: the channel + * + * Returns 0 if successful, negative if not. + * + * This has the effect of erasing all data from the buffer and + * restarting the channel in its initial state. The buffer itself + * is not freed, so any mappings are still in effect. + * + * NOTE: Care should be taken that the channel isn't actually + * being used by anything when this call is made. + */ +int +relay_reset(int rchan_id) +{ + struct rchan *rchan; + + rchan = rchan_get(rchan_id); + if (rchan == NULL) + return -EBADF; + + __relay_reset(rchan, 0); + update_readers_consumed(rchan, 0, 0); + + rchan_put(rchan); + + return 0; +} + +/** + * check_init_buf - check the sanity of init_buf, if present + * @init_buf: the initbuf + * @init_buf_size: the total initbuf size + * @bufsize: the channel's sub-buffer size + * @nbufs: the number of sub-buffers in the channel + * + * Returns 0 if ok, negative otherwise. + */ +static int +check_init_buf(char *init_buf, u32 init_buf_size, u32 bufsize, u32 nbufs) +{ + int err = 0; + + if (init_buf && nbufs == 1) /* 1 sub-buffer makes no sense */ + err = -EINVAL; + + if (init_buf && (bufsize * nbufs != init_buf_size)) + err = -EINVAL; + + return err; +} + +/** + * rchan_create_buf - allocate the initial channel buffer + * @rchan: the channel + * @size_alloc: the total size of the channel buffer + * + * Returns 0 if successful, negative otherwise. + */ +static inline int +rchan_create_buf(struct rchan *rchan, int size_alloc) +{ + struct page **page_array; + int page_count; + + if ((rchan->buf = (char *)alloc_rchan_buf(size_alloc, &page_array, &page_count)) == NULL) { + rchan->buf_page_array = NULL; + rchan->buf_page_count = 0; + return -ENOMEM; + } + + rchan->buf_page_array = page_array; + rchan->buf_page_count = page_count; + + return 0; +} + +/** + * rchan_create - allocate and initialize a channel, including buffer + * @chanpath: path specifying the relayfs channel file to create + * @bufsize: the size of the sub-buffers within the channel buffer + * @nbufs: the number of sub-buffers within the channel buffer + * @rchan_flags: flags specifying buffer attributes + * @err: err code + * + * Returns channel if successful, NULL otherwise, err receives errcode. + * + * Allocates a struct rchan representing a relay channel, according + * to the attributes passed in via rchan_flags. Does some basic sanity + * checking but doesn't try to do anything smart. In particular, the + * number of buffers must be a power of 2, and if the lockless scheme + * is being used, the sub-buffer size must also be a power of 2. The + * locking scheme can use buffers of any size. + */ +static struct rchan * +rchan_create(const char *chanpath, + int bufsize, + int nbufs, + u32 rchan_flags, + char *init_buf, + u32 init_buf_size, + int *err) +{ + int size_alloc; + struct rchan *rchan = NULL; + + *err = 0; + + rchan = (struct rchan *)kmalloc(sizeof(struct rchan), GFP_KERNEL); + if (rchan == NULL) { + *err = -ENOMEM; + return NULL; + } + rchan->buf = rchan->init_buf = NULL; + + *err = check_init_buf(init_buf, init_buf_size, bufsize, nbufs); + if (*err) + goto exit; + + if (nbufs == 1 && bufsize) { + rchan->n_bufs = nbufs; + rchan->buf_size = bufsize; + size_alloc = bufsize; + goto alloc; + } + + if (bufsize <= 0 || + (rchan_flags & RELAY_SCHEME_LOCKLESS && hweight32(bufsize) != 1) || + hweight32(nbufs) != 1 || + nbufs < RELAY_MIN_BUFS || + nbufs > RELAY_MAX_BUFS) { + *err = -EINVAL; + goto exit; + } + + size_alloc = FIX_SIZE(bufsize * nbufs); + if (size_alloc > RELAY_MAX_BUF_SIZE) { + *err = -EINVAL; + goto exit; + } + rchan->n_bufs = nbufs; + rchan->buf_size = bufsize; + + if (rchan_flags & RELAY_SCHEME_LOCKLESS) { + offset_bits(rchan) = ffs(bufsize) - 1; + offset_mask(rchan) = RELAY_BUF_OFFSET_MASK(offset_bits(rchan)); + bufno_bits(rchan) = ffs(nbufs) - 1; + } +alloc: + if (rchan_alloc_id(rchan) == -1) { + *err = -ENOMEM; + goto exit; + } + + if (init_buf == NULL) { + *err = rchan_create_buf(rchan, size_alloc); + if (*err) { + rchan_free_id(rchan->id); + goto exit; + } + } else + rchan->buf = rchan->init_buf = init_buf; + + rchan->alloc_size = size_alloc; + + if (rchan_flags & RELAY_SCHEME_LOCKLESS) + rchan->relay_ops = &lockless_ops; + else + rchan->relay_ops = &locking_ops; + +exit: + if (*err) { + kfree(rchan); + rchan = NULL; + } + + return rchan; +} + + +static char tmpname[NAME_MAX]; + +/** + * rchan_create_dir - create directory for file + * @chanpath: path to file, including filename + * @residual: filename remaining after parse + * @topdir: the directory filename should be created in + * + * Returns 0 if successful, negative otherwise. + * + * Inspired by xlate_proc_name() in procfs. Given a file path which + * includes the filename, creates any and all directories necessary + * to create the file. + */ +static int +rchan_create_dir(const char * chanpath, + const char **residual, + struct dentry **topdir) +{ + const char *cp = chanpath, *next; + struct dentry *parent = NULL; + int len, err = 0; + + while (1) { + next = strchr(cp, '/'); + if (!next) + break; + + len = next - cp; + + strncpy(tmpname, cp, len); + tmpname[len] = '\0'; + err = relayfs_create_dir(tmpname, parent, &parent); + if (err && (err != -EEXIST)) + return err; + cp += len + 1; + } + + *residual = cp; + *topdir = parent; + + return err; +} + +/** + * rchan_create_file - create file, including parent directories + * @chanpath: path to file, including filename + * @dentry: result dentry + * @data: data to associate with the file + * + * Returns 0 if successful, negative otherwise. + */ +static int +rchan_create_file(const char * chanpath, + struct dentry **dentry, + struct rchan * data, + int mode) +{ + int err; + const char * fname; + struct dentry *topdir; + + err = rchan_create_dir(chanpath, &fname, &topdir); + if (err && (err != -EEXIST)) + return err; + + err = relayfs_create_file(fname, topdir, dentry, (void *)data, mode); + + return err; +} + +/** + * relay_open - create a new file/channel buffer in relayfs + * @chanpath: name of file to create, including path + * @bufsize: size of sub-buffers + * @nbufs: number of sub-buffers + * @flags: channel attributes + * @callbacks: client callback functions + * @start_reserve: number of bytes to reserve at start of each sub-buffer + * @end_reserve: number of bytes to reserve at end of each sub-buffer + * @rchan_start_reserve: additional reserve at start of first sub-buffer + * @resize_min: minimum total buffer size, if set + * @resize_max: maximum total buffer size, if set + * @mode: the perms to be given to the relayfs file, 0 to accept defaults + * @init_buf: initial memory buffer to start out with, NULL if N/A + * @init_buf_size: initial memory buffer size to start out with, 0 if N/A + * + * Returns channel id if successful, negative otherwise. + * + * Creates a relay channel using the sizes and attributes specified. + * The default permissions, used if mode == 0 are S_IRUSR | S_IWUSR. See + * Documentation/filesystems/relayfs.txt for details. + */ +int +relay_open(const char *chanpath, + int bufsize, + int nbufs, + u32 flags, + struct rchan_callbacks *channel_callbacks, + u32 start_reserve, + u32 end_reserve, + u32 rchan_start_reserve, + u32 resize_min, + u32 resize_max, + int mode, + char *init_buf, + u32 init_buf_size) +{ + int err; + struct rchan *rchan; + struct dentry *dentry; + struct rchan_callbacks *callbacks = NULL; + + if (chanpath == NULL) + return -EINVAL; + + if (nbufs != 1) { + err = check_attribute_flags(&flags, resize_min ? 1 : 0); + if (err) + return err; + } + + rchan = rchan_create(chanpath, bufsize, nbufs, flags, init_buf, init_buf_size, &err); + + if (err < 0) + return err; + + /* Create file in fs */ + if ((err = rchan_create_file(chanpath, &dentry, rchan, mode)) < 0) { + rchan_destroy_buf(rchan); + rchan_free_id(rchan->id); + kfree(rchan); + return err; + } + + rchan->dentry = dentry; + + if (channel_callbacks == NULL) + callbacks = &default_channel_callbacks; + else + callbacks = channel_callbacks; + + if (callbacks->buffer_end == NULL) + callbacks->buffer_end = buffer_end_default_callback; + if (callbacks->buffer_start == NULL) + callbacks->buffer_start = buffer_start_default_callback; + if (callbacks->deliver == NULL) + callbacks->deliver = deliver_default_callback; + if (callbacks->user_deliver == NULL) + callbacks->user_deliver = user_deliver_default_callback; + if (callbacks->needs_resize == NULL) + callbacks->needs_resize = needs_resize_default_callback; + if (callbacks->fileop_notify == NULL) + callbacks->fileop_notify = fileop_notify_default_callback; + if (callbacks->ioctl == NULL) + callbacks->ioctl = ioctl_default_callback; + rchan->callbacks = callbacks; + + /* Just to let the client know the sizes used */ + rchan->callbacks->needs_resize(rchan->id, + RELAY_RESIZE_REPLACED, + rchan->buf_size, + rchan->n_bufs); + + rchan->flags = flags; + rchan->start_reserve = start_reserve; + rchan->end_reserve = end_reserve; + rchan->rchan_start_reserve = rchan_start_reserve; + + __relay_reset(rchan, 1); + + if (resize_min > 0 && resize_max > 0 && + resize_max < RELAY_MAX_TOTAL_BUF_SIZE) { + rchan->resize_min = resize_min; + rchan->resize_max = resize_max; + init_shrink_timer(rchan); + } + + rchan_get(rchan->id); + + return rchan->id; +} + +/** + * relay_discard_init_buf - alloc channel buffer and copy init_buf into it + * @rchan_id: the channel id + * + * Returns 0 if successful, negative otherwise. + * + * NOTE: May sleep. Should also be called only when the channel isn't + * actively being written into. + */ +int +relay_discard_init_buf(int rchan_id) +{ + struct rchan *rchan; + int err = 0; + + rchan = rchan_get(rchan_id); + if (rchan == NULL) + return -EBADF; + + if (rchan->init_buf == NULL) { + err = -EINVAL; + goto out; + } + + err = rchan_create_buf(rchan, rchan->alloc_size); + if (err) + goto out; + + memcpy(rchan->buf, rchan->init_buf, rchan->n_bufs * rchan->buf_size); + rchan->init_buf = NULL; +out: + rchan_put(rchan); + + return err; +} + +/** + * relay_finalize - perform end-of-buffer processing for last buffer + * @rchan_id: the channel id + * @releasing: true if called when releasing file + * + * Returns 0 if successful, negative otherwise. + */ +static int +relay_finalize(int rchan_id) +{ + struct rchan *rchan = rchan_get(rchan_id); + if (rchan == NULL) + return -EBADF; + + if (rchan->finalized == 0) { + rchan->relay_ops->finalize(rchan); + rchan->finalized = 1; + } + + if (waitqueue_active(&rchan->read_wait)) { + PREPARE_WORK(&rchan->wake_readers, wakeup_readers, rchan); + schedule_delayed_work(&rchan->wake_readers, 1); + } + + rchan_put(rchan); + + return 0; +} + +/** + * restore_callbacks - restore default channel callbacks + * @rchan: the channel + * + * Restore callbacks to the default versions. + */ +static inline void +restore_callbacks(struct rchan *rchan) +{ + if (rchan->callbacks != &default_channel_callbacks) + rchan->callbacks = &default_channel_callbacks; +} + +/** + * relay_close - close the channel + * @rchan_id: relay channel id + * + * Finalizes the last sub-buffer and marks the channel as finalized. + * The channel buffer and channel data structure are then freed + * automatically when the last reference to the channel is given up. + */ +int +relay_close(int rchan_id) +{ + int err; + struct rchan *rchan; + + if ((rchan_id < 0) || (rchan_id >= RELAY_MAX_CHANNELS)) + return -EBADF; + + err = relay_finalize(rchan_id); + + if (!err) { + read_lock(&rchan_table_lock); + rchan = rchan_table[rchan_id]; + read_unlock(&rchan_table_lock); + + if (rchan) { + restore_callbacks(rchan); + if (rchan->resize_min) + del_timer(&rchan->shrink_timer); + rchan_put(rchan); + } + } + + return err; +} + +/** + * relay_write - reserve a slot in the channel and write data into it + * @rchan_id: relay channel id + * @data_ptr: data to be written into reserved slot + * @count: number of bytes to write + * @td_offset: optional offset where time delta should be written + * @wrote_pos: optional ptr returning buf pos written to, ignored if NULL + * + * Returns the number of bytes written, 0 or negative on failure. + * + * Reserves space in the channel and writes count bytes of data_ptr + * to it. Automatically performs any necessary locking, depending + * on the scheme and SMP usage in effect (no locking is done for the + * lockless scheme regardless of usage). + * + * If td_offset is >= 0, the internal time delta calculated when + * slot was reserved will be written at that offset. + * + * If wrote_pos is non-NULL, it will receive the location the data + * was written to, which may be needed for some applications but is not + * normally interesting. + */ +int +relay_write(int rchan_id, + const void *data_ptr, + size_t count, + int td_offset, + void **wrote_pos) +{ + unsigned long flags; + char *reserved, *write_pos; + int bytes_written = 0; + int reserve_code, interrupting; + struct timeval ts; + u32 td; + struct rchan *rchan; + + rchan = rchan_get(rchan_id); + if (rchan == NULL) + return -EBADF; + + relay_lock_channel(rchan, flags); /* nop for lockless */ + + write_pos = reserved = relay_reserve(rchan, count, &ts, &td, + &reserve_code, &interrupting); + + if (reserved != NULL) { + relay_write_direct(write_pos, data_ptr, count); + if ((td_offset >= 0) && (td_offset < count - sizeof(td))) + *((u32 *)(reserved + td_offset)) = td; + bytes_written = count; + } else if (reserve_code == RELAY_WRITE_TOO_LONG) + bytes_written = -EINVAL; + + if (bytes_written > 0) + relay_commit(rchan, reserved, bytes_written, reserve_code, interrupting); + + relay_unlock_channel(rchan, flags); /* nop for lockless */ + + rchan_put(rchan); + + if (wrote_pos) + *wrote_pos = reserved; + + return bytes_written; +} + +/** + * wakeup_writers - wake up VFS writers waiting on a channel + * @private: the channel + * + * This is the work function used to defer writer waking. The + * reason waking is deferred is that calling directly from + * buffers_consumed causes problems if you're writing from say + * the scheduler. + */ +static void +wakeup_writers(void *private) +{ + struct rchan *rchan = (struct rchan *)private; + + wake_up_interruptible(&rchan->write_wait); +} + + +/** + * __relay_buffers_consumed - internal version of relay_buffers_consumed + * @rchan: the relay channel + * @bufs_consumed: number of buffers to add to current count for channel + * + * Internal - updates the channel's consumed buffer count. + */ +static void +__relay_buffers_consumed(struct rchan *rchan, u32 bufs_consumed) +{ + rchan->bufs_consumed += bufs_consumed; + + if (rchan->bufs_consumed > rchan->bufs_produced) + rchan->bufs_consumed = rchan->bufs_produced; + + atomic_set(&rchan->suspended, 0); + + PREPARE_WORK(&rchan->wake_writers, wakeup_writers, rchan); + schedule_delayed_work(&rchan->wake_writers, 1); +} + +/** + * __reader_buffers_consumed - update reader/channel consumed buffer count + * @reader: channel reader + * @bufs_consumed: number of buffers to add to current count for channel + * + * Internal - updates the reader's consumed buffer count. If the reader's + * resulting total is greater than the channel's, update the channel's. +*/ +static void +__reader_buffers_consumed(struct rchan_reader *reader, u32 bufs_consumed) +{ + reader->bufs_consumed += bufs_consumed; + + if (reader->bufs_consumed > reader->rchan->bufs_consumed) + __relay_buffers_consumed(reader->rchan, bufs_consumed); +} + +/** + * relay_buffers_consumed - add to the # buffers consumed for the channel + * @reader: channel reader + * @bufs_consumed: number of buffers to add to current count for channel + * + * Adds to the channel's consumed buffer count. buffers_consumed should + * be the number of buffers newly consumed, not the total number consumed. + * + * NOTE: kernel clients don't need to call this function if the reader + * is auto-consuming or the channel is MODE_CONTINUOUS. + */ +void +relay_buffers_consumed(struct rchan_reader *reader, u32 bufs_consumed) +{ + if (reader && reader->rchan) + __reader_buffers_consumed(reader, bufs_consumed); +} + +/** + * __relay_bytes_consumed - internal version of relay_bytes_consumed + * @rchan: the relay channel + * @bytes_consumed: number of bytes to add to current count for channel + * @read_offset: where the bytes were consumed from + * + * Internal - updates the channel's consumed count. +*/ +static void +__relay_bytes_consumed(struct rchan *rchan, u32 bytes_consumed, u32 read_offset) +{ + u32 consuming_idx; + u32 unused; + + consuming_idx = read_offset / rchan->buf_size; + + if (consuming_idx >= rchan->n_bufs) + consuming_idx = rchan->n_bufs - 1; + rchan->bytes_consumed += bytes_consumed; + + unused = rchan->unused_bytes[consuming_idx]; + + if (rchan->bytes_consumed + unused >= rchan->buf_size) { + __relay_buffers_consumed(rchan, 1); + rchan->bytes_consumed = 0; + } +} + +/** + * __reader_bytes_consumed - update reader/channel consumed count + * @reader: channel reader + * @bytes_consumed: number of bytes to add to current count for channel + * @read_offset: where the bytes were consumed from + * + * Internal - updates the reader's consumed count. If the reader's + * resulting total is greater than the channel's, update the channel's. +*/ +static void +__reader_bytes_consumed(struct rchan_reader *reader, u32 bytes_consumed, u32 read_offset) +{ + u32 consuming_idx; + u32 unused; + + consuming_idx = read_offset / reader->rchan->buf_size; + + if (consuming_idx >= reader->rchan->n_bufs) + consuming_idx = reader->rchan->n_bufs - 1; + + reader->bytes_consumed += bytes_consumed; + + unused = reader->rchan->unused_bytes[consuming_idx]; + + if (reader->bytes_consumed + unused >= reader->rchan->buf_size) { + reader->bufs_consumed++; + reader->bytes_consumed = 0; + } + + if ((reader->bufs_consumed > reader->rchan->bufs_consumed) || + ((reader->bufs_consumed == reader->rchan->bufs_consumed) && + (reader->bytes_consumed > reader->rchan->bytes_consumed))) + __relay_bytes_consumed(reader->rchan, bytes_consumed, read_offset); +} + +/** + * relay_bytes_consumed - add to the # bytes consumed for the channel + * @reader: channel reader + * @bytes_consumed: number of bytes to add to current count for channel + * @read_offset: where the bytes were consumed from + * + * Adds to the channel's consumed count. bytes_consumed should be the + * number of bytes actually read e.g. return value of relay_read() and + * the read_offset should be the actual offset the bytes were read from + * e.g. the actual_read_offset set by relay_read(). See + * Documentation/filesystems/relayfs.txt for more details. + * + * NOTE: kernel clients don't need to call this function if the reader + * is auto-consuming or the channel is MODE_CONTINUOUS. + */ +void +relay_bytes_consumed(struct rchan_reader *reader, u32 bytes_consumed, u32 read_offset) +{ + if (reader && reader->rchan) + __reader_bytes_consumed(reader, bytes_consumed, read_offset); +} + +/** + * update_readers_consumed - apply offset change to reader + * @rchan: the channel + * + * Apply the consumed counts to all readers open on the channel. + */ +void +update_readers_consumed(struct rchan *rchan, u32 bufs_consumed, u32 bytes_consumed) +{ + struct list_head *p; + struct rchan_reader *reader; + + read_lock(&rchan->open_readers_lock); + list_for_each(p, &rchan->open_readers) { + reader = list_entry(p, struct rchan_reader, list); + reader->bufs_consumed = bufs_consumed; + reader->bytes_consumed = bytes_consumed; + if (reader->vfs_reader) + reader->pos.file->f_pos = 0; + else + reader->pos.f_pos = 0; + reader->offset_changed = 1; + } + read_unlock(&rchan->open_readers_lock); + rchan->read_start = 0; +} + +/** + * do_read - utility function to do the actual read to user + * @rchan: the channel + * @buf: user buf to read into, NULL if just getting info + * @count: bytes requested + * @read_offset: offset into channel + * @new_offset: new offset into channel after read + * @actual_read_offset: read offset actually used + * + * Returns the number of bytes read, 0 if none. + */ +static ssize_t +do_read(struct rchan *rchan, char *buf, size_t count, u32 read_offset, u32 *new_offset, u32 *actual_read_offset) +{ + u32 read_bufno, cur_bufno; + u32 avail_offset, cur_idx, max_offset, buf_end_offset; + u32 avail_count, buf_size; + int unused_bytes = 0; + size_t read_count = 0; + u32 last_buf_byte_offset; + + *actual_read_offset = read_offset; + + buf_size = rchan->buf_size; + if (unlikely(!buf_size)) BUG(); + + read_bufno = read_offset / buf_size; + if (unlikely(read_bufno >= RELAY_MAX_BUFS)) BUG(); + unused_bytes = rchan->unused_bytes[read_bufno]; + + avail_offset = cur_idx = relay_get_offset(rchan, &max_offset); + + if (cur_idx == read_offset) { + if (atomic_read(&rchan->suspended) == 1) { + read_offset += 1; + if (read_offset >= max_offset) + read_offset = 0; + *actual_read_offset = read_offset; + } else { + *new_offset = read_offset; + return 0; + } + } else { + last_buf_byte_offset = (read_bufno + 1) * buf_size - 1; + if (read_offset == last_buf_byte_offset) { + if (unused_bytes != 1) { + read_offset += 1; + if (read_offset >= max_offset) + read_offset = 0; + *actual_read_offset = read_offset; + } + } + } + + read_bufno = read_offset / buf_size; + if (unlikely(read_bufno >= RELAY_MAX_BUFS)) BUG(); + unused_bytes = rchan->unused_bytes[read_bufno]; + + cur_bufno = cur_idx / buf_size; + + buf_end_offset = (read_bufno + 1) * buf_size - unused_bytes; + if (avail_offset > buf_end_offset) + avail_offset = buf_end_offset; + else if (avail_offset < read_offset) + avail_offset = buf_end_offset; + avail_count = avail_offset - read_offset; + read_count = avail_count >= count ? count : avail_count; + + if (read_count && buf != NULL) + if (copy_to_user(buf, rchan->buf + read_offset, read_count)) + return -EFAULT; + + if (read_bufno == cur_bufno) + if (read_count && (read_offset + read_count >= buf_end_offset) && (read_offset + read_count <= cur_idx)) { + *new_offset = cur_idx; + return read_count; + } + + if (read_offset + read_count + unused_bytes > max_offset) + *new_offset = 0; + else if (read_offset + read_count >= buf_end_offset) + *new_offset = read_offset + read_count + unused_bytes; + else + *new_offset = read_offset + read_count; + + return read_count; +} + +/** + * __relay_read - read bytes from channel, relative to current reader pos + * @reader: channel reader + * @buf: user buf to read into, NULL if just getting info + * @count: bytes requested + * @read_offset: offset into channel + * @new_offset: new offset into channel after read + * @actual_read_offset: read offset actually used + * @wait: if non-zero, wait for something to read + * + * Internal - see relay_read() for details. + * + * Returns the number of bytes read, 0 if none, negative on failure. + */ +static ssize_t +__relay_read(struct rchan_reader *reader, char *buf, size_t count, u32 read_offset, u32 *new_offset, u32 *actual_read_offset, int wait) +{ + int err = 0; + size_t read_count = 0; + struct rchan *rchan = reader->rchan; + + if (!wait && !rchan->initialized) + return -EAGAIN; + + if (using_lockless(rchan)) + read_offset &= idx_mask(rchan); + + if (read_offset >= rchan->n_bufs * rchan->buf_size) { + *new_offset = 0; + if (!wait) + return -EAGAIN; + else + return -EINTR; + } + + if (buf != NULL && wait) { + err = wait_event_interruptible(rchan->read_wait, + ((rchan->finalized == 1) || + (atomic_read(&rchan->suspended) == 1) || + (relay_get_offset(rchan, NULL) != read_offset))); + + if (rchan->finalized) + return 0; + + if (reader->offset_changed) { + reader->offset_changed = 0; + return -EINTR; + } + + if (err) + return err; + } + + read_count = do_read(rchan, buf, count, read_offset, new_offset, actual_read_offset); + + if (read_count < 0) + err = read_count; + + if (err) + return err; + else + return read_count; +} + +/** + * relay_read - read bytes from channel, relative to current reader pos + * @reader: channel reader + * @buf: user buf to read into, NULL if just getting info + * @count: bytes requested + * @wait: if non-zero, wait for something to read + * @actual_read_offset: set read offset actually used, must not be NULL + * + * Reads count bytes from the channel, or as much as is available within + * the sub-buffer currently being read. The read offset that will be + * read from is the position contained within the reader object. If the + * wait flag is set, buf is non-NULL, and there is nothing available, + * it will wait until there is. If the wait flag is 0 and there is + * nothing available, -EAGAIN is returned. If buf is NULL, the value + * returned is the number of bytes that would have been read. + * actual_read_offset is the value that should be passed as the read + * offset to relay_bytes_consumed, needed only if the reader is not + * auto-consuming and the channel is MODE_NO_OVERWRITE, but in any case, + * it must not be NULL. See Documentation/filesystems/relayfs.txt for + * more details. + */ +ssize_t +relay_read(struct rchan_reader *reader, char *buf, size_t count, int wait, u32 *actual_read_offset) +{ + u32 new_offset; + u32 read_offset; + ssize_t read_count; + + if (reader == NULL || reader->rchan == NULL) + return -EBADF; + + if (actual_read_offset == NULL) + return -EINVAL; + + if (reader->vfs_reader) + read_offset = (u32)(reader->pos.file->f_pos); + else + read_offset = reader->pos.f_pos; + *actual_read_offset = read_offset; + + read_count = __relay_read(reader, buf, count, read_offset, + &new_offset, actual_read_offset, wait); + + if (read_count < 0) + return read_count; + + if (reader->vfs_reader) { + reader->pos.file->f_pos = new_offset; + down(&reader->rchan->resize_sem); + reader->rchan->read_start = new_offset; + up(&reader->rchan->resize_sem); + } else + reader->pos.f_pos = new_offset; + + if (reader->auto_consume && ((read_count) || (new_offset != read_offset))) + __reader_bytes_consumed(reader, read_count, *actual_read_offset); + + if (read_count == 0 && !wait) + return -EAGAIN; + + return read_count; +} + +/** + * relay_bytes_avail - number of bytes available in current sub-buffer + * @reader: channel reader + * + * Returns the number of bytes available relative to the reader's + * current read position within the corresponding sub-buffer, 0 if + * there is nothing available. See Documentation/filesystems/relayfs.txt + * for more details. + */ +ssize_t +relay_bytes_avail(struct rchan_reader *reader) +{ + u32 f_pos; + u32 new_offset; + u32 actual_read_offset; + ssize_t bytes_read; + + if (reader == NULL || reader->rchan == NULL) + return -EBADF; + + if (reader->vfs_reader) + f_pos = (u32)reader->pos.file->f_pos; + else + f_pos = reader->pos.f_pos; + new_offset = f_pos; + + bytes_read = __relay_read(reader, NULL, reader->rchan->buf_size, + f_pos, &new_offset, &actual_read_offset, 0); + + if ((new_offset != f_pos) && + ((bytes_read == -EINTR) || (bytes_read == 0))) + bytes_read = -EAGAIN; + else if ((bytes_read < 0) && (bytes_read != -EAGAIN)) + bytes_read = 0; + + return bytes_read; +} + +/** + * rchan_empty - boolean, is the channel empty wrt reader? + * @reader: channel reader + * + * Returns 1 if the channel is empty, 0 otherwise. + */ +int +rchan_empty(struct rchan_reader *reader) +{ + ssize_t avail_count; + u32 buffers_ready; + struct rchan *rchan = reader->rchan; + u32 cur_idx, curbuf_bytes; + int mapped; + + if (atomic_read(&rchan->suspended) == 1) + return 0; + + mapped = atomic_read(&rchan->mapped); + + if (mapped && bulk_delivery(rchan)) { + buffers_ready = rchan->bufs_produced - rchan->bufs_consumed; + return buffers_ready ? 0 : 1; + } + + if (mapped && packet_delivery(rchan)) { + buffers_ready = rchan->bufs_produced - rchan->bufs_consumed; + if (buffers_ready) + return 0; + else { + cur_idx = relay_get_offset(rchan, NULL); + curbuf_bytes = cur_idx % rchan->buf_size; + return curbuf_bytes == rchan->bytes_consumed ? 1 : 0; + } + } + + avail_count = relay_bytes_avail(reader); + + return avail_count ? 0 : 1; +} + +/** + * rchan_full - boolean, is the channel full wrt consuming reader? + * @reader: channel reader + * + * Returns 1 if the channel is full, 0 otherwise. + */ +int +rchan_full(struct rchan_reader *reader) +{ + u32 buffers_ready; + struct rchan *rchan = reader->rchan; + + if (mode_continuous(rchan)) + return 0; + + buffers_ready = rchan->bufs_produced - rchan->bufs_consumed; + + return buffers_ready > reader->rchan->n_bufs - 1 ? 1 : 0; +} + +/** + * relay_info - get status and other information about a relay channel + * @rchan_id: relay channel id + * @rchan_info: pointer to the rchan_info struct to be filled in + * + * Fills in an rchan_info struct with channel status and attribute + * information. See Documentation/filesystems/relayfs.txt for details. + * + * Returns 0 if successful, negative otherwise. + */ +int +relay_info(int rchan_id, struct rchan_info *rchan_info) +{ + int i; + struct rchan *rchan; + + rchan = rchan_get(rchan_id); + if (rchan == NULL) + return -EBADF; + + rchan_info->flags = rchan->flags; + rchan_info->buf_size = rchan->buf_size; + rchan_info->buf_addr = rchan->buf; + rchan_info->alloc_size = rchan->alloc_size; + rchan_info->n_bufs = rchan->n_bufs; + rchan_info->cur_idx = relay_get_offset(rchan, NULL); + rchan_info->bufs_produced = rchan->bufs_produced; + rchan_info->bufs_consumed = rchan->bufs_consumed; + rchan_info->buf_id = rchan->buf_id; + + for (i = 0; i < rchan->n_bufs; i++) { + rchan_info->unused_bytes[i] = rchan->unused_bytes[i]; + if (using_lockless(rchan)) + rchan_info->buffer_complete[i] = (atomic_read(&fill_count(rchan, i)) == rchan->buf_size); + else + rchan_info->buffer_complete[i] = 0; + } + + rchan_put(rchan); + + return 0; +} + +/** + * __add_rchan_reader - creates and adds a reader to a channel + * @rchan: relay channel + * @filp: the file associated with rchan, if applicable + * @auto_consume: boolean, whether reader's reads automatically consume + * @map_reader: boolean, whether reader's reading via a channel mapping + * + * Returns a pointer to the reader object create, NULL if unsuccessful + * + * Creates and initializes an rchan_reader object for reading the channel. + * If filp is non-NULL, the reader is a VFS reader, otherwise not. + * + * If the reader is a map reader, it isn't considered a VFS reader for + * our purposes. Also, map_readers can't be auto-consuming. + */ +struct rchan_reader * +__add_rchan_reader(struct rchan *rchan, struct file *filp, int auto_consume, int map_reader) +{ + struct rchan_reader *reader; + u32 will_read; + + reader = kmalloc(sizeof(struct rchan_reader), GFP_KERNEL); + + if (reader) { + reader->rchan = rchan; + if (filp) { + reader->vfs_reader = 1; + down(&rchan->resize_sem); + filp->f_pos = rchan->read_start; + up(&rchan->resize_sem); + reader->pos.file = filp; + } else { + reader->vfs_reader = 0; + reader->pos.f_pos = 0; + } + reader->map_reader = map_reader; + reader->auto_consume = auto_consume; + + if (!map_reader) { + will_read = rchan->bufs_produced % rchan->n_bufs; + if (!will_read && atomic_read(&rchan->suspended)) + will_read = rchan->n_bufs; + reader->bufs_consumed = rchan->bufs_produced - will_read; + rchan->bufs_consumed = reader->bufs_consumed; + rchan->bytes_consumed = reader->bytes_consumed = 0; + reader->offset_changed = 0; + } + + write_lock(&rchan->open_readers_lock); + list_add(&reader->list, &rchan->open_readers); + write_unlock(&rchan->open_readers_lock); + } + + return reader; +} + +/** + * add_rchan_reader - create a reader for a channel + * @rchan_id: relay channel handle + * @auto_consume: boolean, whether reader's reads automatically consume + * + * Returns a pointer to the reader object created, NULL if unsuccessful + * + * Creates and initializes an rchan_reader object for reading the channel. + * This function is useful only for non-VFS readers. + */ +struct rchan_reader * +add_rchan_reader(int rchan_id, int auto_consume) +{ + struct rchan *rchan = rchan_get(rchan_id); + if (rchan == NULL) + return NULL; + + return __add_rchan_reader(rchan, NULL, auto_consume, 0); +} + +/** + * add_map_reader - create a map reader for a channel + * @rchan_id: relay channel handle + * + * Returns a pointer to the reader object created, NULL if unsuccessful + * + * Creates and initializes an rchan_reader object for reading the channel. + * This function is useful only for map readers. + */ +struct rchan_reader * +add_map_reader(int rchan_id) +{ + struct rchan *rchan = rchan_get(rchan_id); + if (rchan == NULL) + return NULL; + + return __add_rchan_reader(rchan, NULL, 0, 1); +} + +/** + * __remove_rchan_reader - destroy a channel reader + * @reader: channel reader + * + * Internal - removes reader from the open readers list, and frees it. + */ +void +__remove_rchan_reader(struct rchan_reader *reader) +{ + struct list_head *p; + struct rchan_reader *found_reader = NULL; + + write_lock(&reader->rchan->open_readers_lock); + list_for_each(p, &reader->rchan->open_readers) { + found_reader = list_entry(p, struct rchan_reader, list); + if (found_reader == reader) { + list_del(&found_reader->list); + break; + } + } + write_unlock(&reader->rchan->open_readers_lock); + + if (found_reader) + kfree(found_reader); +} + +/** + * remove_rchan_reader - destroy a channel reader + * @reader: channel reader + * + * Finds and removes the given reader from the channel. This function + * is useful only for non-VFS readers. + * + * Returns 0 if successful, negative otherwise. + */ +int +remove_rchan_reader(struct rchan_reader *reader) +{ + int err = 0; + + if (reader) { + rchan_put(reader->rchan); + __remove_rchan_reader(reader); + } else + err = -EINVAL; + + return err; +} + +/** + * remove_map_reader - destroy a map reader + * @reader: channel reader + * + * Finds and removes the given map reader from the channel. This function + * is useful only for map readers. + * + * Returns 0 if successful, negative otherwise. + */ +int +remove_map_reader(struct rchan_reader *reader) +{ + return remove_rchan_reader(reader); +} + +EXPORT_SYMBOL(relay_open); +EXPORT_SYMBOL(relay_close); +EXPORT_SYMBOL(relay_reset); +EXPORT_SYMBOL(relay_reserve); +EXPORT_SYMBOL(relay_commit); +EXPORT_SYMBOL(relay_read); +EXPORT_SYMBOL(relay_write); +EXPORT_SYMBOL(relay_bytes_avail); +EXPORT_SYMBOL(relay_buffers_consumed); +EXPORT_SYMBOL(relay_bytes_consumed); +EXPORT_SYMBOL(relay_info); +EXPORT_SYMBOL(relay_discard_init_buf); + + diff -urpN -X dontdiff linux-2.6.7/fs/relayfs/relay_locking.c linux-2.6.7.relayfs/fs/relayfs/relay_locking.c --- linux-2.6.7/fs/relayfs/relay_locking.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/fs/relayfs/relay_locking.c 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,322 @@ +/* + * RelayFS locking scheme implementation. + * + * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com) + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * + * This file is released under the GPL. + */ + +#include +#include "relay_locking.h" +#include "resize.h" + +/** + * switch_buffers - switches between read and write buffers. + * @cur_time: current time. + * @cur_tsc: the TSC associated with current_time, if applicable + * @rchan: the channel + * @finalizing: if true, don't start a new buffer + * @resetting: if true, + * + * This should be called from with interrupts disabled. + */ +static void +switch_buffers(struct timeval cur_time, + u32 cur_tsc, + struct rchan *rchan, + int finalizing, + int resetting, + int finalize_buffer_only) +{ + char *chan_buf_end; + int bytes_written; + + if (!rchan->half_switch) { + bytes_written = rchan->callbacks->buffer_end(rchan->id, + cur_write_pos(rchan), write_buf_end(rchan), + cur_time, cur_tsc, using_tsc(rchan)); + if (bytes_written == 0) + rchan->unused_bytes[rchan->buf_idx % rchan->n_bufs] = + write_buf_end(rchan) - cur_write_pos(rchan); + } + + if (finalize_buffer_only) { + rchan->bufs_produced++; + return; + } + + chan_buf_end = rchan->buf + rchan->n_bufs * rchan->buf_size; + if((write_buf(rchan) + rchan->buf_size >= chan_buf_end) || resetting) + write_buf(rchan) = rchan->buf; + else + write_buf(rchan) += rchan->buf_size; + write_buf_end(rchan) = write_buf(rchan) + rchan->buf_size; + write_limit(rchan) = write_buf_end(rchan) - rchan->end_reserve; + cur_write_pos(rchan) = write_buf(rchan); + + rchan->buf_start_time = cur_time; + rchan->buf_start_tsc = cur_tsc; + + if (resetting) + rchan->buf_idx = 0; + else + rchan->buf_idx++; + rchan->buf_id++; + + if (!packet_delivery(rchan)) + rchan->unused_bytes[rchan->buf_idx % rchan->n_bufs] = 0; + + if (resetting) { + rchan->bufs_produced = rchan->bufs_produced + rchan->n_bufs; + rchan->bufs_produced -= rchan->bufs_produced % rchan->n_bufs; + rchan->bufs_consumed = rchan->bufs_produced; + rchan->bytes_consumed = 0; + update_readers_consumed(rchan, rchan->bufs_consumed, rchan->bytes_consumed); + } else if (!rchan->half_switch) + rchan->bufs_produced++; + + rchan->half_switch = 0; + + if (!finalizing) { + bytes_written = rchan->callbacks->buffer_start(rchan->id, cur_write_pos(rchan), rchan->buf_id, cur_time, cur_tsc, using_tsc(rchan)); + cur_write_pos(rchan) += bytes_written; + } +} + +/** + * locking_reserve - reserve a slot in the buffer for an event. + * @rchan: the channel + * @slot_len: the length of the slot to reserve + * @ts: variable that will receive the time the slot was reserved + * @tsc: the timestamp counter associated with time + * @err: receives the result flags + * @interrupting: if this write is interrupting another, set to non-zero + * + * Returns pointer to the beginning of the reserved slot, NULL if error. + * + * The err value contains the result flags and is an ORed combination + * of the following: + * + * RELAY_BUFFER_SWITCH_NONE - no buffer switch occurred + * RELAY_EVENT_DISCARD_NONE - event should not be discarded + * RELAY_BUFFER_SWITCH - buffer switch occurred + * RELAY_EVENT_DISCARD - event should be discarded (all buffers are full) + * RELAY_EVENT_TOO_LONG - event won't fit into even an empty buffer + */ +inline char * +locking_reserve(struct rchan *rchan, + u32 slot_len, + struct timeval *ts, + u32 *tsc, + int *err, + int *interrupting) +{ + u32 buffers_ready; + int bytes_written; + + *err = RELAY_BUFFER_SWITCH_NONE; + + if (slot_len >= rchan->buf_size) { + *err = RELAY_WRITE_DISCARD | RELAY_WRITE_TOO_LONG; + return NULL; + } + + if (rchan->initialized == 0) { + rchan->initialized = 1; + get_timestamp(&rchan->buf_start_time, + &rchan->buf_start_tsc, rchan); + rchan->unused_bytes[0] = 0; + bytes_written = rchan->callbacks->buffer_start( + rchan->id, cur_write_pos(rchan), + rchan->buf_id, rchan->buf_start_time, + rchan->buf_start_tsc, using_tsc(rchan)); + cur_write_pos(rchan) += bytes_written; + *tsc = get_time_delta(ts, rchan); + return cur_write_pos(rchan); + } + + *tsc = get_time_delta(ts, rchan); + + if (in_progress_event_size(rchan)) { + interrupted_pos(rchan) = cur_write_pos(rchan); + cur_write_pos(rchan) = in_progress_event_pos(rchan) + + in_progress_event_size(rchan) + + interrupting_size(rchan); + *interrupting = 1; + } else { + in_progress_event_pos(rchan) = cur_write_pos(rchan); + in_progress_event_size(rchan) = slot_len; + interrupting_size(rchan) = 0; + } + + if (cur_write_pos(rchan) + slot_len > write_limit(rchan)) { + if (atomic_read(&rchan->suspended) == 1) { + in_progress_event_pos(rchan) = NULL; + in_progress_event_size(rchan) = 0; + interrupting_size(rchan) = 0; + *err = RELAY_WRITE_DISCARD; + return NULL; + } + + buffers_ready = rchan->bufs_produced - rchan->bufs_consumed; + if (buffers_ready == rchan->n_bufs - 1) { + if (!mode_continuous(rchan)) { + atomic_set(&rchan->suspended, 1); + in_progress_event_pos(rchan) = NULL; + in_progress_event_size(rchan) = 0; + interrupting_size(rchan) = 0; + get_timestamp(ts, tsc, rchan); + switch_buffers(*ts, *tsc, rchan, 0, 0, 1); + recalc_time_delta(ts, tsc, rchan); + rchan->half_switch = 1; + + cur_write_pos(rchan) = write_buf_end(rchan) - 1; + *err = RELAY_BUFFER_SWITCH | RELAY_WRITE_DISCARD; + return NULL; + } + } + + get_timestamp(ts, tsc, rchan); + switch_buffers(*ts, *tsc, rchan, 0, 0, 0); + recalc_time_delta(ts, tsc, rchan); + *err = RELAY_BUFFER_SWITCH; + } + + return cur_write_pos(rchan); +} + +/** + * locking_commit - commit a reserved slot in the buffer + * @rchan: the channel + * @from: commit the length starting here + * @len: length committed + * @deliver: length committed + * @interrupting: not used + * + * Commits len bytes and calls deliver callback if applicable. + */ +inline void +locking_commit(struct rchan *rchan, + char *from, + u32 len, + int deliver, + int interrupting) +{ + cur_write_pos(rchan) += len; + + if (interrupting) { + cur_write_pos(rchan) = interrupted_pos(rchan); + interrupting_size(rchan) += len; + } else { + in_progress_event_size(rchan) = 0; + if (interrupting_size(rchan)) { + cur_write_pos(rchan) += interrupting_size(rchan); + interrupting_size(rchan) = 0; + } + } + + if (deliver) { + if (bulk_delivery(rchan)) { + u32 cur_idx = cur_write_pos(rchan) - rchan->buf; + u32 cur_bufno = cur_idx / rchan->buf_size; + from = rchan->buf + cur_bufno * rchan->buf_size; + len = cur_idx - cur_bufno * rchan->buf_size; + } + rchan->callbacks->deliver(rchan->id, from, len); + expand_check(rchan); + } +} + +/** + * locking_finalize: - finalize last buffer at end of channel use + * @rchan: the channel + */ +inline void +locking_finalize(struct rchan *rchan) +{ + unsigned long int flags; + struct timeval time; + u32 tsc; + + local_irq_save(flags); + get_timestamp(&time, &tsc, rchan); + switch_buffers(time, tsc, rchan, 1, 0, 0); + local_irq_restore(flags); +} + +/** + * locking_get_offset - get current and max 'file' offsets for VFS + * @rchan: the channel + * @max_offset: maximum channel offset + * + * Returns the current and maximum buffer offsets in VFS terms. + */ +u32 +locking_get_offset(struct rchan *rchan, + u32 *max_offset) +{ + if (max_offset) + *max_offset = rchan->buf_size * rchan->n_bufs - 1; + + return cur_write_pos(rchan) - rchan->buf; +} + +/** + * locking_reset - reset the channel + * @rchan: the channel + * @init: 1 if this is a first-time channel initialization + */ +void locking_reset(struct rchan *rchan, int init) +{ + if (init) + channel_lock(rchan) = SPIN_LOCK_UNLOCKED; + write_buf(rchan) = rchan->buf; + write_buf_end(rchan) = write_buf(rchan) + rchan->buf_size; + cur_write_pos(rchan) = write_buf(rchan); + write_limit(rchan) = write_buf_end(rchan) - rchan->end_reserve; + in_progress_event_pos(rchan) = NULL; + in_progress_event_size(rchan) = 0; + interrupted_pos(rchan) = NULL; + interrupting_size(rchan) = 0; +} + +/** + * locking_reset_index - atomically set channel index to the beginning + * @rchan: the channel + * + * If this fails, it means that something else just logged something + * and therefore we probably no longer want to do this. It's up to the + * caller anyway... + * + * Returns 0 if the index was successfully set, negative otherwise + */ +int +locking_reset_index(struct rchan *rchan, u32 old_idx) +{ + unsigned long flags; + struct timeval time; + u32 tsc; + u32 cur_idx; + + relay_lock_channel(rchan, flags); + cur_idx = locking_get_offset(rchan, NULL); + if (cur_idx != old_idx) { + relay_unlock_channel(rchan, flags); + return -1; + } + + get_timestamp(&time, &tsc, rchan); + switch_buffers(time, tsc, rchan, 0, 1, 0); + + relay_unlock_channel(rchan, flags); + + return 0; +} + + + + + + + diff -urpN -X dontdiff linux-2.6.7/fs/relayfs/relay_locking.h linux-2.6.7.relayfs/fs/relayfs/relay_locking.h --- linux-2.6.7/fs/relayfs/relay_locking.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/fs/relayfs/relay_locking.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,34 @@ +#ifndef _RELAY_LOCKING_H +#define _RELAY_LOCKING_H + +extern char * +locking_reserve(struct rchan *rchan, + u32 slot_len, + struct timeval *time_stamp, + u32 *tsc, + int *err, + int *interrupting); + +extern void +locking_commit(struct rchan *rchan, + char *from, + u32 len, + int deliver, + int interrupting); + +extern void +locking_resume(struct rchan *rchan); + +extern void +locking_finalize(struct rchan *rchan); + +extern u32 +locking_get_offset(struct rchan *rchan, u32 *max_offset); + +extern void +locking_reset(struct rchan *rchan, int init); + +extern int +locking_reset_index(struct rchan *rchan, u32 old_idx); + +#endif /* _RELAY_LOCKING_H */ diff -urpN -X dontdiff linux-2.6.7/fs/relayfs/relay_lockless.c linux-2.6.7.relayfs/fs/relayfs/relay_lockless.c --- linux-2.6.7/fs/relayfs/relay_lockless.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/fs/relayfs/relay_lockless.c 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,541 @@ +/* + * RelayFS lockless scheme implementation. + * + * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com) + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * Copyright (C) 2002, 2003 - Bob Wisniewski (bob@watson.ibm.com), IBM Corp + * + * This file is released under the GPL. + */ + +#include +#include "relay_lockless.h" +#include "resize.h" + +/** + * compare_and_store_volatile - self-explicit + * @ptr: ptr to the word that will receive the new value + * @oval: the value we think is currently in *ptr + * @nval: the value *ptr will get if we were right + */ +inline int +compare_and_store_volatile(volatile u32 *ptr, + u32 oval, + u32 nval) +{ + u32 prev; + + barrier(); + prev = cmpxchg(ptr, oval, nval); + barrier(); + + return (prev == oval); +} + +/** + * atomic_set_volatile - atomically set the value in ptr to nval. + * @ptr: ptr to the word that will receive the new value + * @nval: the new value + */ +inline void +atomic_set_volatile(atomic_t *ptr, + u32 nval) +{ + barrier(); + atomic_set(ptr, (int)nval); + barrier(); +} + +/** + * atomic_add_volatile - atomically add val to the value at ptr. + * @ptr: ptr to the word that will receive the addition + * @val: the value to add to *ptr + */ +inline void +atomic_add_volatile(atomic_t *ptr, u32 val) +{ + barrier(); + atomic_add((int)val, ptr); + barrier(); +} + +/** + * atomic_sub_volatile - atomically substract val from the value at ptr. + * @ptr: ptr to the word that will receive the subtraction + * @val: the value to subtract from *ptr + */ +inline void +atomic_sub_volatile(atomic_t *ptr, s32 val) +{ + barrier(); + atomic_sub((int)val, ptr); + barrier(); +} + +/** + * lockless_commit - commit a reserved slot in the buffer + * @rchan: the channel + * @from: commit the length starting here + * @len: length committed + * @deliver: length committed + * @interrupting: not used + * + * Commits len bytes and calls deliver callback if applicable. + */ +inline void +lockless_commit(struct rchan *rchan, + char *from, + u32 len, + int deliver, + int interrupting) +{ + u32 bufno, idx; + + idx = from - rchan->buf; + + if (len > 0) { + bufno = RELAY_BUFNO_GET(idx, offset_bits(rchan)); + atomic_add_volatile(&fill_count(rchan, bufno), len); + } + + if (deliver) { + u32 mask = offset_mask(rchan); + if (bulk_delivery(rchan)) { + from = rchan->buf + RELAY_BUF_OFFSET_CLEAR(idx, mask); + len += RELAY_BUF_OFFSET_GET(idx, mask); + } + rchan->callbacks->deliver(rchan->id, from, len); + expand_check(rchan); + } +} + +/** + * get_buffer_end - get the address of the end of buffer + * @rchan: the channel + * @buf_idx: index into channel corresponding to address + */ +static inline char * +get_buffer_end(struct rchan *rchan, u32 buf_idx) +{ + return rchan->buf + + RELAY_BUF_OFFSET_CLEAR(buf_idx, offset_mask(rchan)) + + RELAY_BUF_SIZE(offset_bits(rchan)); +} + + +/** + * finalize_buffer - utility function consolidating end-of-buffer tasks. + * @rchan: the channel + * @end_idx: index into buffer to write the end-buffer event at + * @size_lost: number of unused bytes at the end of the buffer + * @time_stamp: the time of the end-buffer event + * @tsc: the timestamp counter associated with time + * @resetting: are we resetting the channel? + * + * This function must be called with local irqs disabled. + */ +static inline void +finalize_buffer(struct rchan *rchan, + u32 end_idx, + u32 size_lost, + struct timeval *time_stamp, + u32 *tsc, + int resetting) +{ + char* cur_write_pos; + char* write_buf_end; + u32 bufno; + int bytes_written; + + cur_write_pos = rchan->buf + end_idx; + write_buf_end = get_buffer_end(rchan, end_idx - 1); + + bytes_written = rchan->callbacks->buffer_end(rchan->id, cur_write_pos, + write_buf_end, *time_stamp, *tsc, using_tsc(rchan)); + if (bytes_written == 0) + rchan->unused_bytes[rchan->buf_idx % rchan->n_bufs] = size_lost; + + bufno = RELAY_BUFNO_GET(end_idx, offset_bits(rchan)); + atomic_add_volatile(&fill_count(rchan, bufno), size_lost); + if (resetting) { + rchan->bufs_produced = rchan->bufs_produced + rchan->n_bufs; + rchan->bufs_produced -= rchan->bufs_produced % rchan->n_bufs; + rchan->bufs_consumed = rchan->bufs_produced; + rchan->bytes_consumed = 0; + update_readers_consumed(rchan, rchan->bufs_consumed, rchan->bytes_consumed); + } else + rchan->bufs_produced++; +} + +/** + * lockless_finalize: - finalize last buffer at end of channel use + * @rchan: the channel + */ +inline void +lockless_finalize(struct rchan *rchan) +{ + u32 event_end_idx; + u32 size_lost; + unsigned long int flags; + struct timeval time; + u32 tsc; + + event_end_idx = RELAY_BUF_OFFSET_GET(idx(rchan), offset_mask(rchan)); + size_lost = RELAY_BUF_SIZE(offset_bits(rchan)) - event_end_idx; + + local_irq_save(flags); + get_timestamp(&time, &tsc, rchan); + finalize_buffer(rchan, idx(rchan) & idx_mask(rchan), size_lost, + &time, &tsc, 0); + local_irq_restore(flags); +} + +/** + * discard_check: - determine whether a write should be discarded + * @rchan: the channel + * @old_idx: index into buffer where check for space should begin + * @write_len: the length of the write to check + * @time_stamp: the time of the end-buffer event + * @tsc: the timestamp counter associated with time + * + * The return value contains the result flags and is an ORed combination + * of the following: + * + * RELAY_WRITE_DISCARD_NONE - write should not be discarded + * RELAY_BUFFER_SWITCH - buffer switch occurred + * RELAY_WRITE_DISCARD - write should be discarded (all buffers are full) + * RELAY_WRITE_TOO_LONG - write won't fit into even an empty buffer + */ +static inline int +discard_check(struct rchan *rchan, + u32 old_idx, + u32 write_len, + struct timeval *time_stamp, + u32 *tsc) +{ + u32 buffers_ready; + u32 offset_mask = offset_mask(rchan); + u8 offset_bits = offset_bits(rchan); + u32 idx_mask = idx_mask(rchan); + u32 size_lost; + unsigned long int flags; + + if (write_len > RELAY_BUF_SIZE(offset_bits)) + return RELAY_WRITE_DISCARD | RELAY_WRITE_TOO_LONG; + + if (mode_continuous(rchan)) + return RELAY_WRITE_DISCARD_NONE; + + local_irq_save(flags); + if (atomic_read(&rchan->suspended) == 1) { + local_irq_restore(flags); + return RELAY_WRITE_DISCARD; + } + if (rchan->half_switch) { + local_irq_restore(flags); + return RELAY_WRITE_DISCARD_NONE; + } + buffers_ready = rchan->bufs_produced - rchan->bufs_consumed; + if (buffers_ready == rchan->n_bufs - 1) { + atomic_set(&rchan->suspended, 1); + size_lost = RELAY_BUF_SIZE(offset_bits) + - RELAY_BUF_OFFSET_GET(old_idx, offset_mask); + finalize_buffer(rchan, old_idx & idx_mask, size_lost, + time_stamp, tsc, 0); + rchan->half_switch = 1; + idx(rchan) = RELAY_BUF_OFFSET_CLEAR((old_idx & idx_mask), offset_mask(rchan)) + RELAY_BUF_SIZE(offset_bits) - 1; + local_irq_restore(flags); + + return RELAY_BUFFER_SWITCH | RELAY_WRITE_DISCARD; + } + local_irq_restore(flags); + + return RELAY_WRITE_DISCARD_NONE; +} + +/** + * switch_buffers - switch over to a new sub-buffer + * @rchan: the channel + * @slot_len: the length of the slot needed for the current write + * @offset: the offset calculated for the new index + * @ts: timestamp + * @tsc: the timestamp counter associated with time + * @old_idx: the value of the buffer control index when we were called + * @old_idx: the new calculated value of the buffer control index + * @resetting: are we resetting the channel? + */ +static inline void +switch_buffers(struct rchan *rchan, + u32 slot_len, + u32 offset, + struct timeval *ts, + u32 *tsc, + u32 new_idx, + u32 old_idx, + int resetting) +{ + u32 size_lost = rchan->end_reserve; + unsigned long int flags; + u32 idx_mask = idx_mask(rchan); + u8 offset_bits = offset_bits(rchan); + char *cur_write_pos; + u32 new_buf_no; + u32 start_reserve = rchan->start_reserve; + + if (resetting) + size_lost = RELAY_BUF_SIZE(offset_bits(rchan)) - old_idx % rchan->buf_size; + + if (offset > 0) + size_lost += slot_len - offset; + else + old_idx += slot_len; + + local_irq_save(flags); + if (!rchan->half_switch) + finalize_buffer(rchan, old_idx & idx_mask, size_lost, + ts, tsc, resetting); + rchan->half_switch = 0; + rchan->buf_start_time = *ts; + rchan->buf_start_tsc = *tsc; + local_irq_restore(flags); + + cur_write_pos = rchan->buf + RELAY_BUF_OFFSET_CLEAR((new_idx + & idx_mask), offset_mask(rchan)); + if (resetting) + rchan->buf_idx = 0; + else + rchan->buf_idx++; + rchan->buf_id++; + + rchan->unused_bytes[rchan->buf_idx % rchan->n_bufs] = 0; + + rchan->callbacks->buffer_start(rchan->id, cur_write_pos, + rchan->buf_id, *ts, *tsc, using_tsc(rchan)); + new_buf_no = RELAY_BUFNO_GET(new_idx & idx_mask, offset_bits); + atomic_sub_volatile(&fill_count(rchan, new_buf_no), + RELAY_BUF_SIZE(offset_bits) - start_reserve); + if (atomic_read(&fill_count(rchan, new_buf_no)) < start_reserve) + atomic_set_volatile(&fill_count(rchan, new_buf_no), + start_reserve); +} + +/** + * lockless_reserve_slow - the slow reserve path in the lockless scheme + * @rchan: the channel + * @slot_len: the length of the slot to reserve + * @ts: variable that will receive the time the slot was reserved + * @tsc: the timestamp counter associated with time + * @old_idx: the value of the buffer control index when we were called + * @err: receives the result flags + * + * Returns pointer to the beginning of the reserved slot, NULL if error. + + * err values same as for lockless_reserve. + */ +static inline char * +lockless_reserve_slow(struct rchan *rchan, + u32 slot_len, + struct timeval *ts, + u32 *tsc, + u32 old_idx, + int *err) +{ + u32 new_idx, offset; + unsigned long int flags; + u32 offset_mask = offset_mask(rchan); + u32 idx_mask = idx_mask(rchan); + u32 start_reserve = rchan->start_reserve; + u32 end_reserve = rchan->end_reserve; + int discard_event; + u32 reserved_idx; + char *cur_write_pos; + int initializing = 0; + + *err = RELAY_BUFFER_SWITCH_NONE; + + discard_event = discard_check(rchan, old_idx, slot_len, ts, tsc); + if (discard_event != RELAY_WRITE_DISCARD_NONE) { + *err = discard_event; + return NULL; + } + + local_irq_save(flags); + if (rchan->initialized == 0) { + rchan->initialized = initializing = 1; + idx(rchan) = rchan->start_reserve + rchan->rchan_start_reserve; + } + local_irq_restore(flags); + + do { + old_idx = idx(rchan); + new_idx = old_idx + slot_len; + + offset = RELAY_BUF_OFFSET_GET(new_idx + end_reserve, + offset_mask); + if ((offset < slot_len) && (offset > 0)) { + reserved_idx = RELAY_BUF_OFFSET_CLEAR(new_idx + + end_reserve, offset_mask) + start_reserve; + new_idx = reserved_idx + slot_len; + } else if (offset < slot_len) { + reserved_idx = old_idx; + new_idx = RELAY_BUF_OFFSET_CLEAR(new_idx + + end_reserve, offset_mask) + start_reserve; + } else + reserved_idx = old_idx; + get_timestamp(ts, tsc, rchan); + } while (!compare_and_store_volatile(&idx(rchan), old_idx, new_idx)); + + reserved_idx &= idx_mask; + + if (initializing == 1) { + cur_write_pos = rchan->buf + + RELAY_BUF_OFFSET_CLEAR((old_idx & idx_mask), + offset_mask(rchan)); + rchan->buf_start_time = *ts; + rchan->buf_start_tsc = *tsc; + rchan->unused_bytes[0] = 0; + + rchan->callbacks->buffer_start(rchan->id, cur_write_pos, + rchan->buf_id, *ts, *tsc, using_tsc(rchan)); + } + + if (offset < slot_len) { + switch_buffers(rchan, slot_len, offset, ts, tsc, new_idx, + old_idx, 0); + *err = RELAY_BUFFER_SWITCH; + } + + /* If not using TSC, need to calc time delta */ + recalc_time_delta(ts, tsc, rchan); + + return rchan->buf + reserved_idx; +} + +/** + * lockless_reserve - reserve a slot in the buffer for an event. + * @rchan: the channel + * @slot_len: the length of the slot to reserve + * @ts: variable that will receive the time the slot was reserved + * @tsc: the timestamp counter associated with time + * @err: receives the result flags + * @interrupting: not used + * + * Returns pointer to the beginning of the reserved slot, NULL if error. + * + * The err value contains the result flags and is an ORed combination + * of the following: + * + * RELAY_BUFFER_SWITCH_NONE - no buffer switch occurred + * RELAY_EVENT_DISCARD_NONE - event should not be discarded + * RELAY_BUFFER_SWITCH - buffer switch occurred + * RELAY_EVENT_DISCARD - event should be discarded (all buffers are full) + * RELAY_EVENT_TOO_LONG - event won't fit into even an empty buffer + */ +inline char * +lockless_reserve(struct rchan *rchan, + u32 slot_len, + struct timeval *ts, + u32 *tsc, + int *err, + int *interrupting) +{ + u32 old_idx, new_idx, offset; + u32 offset_mask = offset_mask(rchan); + + do { + old_idx = idx(rchan); + new_idx = old_idx + slot_len; + + offset = RELAY_BUF_OFFSET_GET(new_idx + rchan->end_reserve, + offset_mask); + if (offset < slot_len) + return lockless_reserve_slow(rchan, slot_len, + ts, tsc, old_idx, err); + get_time_or_tsc(ts, tsc, rchan); + } while (!compare_and_store_volatile(&idx(rchan), old_idx, new_idx)); + + /* If not using TSC, need to calc time delta */ + recalc_time_delta(ts, tsc, rchan); + + *err = RELAY_BUFFER_SWITCH_NONE; + + return rchan->buf + (old_idx & idx_mask(rchan)); +} + +/** + * lockless_get_offset - get current and max channel offsets + * @rchan: the channel + * @max_offset: maximum channel offset + * + * Returns the current and maximum channel offsets. + */ +u32 +lockless_get_offset(struct rchan *rchan, + u32 *max_offset) +{ + if (max_offset) + *max_offset = rchan->buf_size * rchan->n_bufs - 1; + + return rchan->initialized ? idx(rchan) & idx_mask(rchan) : 0; +} + +/** + * lockless_reset - reset the channel + * @rchan: the channel + * @init: 1 if this is a first-time channel initialization + */ +void lockless_reset(struct rchan *rchan, int init) +{ + int i; + + /* Start first buffer at 0 - (end_reserve + 1) so that it + gets initialized via buffer_start callback as well. */ + idx(rchan) = 0UL - (rchan->end_reserve + 1); + idx_mask(rchan) = + (1UL << (bufno_bits(rchan) + offset_bits(rchan))) - 1; + atomic_set(&fill_count(rchan, 0), + (int)rchan->start_reserve + + (int)rchan->rchan_start_reserve); + for (i = 1; i < rchan->n_bufs; i++) + atomic_set(&fill_count(rchan, i), + (int)RELAY_BUF_SIZE(offset_bits(rchan))); +} + +/** + * lockless_reset_index - atomically set channel index to the beginning + * @rchan: the channel + * @old_idx: the current index + * + * If this fails, it means that something else just logged something + * and therefore we probably no longer want to do this. It's up to the + * caller anyway... + * + * Returns 0 if the index was successfully set, negative otherwise + */ +int +lockless_reset_index(struct rchan *rchan, u32 old_idx) +{ + struct timeval ts; + u32 tsc; + u32 new_idx; + + if (compare_and_store_volatile(&idx(rchan), old_idx, 0)) { + new_idx = rchan->start_reserve; + switch_buffers(rchan, 0, 0, &ts, &tsc, new_idx, old_idx, 1); + return 0; + } else + return -1; +} + + + + + + + + + + + + + diff -urpN -X dontdiff linux-2.6.7/fs/relayfs/relay_lockless.h linux-2.6.7.relayfs/fs/relayfs/relay_lockless.h --- linux-2.6.7/fs/relayfs/relay_lockless.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/fs/relayfs/relay_lockless.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,34 @@ +#ifndef _RELAY_LOCKLESS_H +#define _RELAY_LOCKLESS_H + +extern char * +lockless_reserve(struct rchan *rchan, + u32 slot_len, + struct timeval *time_stamp, + u32 *tsc, + int * interrupting, + int * errcode); + +extern void +lockless_commit(struct rchan *rchan, + char * from, + u32 len, + int deliver, + int interrupting); + +extern void +lockless_resume(struct rchan *rchan); + +extern void +lockless_finalize(struct rchan *rchan); + +extern u32 +lockless_get_offset(struct rchan *rchan, u32 *max_offset); + +extern void +lockless_reset(struct rchan *rchan, int init); + +extern int +lockless_reset_index(struct rchan *rchan, u32 old_idx); + +#endif/* _RELAY_LOCKLESS_H */ diff -urpN -X dontdiff linux-2.6.7/fs/relayfs/resize.c linux-2.6.7.relayfs/fs/relayfs/resize.c --- linux-2.6.7/fs/relayfs/resize.c 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/fs/relayfs/resize.c 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,1104 @@ +/* + * RelayFS buffer management and resizing code. + * + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com) + * + * This file is released under the GPL. + */ + +#include +#include +#include +#include +#include "resize.h" + +/** + * alloc_page_array - alloc array to hold pages, but not pages + * @size: the total size of the memory represented by the page array + * @page_count: the number of pages the array can hold + * @err: 0 on success, negative otherwise + * + * Returns a pointer to the page array if successful, NULL otherwise. + */ +static struct page ** +alloc_page_array(int size, int *page_count, int *err) +{ + int n_pages; + struct page **page_array; + int page_array_size; + + *err = 0; + + size = PAGE_ALIGN(size); + n_pages = size >> PAGE_SHIFT; + page_array_size = n_pages * sizeof(struct page *); + page_array = kmalloc(page_array_size, GFP_KERNEL); + if (page_array == NULL) { + *err = -ENOMEM; + return NULL; + } + *page_count = n_pages; + memset(page_array, 0, page_array_size); + + return page_array; +} + +/** + * free_page_array - free array to hold pages, but not pages + * @page_array: pointer to the page array + */ +static inline void +free_page_array(struct page **page_array) +{ + kfree(page_array); +} + +/** + * depopulate_page_array - free and unreserve all pages in the array + * @page_array: pointer to the page array + * @page_count: number of pages to free + */ +static void +depopulate_page_array(struct page **page_array, int page_count) +{ + int i; + + for (i = 0; i < page_count; i++) { + ClearPageReserved(page_array[i]); + __free_page(page_array[i]); + } +} + +/** + * populate_page_array - allocate and reserve pages + * @page_array: pointer to the page array + * @page_count: number of pages to allocate + * + * Returns 0 if successful, negative otherwise. + */ +static int +populate_page_array(struct page **page_array, int page_count) +{ + int i; + + for (i = 0; i < page_count; i++) { + page_array[i] = alloc_page(GFP_KERNEL); + if (unlikely(!page_array[i])) { + depopulate_page_array(page_array, i); + return -ENOMEM; + } + SetPageReserved(page_array[i]); + } + return 0; +} + +/** + * alloc_rchan_buf - allocate the initial channel buffer + * @size: total size of the buffer + * @page_array: receives a pointer to the buffer's page array + * @page_count: receives the number of pages allocated + * + * Returns a pointer to the resulting buffer, NULL if unsuccessful + */ +void * +alloc_rchan_buf(unsigned long size, struct page ***page_array, int *page_count) +{ + void *mem; + int err; + + *page_array = alloc_page_array(size, page_count, &err); + if (!*page_array) + return NULL; + + err = populate_page_array(*page_array, *page_count); + if (err) { + free_page_array(*page_array); + *page_array = NULL; + return NULL; + } + + mem = vmap(*page_array, *page_count, GFP_KERNEL, PAGE_KERNEL); + if (!mem) { + depopulate_page_array(*page_array, *page_count); + free_page_array(*page_array); + *page_array = NULL; + return NULL; + } + memset(mem, 0, size); + + return mem; +} + +/** + * expand_check - check whether the channel needs expanding + * @rchan: the channel + * + * If the channel needs expanding, the needs_resize callback is + * called with RELAY_RESIZE_EXPAND. + * + * Returns the suggested number of sub-buffers for the new + * buffer. + */ +void +expand_check(struct rchan *rchan) +{ + u32 active_bufs; + u32 new_n_bufs = 0; + u32 threshold = rchan->n_bufs * RESIZE_THRESHOLD; + + if (rchan->init_buf) + return; + + if (rchan->resize_min == 0) + return; + + if (rchan->resizing || rchan->replace_buffer) + return; + + active_bufs = rchan->bufs_produced - rchan->bufs_consumed + 1; + + if (rchan->resize_max && active_bufs == threshold) { + new_n_bufs = rchan->n_bufs * 2; + } + + if (new_n_bufs && (new_n_bufs * rchan->buf_size <= rchan->resize_max)) + rchan->callbacks->needs_resize(rchan->id, + RELAY_RESIZE_EXPAND, + rchan->buf_size, + new_n_bufs); +} + +/** + * can_shrink - check whether the channel can shrink + * @rchan: the channel + * @cur_idx: the current channel index + * + * Returns the suggested number of sub-buffers for the new + * buffer, 0 if the buffer is not shrinkable. + */ +static inline u32 +can_shrink(struct rchan *rchan, u32 cur_idx) +{ + u32 active_bufs = rchan->bufs_produced - rchan->bufs_consumed + 1; + u32 new_n_bufs = 0; + u32 cur_bufno_bytes = cur_idx % rchan->buf_size; + + if (rchan->resize_min == 0 || + rchan->resize_min >= rchan->n_bufs * rchan->buf_size) + goto out; + + if (active_bufs > 1) + goto out; + + if (cur_bufno_bytes != rchan->bytes_consumed) + goto out; + + new_n_bufs = rchan->resize_min / rchan->buf_size; +out: + return new_n_bufs; +} + +/** + * shrink_check: - timer function checking whether the channel can shrink + * @data: unused + * + * Every SHRINK_TIMER_SECS, check whether the channel is shrinkable. + * If so, we attempt to atomically reset the channel to the beginning. + * The needs_resize callback is then called with RELAY_RESIZE_SHRINK. + * If the reset fails, it means we really shouldn't be shrinking now + * and need to wait until the next time around. + */ +static void +shrink_check(unsigned long data) +{ + struct rchan *rchan = (struct rchan *)data; + u32 shrink_to_nbufs, cur_idx; + + del_timer(&rchan->shrink_timer); + rchan->shrink_timer.expires = jiffies + SHRINK_TIMER_SECS * HZ; + add_timer(&rchan->shrink_timer); + + if (rchan->init_buf) + return; + + if (rchan->resizing || rchan->replace_buffer) + return; + + if (using_lockless(rchan)) + cur_idx = idx(rchan); + else + cur_idx = relay_get_offset(rchan, NULL); + + shrink_to_nbufs = can_shrink(rchan, cur_idx); + if (shrink_to_nbufs != 0 && reset_index(rchan, cur_idx) == 0) { + update_readers_consumed(rchan, rchan->bufs_consumed, 0); + rchan->callbacks->needs_resize(rchan->id, + RELAY_RESIZE_SHRINK, + rchan->buf_size, + shrink_to_nbufs); + } +} + +/** + * init_shrink_timer: - Start timer used to check shrinkability. + * @rchan: the channel + */ +void +init_shrink_timer(struct rchan *rchan) +{ + if (rchan->resize_min) { + init_timer(&rchan->shrink_timer); + rchan->shrink_timer.function = shrink_check; + rchan->shrink_timer.data = (unsigned long)rchan; + rchan->shrink_timer.expires = jiffies + SHRINK_TIMER_SECS * HZ; + add_timer(&rchan->shrink_timer); + } +} + + +/** + * alloc_new_pages - allocate new pages for expanding buffer + * @rchan: the channel + * + * Returns 0 on success, negative otherwise. + */ +static int +alloc_new_pages(struct rchan *rchan) +{ + int new_pages_size, err; + + if (unlikely(rchan->expand_page_array)) BUG(); + + new_pages_size = rchan->resize_alloc_size - rchan->alloc_size; + rchan->expand_page_array = alloc_page_array(new_pages_size, + &rchan->expand_page_count, &err); + if (rchan->expand_page_array == NULL) { + rchan->resize_err = -ENOMEM; + return -ENOMEM; + } + + err = populate_page_array(rchan->expand_page_array, + rchan->expand_page_count); + if (err) { + rchan->resize_err = -ENOMEM; + free_page_array(rchan->expand_page_array); + rchan->expand_page_array = NULL; + } + + return err; +} + +/** + * clear_resize_offset - helper function for buffer resizing + * @rchan: the channel + * + * Clear the saved offset change. + */ +static inline void +clear_resize_offset(struct rchan *rchan) +{ + rchan->resize_offset.ge = 0UL; + rchan->resize_offset.le = 0UL; + rchan->resize_offset.delta = 0; +} + +/** + * save_resize_offset - helper function for buffer resizing + * @rchan: the channel + * @ge: affected region ge this + * @le: affected region le this + * @delta: apply this delta + * + * Save a resize offset. + */ +static inline void +save_resize_offset(struct rchan *rchan, u32 ge, u32 le, int delta) +{ + rchan->resize_offset.ge = ge; + rchan->resize_offset.le = le; + rchan->resize_offset.delta = delta; +} + +/** + * update_file_offset - apply offset change to reader + * @reader: the channel reader + * @change_idx: the offset index into the offsets array + * + * Returns non-zero if the offset was applied. + * + * Apply the offset delta saved in change_idx to the reader's + * current read position. + */ +static inline int +update_file_offset(struct rchan_reader *reader) +{ + int applied = 0; + struct rchan *rchan = reader->rchan; + u32 f_pos; + int delta = reader->rchan->resize_offset.delta; + + if (reader->vfs_reader) + f_pos = (u32)reader->pos.file->f_pos; + else + f_pos = reader->pos.f_pos; + + if (f_pos == relay_get_offset(rchan, NULL)) + return 0; + + if ((f_pos >= rchan->resize_offset.ge - 1) && + (f_pos <= rchan->resize_offset.le)) { + if (reader->vfs_reader) { + if (reader->rchan->read_start == f_pos) + reader->rchan->read_start += delta; + reader->pos.file->f_pos += delta; + } else + reader->pos.f_pos += delta; + applied = 1; + } + + return applied; +} + +/** + * update_file_offsets - apply offset change to readers + * @rchan: the channel + * + * Apply the saved offset deltas to all files open on the channel. + */ +static inline void +update_file_offsets(struct rchan *rchan) +{ + struct list_head *p; + struct rchan_reader *reader; + + read_lock(&rchan->open_readers_lock); + list_for_each(p, &rchan->open_readers) { + reader = list_entry(p, struct rchan_reader, list); + if (update_file_offset(reader)) + reader->offset_changed = 1; + } + read_unlock(&rchan->open_readers_lock); +} + +/** + * setup_expand_buf - setup expand buffer for replacement + * @rchan: the channel + * @newsize: the size of the new buffer + * @oldsize: the size of the old buffer + * @old_n_bufs: the number of sub-buffers in the old buffer + * + * Inserts new pages into the old buffer to create a larger + * new channel buffer, splitting them at old_cur_idx, the bottom + * half of the old buffer going to the bottom of the new, likewise + * for the top half. + */ +static void +setup_expand_buf(struct rchan *rchan, int newsize, int oldsize, u32 old_n_bufs) +{ + u32 cur_idx; + int cur_bufno, delta, i, j; + u32 ge, le; + int cur_pageno; + u32 free_bufs, free_pages; + u32 free_pages_in_cur_buf; + u32 free_bufs_to_end; + u32 cur_pages = rchan->alloc_size >> PAGE_SHIFT; + u32 pages_per_buf = cur_pages / rchan->n_bufs; + u32 bufs_ready = rchan->bufs_produced - rchan->bufs_consumed; + + if (!rchan->resize_page_array || !rchan->expand_page_array || + !rchan->buf_page_array) + return; + + if (bufs_ready >= rchan->n_bufs) { + bufs_ready = rchan->n_bufs; + free_bufs = 0; + } else + free_bufs = rchan->n_bufs - bufs_ready - 1; + + cur_idx = relay_get_offset(rchan, NULL); + cur_pageno = cur_idx / PAGE_SIZE; + cur_bufno = cur_idx / rchan->buf_size; + + free_pages_in_cur_buf = (pages_per_buf - 1) - (cur_pageno % pages_per_buf); + free_pages = free_bufs * pages_per_buf + free_pages_in_cur_buf; + free_bufs_to_end = (rchan->n_bufs - 1) - cur_bufno; + if (free_bufs >= free_bufs_to_end) { + free_pages = free_bufs_to_end * pages_per_buf + free_pages_in_cur_buf; + free_bufs = free_bufs_to_end; + } + + for (i = 0, j = 0; i <= cur_pageno + free_pages; i++, j++) + rchan->resize_page_array[j] = rchan->buf_page_array[i]; + for (i = 0; i < rchan->expand_page_count; i++, j++) + rchan->resize_page_array[j] = rchan->expand_page_array[i]; + for (i = cur_pageno + free_pages + 1; i < rchan->buf_page_count; i++, j++) + rchan->resize_page_array[j] = rchan->buf_page_array[i]; + + delta = newsize - oldsize; + ge = (cur_pageno + 1 + free_pages) * PAGE_SIZE; + le = oldsize; + save_resize_offset(rchan, ge, le, delta); + + rchan->expand_buf_id = rchan->buf_id + 1 + free_bufs; +} + +/** + * setup_shrink_buf - setup shrink buffer for replacement + * @rchan: the channel + * + * Removes pages from the old buffer to create a smaller + * new channel buffer. + */ +static void +setup_shrink_buf(struct rchan *rchan) +{ + int i; + int copy_end_page; + + if (!rchan->resize_page_array || !rchan->shrink_page_array || + !rchan->buf_page_array) + return; + + copy_end_page = rchan->resize_alloc_size / PAGE_SIZE; + + for (i = 0; i < copy_end_page; i++) + rchan->resize_page_array[i] = rchan->buf_page_array[i]; +} + +/** + * cleanup_failed_alloc - relaybuf_alloc helper + */ +static void +cleanup_failed_alloc(struct rchan *rchan) +{ + if (rchan->expand_page_array) { + depopulate_page_array(rchan->expand_page_array, + rchan->expand_page_count); + free_page_array(rchan->expand_page_array); + rchan->expand_page_array = NULL; + rchan->expand_page_count = 0; + } else if (rchan->shrink_page_array) { + free_page_array(rchan->shrink_page_array); + rchan->shrink_page_array = NULL; + rchan->shrink_page_count = 0; + } + + if (rchan->resize_page_array) { + free_page_array(rchan->resize_page_array); + rchan->resize_page_array = NULL; + rchan->resize_page_count = 0; + } +} + +/** + * relaybuf_alloc - allocate a new resized channel buffer + * @private: pointer to the channel struct + * + * Internal - manages the allocation and remapping of new channel + * buffers. + */ +static void +relaybuf_alloc(void *private) +{ + struct rchan *rchan = (struct rchan *)private; + int i, j, err; + u32 old_cur_idx; + int free_size; + int free_start_page, free_end_page; + u32 newsize, oldsize; + + if (rchan->resize_alloc_size > rchan->alloc_size) { + err = alloc_new_pages(rchan); + if (err) goto cleanup; + } else { + free_size = rchan->alloc_size - rchan->resize_alloc_size; + BUG_ON(free_size <= 0); + rchan->shrink_page_array = alloc_page_array(free_size, + &rchan->shrink_page_count, &err); + if (rchan->shrink_page_array == NULL) + goto cleanup; + free_start_page = rchan->resize_alloc_size / PAGE_SIZE; + free_end_page = rchan->alloc_size / PAGE_SIZE; + for (i = 0, j = free_start_page; j < free_end_page; i++, j++) + rchan->shrink_page_array[i] = rchan->buf_page_array[j]; + } + + rchan->resize_page_array = alloc_page_array(rchan->resize_alloc_size, + &rchan->resize_page_count, &err); + if (rchan->resize_page_array == NULL) + goto cleanup; + + old_cur_idx = relay_get_offset(rchan, NULL); + clear_resize_offset(rchan); + newsize = rchan->resize_alloc_size; + oldsize = rchan->alloc_size; + if (newsize > oldsize) + setup_expand_buf(rchan, newsize, oldsize, rchan->n_bufs); + else + setup_shrink_buf(rchan); + + rchan->resize_buf = vmap(rchan->resize_page_array, rchan->resize_page_count, GFP_KERNEL, PAGE_KERNEL); + + if (rchan->resize_buf == NULL) + goto cleanup; + + rchan->replace_buffer = 1; + rchan->resizing = 0; + + rchan->callbacks->needs_resize(rchan->id, RELAY_RESIZE_REPLACE, 0, 0); + return; + +cleanup: + cleanup_failed_alloc(rchan); + rchan->resize_err = -ENOMEM; + return; +} + +/** + * relaybuf_free - free a resized channel buffer + * @private: pointer to the channel struct + * + * Internal - manages the de-allocation and unmapping of old channel + * buffers. + */ +static void +relaybuf_free(void *private) +{ + struct free_rchan_buf *free_buf = (struct free_rchan_buf *)private; + int i; + + if (free_buf->unmap_buf) + vunmap(free_buf->unmap_buf); + + for (i = 0; i < 3; i++) { + if (!free_buf->page_array[i].array) + continue; + if (free_buf->page_array[i].count) + depopulate_page_array(free_buf->page_array[i].array, + free_buf->page_array[i].count); + free_page_array(free_buf->page_array[i].array); + } + + kfree(free_buf); +} + +/** + * calc_order - determine the power-of-2 order of a resize + * @high: the larger size + * @low: the smaller size + * + * Returns order + */ +static inline int +calc_order(u32 high, u32 low) +{ + int order = 0; + + if (!high || !low || high <= low) + return 0; + + while (high > low) { + order++; + high /= 2; + } + + return order; +} + +/** + * check_size - check the sanity of the requested channel size + * @rchan: the channel + * @nbufs: the new number of sub-buffers + * @err: return code + * + * Returns the non-zero total buffer size if ok, otherwise 0 and + * sets errcode if not. + */ +static inline u32 +check_size(struct rchan *rchan, u32 nbufs, int *err) +{ + u32 new_channel_size = 0; + + *err = 0; + + if (nbufs > rchan->n_bufs) { + rchan->resize_order = calc_order(nbufs, rchan->n_bufs); + if (!rchan->resize_order) { + *err = -EINVAL; + goto out; + } + + new_channel_size = rchan->buf_size * nbufs; + if (new_channel_size > rchan->resize_max) { + *err = -EINVAL; + goto out; + } + } else if (nbufs < rchan->n_bufs) { + if (rchan->n_bufs < 2) { + *err = -EINVAL; + goto out; + } + rchan->resize_order = -calc_order(rchan->n_bufs, nbufs); + if (!rchan->resize_order) { + *err = -EINVAL; + goto out; + } + + new_channel_size = rchan->buf_size * nbufs; + if (new_channel_size < rchan->resize_min) { + *err = -EINVAL; + goto out; + } + } else + *err = -EINVAL; +out: + return new_channel_size; +} + +/** + * __relay_realloc_buffer - allocate a new channel buffer + * @rchan: the channel + * @new_nbufs: the new number of sub-buffers + * @async: do the allocation using a work queue + * + * Internal - see relay_realloc_buffer() for details. + */ +static int +__relay_realloc_buffer(struct rchan *rchan, u32 new_nbufs, int async) +{ + u32 new_channel_size; + int err = 0; + + if (new_nbufs == rchan->n_bufs) + return -EINVAL; + + if (down_trylock(&rchan->resize_sem)) + return -EBUSY; + + if (rchan->init_buf) { + err = -EPERM; + goto out; + } + + if (rchan->replace_buffer) { + err = -EBUSY; + goto out; + } + + if (rchan->resizing) { + err = -EBUSY; + goto out; + } else + rchan->resizing = 1; + + if (rchan->resize_failures > MAX_RESIZE_FAILURES) { + err = -ENOMEM; + goto out; + } + + new_channel_size = check_size(rchan, new_nbufs, &err); + if (err) + goto out; + + rchan->resize_n_bufs = new_nbufs; + rchan->resize_buf_size = rchan->buf_size; + rchan->resize_alloc_size = FIX_SIZE(new_channel_size); + + if (async) { + INIT_WORK(&rchan->work, relaybuf_alloc, rchan); + schedule_delayed_work(&rchan->work, 1); + } else + relaybuf_alloc((void *)rchan); +out: + up(&rchan->resize_sem); + + return err; +} + +/** + * relay_realloc_buffer - allocate a new channel buffer + * @rchan_id: the channel id + * @bufsize: the new sub-buffer size + * @nbufs: the new number of sub-buffers + * + * Allocates a new channel buffer using the specified sub-buffer size + * and count. If async is non-zero, the allocation is done in the + * background using a work queue. When the allocation has completed, + * the needs_resize() callback is called with a resize_type of + * RELAY_RESIZE_REPLACE. This function doesn't replace the old buffer + * with the new - see relay_replace_buffer(). See + * Documentation/filesystems/relayfs.txt for more details. + * + * Returns 0 on success, or errcode if the channel is busy or if + * the allocation couldn't happen for some reason. + */ +int +relay_realloc_buffer(int rchan_id, u32 new_nbufs, int async) +{ + int err; + + struct rchan *rchan; + + rchan = rchan_get(rchan_id); + if (rchan == NULL) + return -EBADF; + + err = __relay_realloc_buffer(rchan, new_nbufs, async); + + rchan_put(rchan); + + return err; +} + +/** + * expand_cancel_check - check whether the current expand needs canceling + * @rchan: the channel + * + * Returns 1 if the expand should be canceled, 0 otherwise. + */ +static int +expand_cancel_check(struct rchan *rchan) +{ + if (rchan->buf_id >= rchan->expand_buf_id) + return 1; + else + return 0; +} + +/** + * shrink_cancel_check - check whether the current shrink needs canceling + * @rchan: the channel + * + * Returns 1 if the shrink should be canceled, 0 otherwise. + */ +static int +shrink_cancel_check(struct rchan *rchan, u32 newsize) +{ + u32 active_bufs = rchan->bufs_produced - rchan->bufs_consumed + 1; + u32 cur_idx = relay_get_offset(rchan, NULL); + + if (cur_idx >= newsize) + return 1; + + if (active_bufs > 1) + return 1; + + return 0; +} + +/** + * switch_rchan_buf - do_replace_buffer helper + */ +static void +switch_rchan_buf(struct rchan *rchan, + int newsize, + int oldsize, + u32 old_nbufs, + u32 cur_idx) +{ + u32 newbufs, cur_bufno; + int i; + + cur_bufno = cur_idx / rchan->buf_size; + + rchan->buf = rchan->resize_buf; + rchan->alloc_size = rchan->resize_alloc_size; + rchan->n_bufs = rchan->resize_n_bufs; + + if (newsize > oldsize) { + u32 ge = rchan->resize_offset.ge; + u32 moved_buf = ge / rchan->buf_size; + + newbufs = (newsize - oldsize) / rchan->buf_size; + for (i = moved_buf; i < old_nbufs; i++) { + if (using_lockless(rchan)) + atomic_set(&fill_count(rchan, i + newbufs), + atomic_read(&fill_count(rchan, i))); + rchan->unused_bytes[i + newbufs] = rchan->unused_bytes[i]; + } + for (i = moved_buf; i < moved_buf + newbufs; i++) { + if (using_lockless(rchan)) + atomic_set(&fill_count(rchan, i), + (int)RELAY_BUF_SIZE(offset_bits(rchan))); + rchan->unused_bytes[i] = 0; + } + } + + rchan->buf_idx = cur_bufno; + + if (!using_lockless(rchan)) { + cur_write_pos(rchan) = rchan->buf + cur_idx; + write_buf(rchan) = rchan->buf + cur_bufno * rchan->buf_size; + write_buf_end(rchan) = write_buf(rchan) + rchan->buf_size; + write_limit(rchan) = write_buf_end(rchan) - rchan->end_reserve; + } else { + idx(rchan) &= idx_mask(rchan); + bufno_bits(rchan) += rchan->resize_order; + idx_mask(rchan) = + (1UL << (bufno_bits(rchan) + offset_bits(rchan))) - 1; + } +} + +/** + * do_replace_buffer - does the work of channel buffer replacement + * @rchan: the channel + * @newsize: new channel buffer size + * @oldsize: old channel buffer size + * @old_n_bufs: old channel sub-buffer count + * + * Returns 0 if replacement happened, 1 if canceled + * + * Does the work of switching buffers and fixing everything up + * so the channel can continue with a new size. + */ +static int +do_replace_buffer(struct rchan *rchan, + int newsize, + int oldsize, + u32 old_nbufs) +{ + u32 cur_idx; + int err = 0; + int canceled; + + cur_idx = relay_get_offset(rchan, NULL); + + if (newsize > oldsize) + canceled = expand_cancel_check(rchan); + else + canceled = shrink_cancel_check(rchan, newsize); + + if (canceled) { + err = -EAGAIN; + goto out; + } + + switch_rchan_buf(rchan, newsize, oldsize, old_nbufs, cur_idx); + + if (rchan->resize_offset.delta) + update_file_offsets(rchan); + + atomic_set(&rchan->suspended, 0); + + rchan->old_buf_page_array = rchan->buf_page_array; + rchan->buf_page_array = rchan->resize_page_array; + rchan->buf_page_count = rchan->resize_page_count; + rchan->resize_page_array = NULL; + rchan->resize_page_count = 0; + rchan->resize_buf = NULL; + rchan->resize_buf_size = 0; + rchan->resize_alloc_size = 0; + rchan->resize_n_bufs = 0; + rchan->resize_err = 0; + rchan->resize_order = 0; +out: + rchan->callbacks->needs_resize(rchan->id, + RELAY_RESIZE_REPLACED, + rchan->buf_size, + rchan->n_bufs); + return err; +} + +/** + * add_free_page_array - add a page_array to be freed + * @free_rchan_buf: the free_rchan_buf struct + * @page_array: the page array to free + * @page_count: the number of pages to free, 0 to free the array only + * + * Internal - Used add page_arrays to be freed asynchronously. + */ +static inline void +add_free_page_array(struct free_rchan_buf *free_rchan_buf, + struct page **page_array, int page_count) +{ + int cur = free_rchan_buf->cur++; + + free_rchan_buf->page_array[cur].array = page_array; + free_rchan_buf->page_array[cur].count = page_count; +} + +/** + * free_rchan_buf - free a channel buffer + * @buf: pointer to the buffer to free + * @page_array: pointer to the buffer's page array + * @page_count: number of pages in page array + */ +int +free_rchan_buf(void *buf, struct page **page_array, int page_count) +{ + struct free_rchan_buf *free_buf; + + free_buf = kmalloc(sizeof(struct free_rchan_buf), GFP_ATOMIC); + if (!free_buf) + return -ENOMEM; + memset(free_buf, 0, sizeof(struct free_rchan_buf)); + + free_buf->unmap_buf = buf; + add_free_page_array(free_buf, page_array, page_count); + + INIT_WORK(&free_buf->work, relaybuf_free, free_buf); + schedule_delayed_work(&free_buf->work, 1); + + return 0; +} + +/** + * free_replaced_buffer - free a channel's old buffer + * @rchan: the channel + * @oldbuf: the old buffer + * @oldsize: old buffer size + * + * Frees a channel buffer via work queue. + */ +static int +free_replaced_buffer(struct rchan *rchan, char *oldbuf, int oldsize) +{ + struct free_rchan_buf *free_buf; + + free_buf = kmalloc(sizeof(struct free_rchan_buf), GFP_ATOMIC); + if (!free_buf) + return -ENOMEM; + memset(free_buf, 0, sizeof(struct free_rchan_buf)); + + free_buf->unmap_buf = oldbuf; + add_free_page_array(free_buf, rchan->old_buf_page_array, 0); + rchan->old_buf_page_array = NULL; + add_free_page_array(free_buf, rchan->expand_page_array, 0); + add_free_page_array(free_buf, rchan->shrink_page_array, rchan->shrink_page_count); + + rchan->expand_page_array = NULL; + rchan->expand_page_count = 0; + rchan->shrink_page_array = NULL; + rchan->shrink_page_count = 0; + + INIT_WORK(&free_buf->work, relaybuf_free, free_buf); + schedule_delayed_work(&free_buf->work, 1); + + return 0; +} + +/** + * free_canceled_resize - free buffers allocated for a canceled resize + * @rchan: the channel + * + * Frees canceled buffers via work queue. + */ +static int +free_canceled_resize(struct rchan *rchan) +{ + struct free_rchan_buf *free_buf; + + free_buf = kmalloc(sizeof(struct free_rchan_buf), GFP_ATOMIC); + if (!free_buf) + return -ENOMEM; + memset(free_buf, 0, sizeof(struct free_rchan_buf)); + + if (rchan->resize_alloc_size > rchan->alloc_size) + add_free_page_array(free_buf, rchan->expand_page_array, rchan->expand_page_count); + else + add_free_page_array(free_buf, rchan->shrink_page_array, 0); + + add_free_page_array(free_buf, rchan->resize_page_array, 0); + free_buf->unmap_buf = rchan->resize_buf; + + rchan->expand_page_array = NULL; + rchan->expand_page_count = 0; + rchan->shrink_page_array = NULL; + rchan->shrink_page_count = 0; + rchan->resize_page_array = NULL; + rchan->resize_page_count = 0; + rchan->resize_buf = NULL; + + INIT_WORK(&free_buf->work, relaybuf_free, free_buf); + schedule_delayed_work(&free_buf->work, 1); + + return 0; +} + +/** + * __relay_replace_buffer - replace channel buffer with new buffer + * @rchan: the channel + * + * Internal - see relay_replace_buffer() for details. + * + * Returns 0 if successful, negative otherwise. + */ +static int +__relay_replace_buffer(struct rchan *rchan) +{ + int oldsize; + int err = 0; + char *oldbuf; + + if (down_trylock(&rchan->resize_sem)) + return -EBUSY; + + if (rchan->init_buf) { + err = -EPERM; + goto out; + } + + if (!rchan->replace_buffer) + goto out; + + if (rchan->resizing) { + err = -EBUSY; + goto out; + } + + if (rchan->resize_buf == NULL) { + err = -EINVAL; + goto out; + } + + oldbuf = rchan->buf; + oldsize = rchan->alloc_size; + + err = do_replace_buffer(rchan, rchan->resize_alloc_size, + oldsize, rchan->n_bufs); + if (err == 0) + err = free_replaced_buffer(rchan, oldbuf, oldsize); + else + err = free_canceled_resize(rchan); +out: + rchan->replace_buffer = 0; + up(&rchan->resize_sem); + + return err; +} + +/** + * relay_replace_buffer - replace channel buffer with new buffer + * @rchan_id: the channel id + * + * Replaces the current channel buffer with the new buffer allocated + * by relay_alloc_buffer and contained in the channel struct. When the + * replacement is complete, the needs_resize() callback is called with + * RELAY_RESIZE_REPLACED. + * + * Returns 0 on success, or errcode if the channel is busy or if + * the replacement or previous allocation didn't happen for some reason. + */ +int +relay_replace_buffer(int rchan_id) +{ + int err; + + struct rchan *rchan; + + rchan = rchan_get(rchan_id); + if (rchan == NULL) + return -EBADF; + + err = __relay_replace_buffer(rchan); + + rchan_put(rchan); + + return err; +} + +EXPORT_SYMBOL(relay_realloc_buffer); +EXPORT_SYMBOL(relay_replace_buffer); + diff -urpN -X dontdiff linux-2.6.7/fs/relayfs/resize.h linux-2.6.7.relayfs/fs/relayfs/resize.h --- linux-2.6.7/fs/relayfs/resize.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/fs/relayfs/resize.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,51 @@ +#ifndef _RELAY_RESIZE_H +#define _RELAY_RESIZE_H + +/* + * If the channel usage has been below the low water mark for more than + * this amount of time, we can shrink the buffer if necessary. + */ +#define SHRINK_TIMER_SECS 60 + +/* This inspired by rtai/shmem */ +#define FIX_SIZE(x) (((x) - 1) & PAGE_MASK) + PAGE_SIZE + +/* Don't attempt resizing again after this many failures */ +#define MAX_RESIZE_FAILURES 1 + +/* Trigger resizing if a resizable channel is this full */ +#define RESIZE_THRESHOLD 3 / 4 + +/* + * Used for deferring resized channel free + */ +struct free_rchan_buf +{ + char *unmap_buf; + struct + { + struct page **array; + int count; + } page_array[3]; + + int cur; + struct work_struct work; /* resize de-allocation work struct */ +}; + +extern void * +alloc_rchan_buf(unsigned long size, + struct page ***page_array, + int *page_count); + +extern int +free_rchan_buf(void *buf, + struct page **page_array, + int page_count); + +extern void +expand_check(struct rchan *rchan); + +extern void +init_shrink_timer(struct rchan *rchan); + +#endif/* _RELAY_RESIZE_H */ diff -urpN -X dontdiff linux-2.6.7/include/asm-alpha/relay.h linux-2.6.7.relayfs/include/asm-alpha/relay.h --- linux-2.6.7/include/asm-alpha/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-alpha/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_ALPHA_RELAY_H +#define _ASM_ALPHA_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-arm/relay.h linux-2.6.7.relayfs/include/asm-arm/relay.h --- linux-2.6.7/include/asm-arm/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-arm/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_ARM_RELAY_H +#define _ASM_ARM_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-arm26/relay.h linux-2.6.7.relayfs/include/asm-arm26/relay.h --- linux-2.6.7/include/asm-arm26/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-arm26/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_ARM_RELAY_H +#define _ASM_ARM_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-cris/relay.h linux-2.6.7.relayfs/include/asm-cris/relay.h --- linux-2.6.7/include/asm-cris/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-cris/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_CRIS_RELAY_H +#define _ASM_CRIS_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-generic/relay.h linux-2.6.7.relayfs/include/asm-generic/relay.h --- linux-2.6.7/include/asm-generic/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-generic/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,76 @@ +#ifndef _ASM_GENERIC_RELAY_H +#define _ASM_GENERIC_RELAY_H +/* + * linux/include/asm-generic/relay.h + * + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * Copyright (C) 2002 - Karim Yaghmour (karim@opersys.com) + * + * Architecture-independent definitions for relayfs + */ + +#include + +/** + * get_time_delta - utility function for getting time delta + * @now: pointer to a timeval struct that may be given current time + * @rchan: the channel + * + * Returns the time difference between the current time and the buffer + * start time. + */ +static inline u32 +get_time_delta(struct timeval *now, struct rchan *rchan) +{ + u32 time_delta; + + do_gettimeofday(now); + time_delta = calc_time_delta(now, &rchan->buf_start_time); + + return time_delta; +} + +/** + * get_timestamp - utility function for getting a time and TSC pair + * @now: current time + * @tsc: the TSC associated with now + * @rchan: the channel + * + * Sets the value pointed to by now to the current time. Value pointed to + * by tsc is not set since there is no generic TSC support. + */ +static inline void +get_timestamp(struct timeval *now, + u32 *tsc, + struct rchan *rchan) +{ + do_gettimeofday(now); +} + +/** + * get_time_or_tsc: - Utility function for getting a time or a TSC. + * @now: current time + * @tsc: current TSC + * @rchan: the channel + * + * Sets the value pointed to by now to the current time. + */ +static inline void +get_time_or_tsc(struct timeval *now, + u32 *tsc, + struct rchan *rchan) +{ + do_gettimeofday(now); +} + +/** + * have_tsc - does this platform have a useable TSC? + * + * Returns 0. + */ +static inline int +have_tsc(void) +{ + return 0; +} +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-h8300/relay.h linux-2.6.7.relayfs/include/asm-h8300/relay.h --- linux-2.6.7/include/asm-h8300/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-h8300/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_H8300_RELAY_H +#define _ASM_H8300_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-i386/relay.h linux-2.6.7.relayfs/include/asm-i386/relay.h --- linux-2.6.7/include/asm-i386/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-i386/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,101 @@ +#ifndef _ASM_I386_RELAY_H +#define _ASM_I386_RELAY_H +/* + * linux/include/asm-i386/relay.h + * + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * Copyright (C) 2002 - Karim Yaghmour (karim@opersys.com) + * + * i386 definitions for relayfs + */ + +#include + +#ifdef CONFIG_X86_TSC +#include + +/** + * get_time_delta - utility function for getting time delta + * @now: pointer to a timeval struct that may be given current time + * @rchan: the channel + * + * Returns either the TSC if TSCs are being used, or the time and the + * time difference between the current time and the buffer start time + * if TSCs are not being used. + */ +static inline u32 +get_time_delta(struct timeval *now, struct rchan *rchan) +{ + u32 time_delta; + + if ((using_tsc(rchan) == 1) && cpu_has_tsc) + rdtscl(time_delta); + else { + do_gettimeofday(now); + time_delta = calc_time_delta(now, &rchan->buf_start_time); + } + + return time_delta; +} + +/** + * get_timestamp - utility function for getting a time and TSC pair + * @now: current time + * @tsc: the TSC associated with now + * @rchan: the channel + * + * Sets the value pointed to by now to the current time and the value + * pointed to by tsc to the tsc associated with that time, if the + * platform supports TSC. + */ +static inline void +get_timestamp(struct timeval *now, + u32 *tsc, + struct rchan *rchan) +{ + do_gettimeofday(now); + + if ((using_tsc(rchan) == 1) && cpu_has_tsc) + rdtscl(*tsc); +} + +/** + * get_time_or_tsc - utility function for getting a time or a TSC + * @now: current time + * @tsc: current TSC + * @rchan: the channel + * + * Sets the value pointed to by now to the current time or the value + * pointed to by tsc to the current tsc, depending on whether we're + * using TSCs or not. + */ +static inline void +get_time_or_tsc(struct timeval *now, + u32 *tsc, + struct rchan *rchan) +{ + if ((using_tsc(rchan) == 1) && cpu_has_tsc) + rdtscl(*tsc); + else + do_gettimeofday(now); +} + +/** + * have_tsc - does this platform have a useable TSC? + * + * Returns 1 if this platform has a useable TSC counter for + * timestamping purposes, 0 otherwise. + */ +static inline int +have_tsc(void) +{ + if (cpu_has_tsc) + return 1; + else + return 0; +} + +#else /* No TSC support (#ifdef CONFIG_X86_TSC) */ +#include +#endif /* #ifdef CONFIG_X86_TSC */ +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-ia64/relay.h linux-2.6.7.relayfs/include/asm-ia64/relay.h --- linux-2.6.7/include/asm-ia64/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-ia64/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_IA64_RELAY_H +#define _ASM_IA64_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-m68k/relay.h linux-2.6.7.relayfs/include/asm-m68k/relay.h --- linux-2.6.7/include/asm-m68k/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-m68k/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_M68K_RELAY_H +#define _ASM_M68K_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-m68knommu/relay.h linux-2.6.7.relayfs/include/asm-m68knommu/relay.h --- linux-2.6.7/include/asm-m68knommu/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-m68knommu/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_M68KNOMMU_RELAY_H +#define _ASM_M68KNOMMU_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-mips/relay.h linux-2.6.7.relayfs/include/asm-mips/relay.h --- linux-2.6.7/include/asm-mips/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-mips/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_RELAY_H +#define _ASM_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-mips64/relay.h linux-2.6.7.relayfs/include/asm-mips64/relay.h --- linux-2.6.7/include/asm-mips64/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-mips64/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_RELAY_H +#define _ASM_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-parisc/relay.h linux-2.6.7.relayfs/include/asm-parisc/relay.h --- linux-2.6.7/include/asm-parisc/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-parisc/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_PARISC_RELAY_H +#define _ASM_PARISC_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-ppc/relay.h linux-2.6.7.relayfs/include/asm-ppc/relay.h --- linux-2.6.7/include/asm-ppc/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-ppc/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_PPC_RELAY_H +#define _ASM_PPC_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-ppc64/relay.h linux-2.6.7.relayfs/include/asm-ppc64/relay.h --- linux-2.6.7/include/asm-ppc64/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-ppc64/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_PPC64_RELAY_H +#define _ASM_PPC64_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-s390/relay.h linux-2.6.7.relayfs/include/asm-s390/relay.h --- linux-2.6.7/include/asm-s390/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-s390/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_S390_RELAY_H +#define _ASM_S390_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-sh/relay.h linux-2.6.7.relayfs/include/asm-sh/relay.h --- linux-2.6.7/include/asm-sh/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-sh/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_SH_RELAY_H +#define _ASM_SH_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-sparc/relay.h linux-2.6.7.relayfs/include/asm-sparc/relay.h --- linux-2.6.7/include/asm-sparc/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-sparc/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_SPARC_RELAY_H +#define _ASM_SPARC_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-sparc64/relay.h linux-2.6.7.relayfs/include/asm-sparc64/relay.h --- linux-2.6.7/include/asm-sparc64/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-sparc64/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_SPARC64_RELAY_H +#define _ASM_SPARC64_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-v850/relay.h linux-2.6.7.relayfs/include/asm-v850/relay.h --- linux-2.6.7/include/asm-v850/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-v850/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef __V850_RELAY_H +#define __V850_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/asm-x86_64/relay.h linux-2.6.7.relayfs/include/asm-x86_64/relay.h --- linux-2.6.7/include/asm-x86_64/relay.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/asm-x86_64/relay.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,5 @@ +#ifndef _ASM_X86_64_RELAY_H +#define _ASM_X86_64_RELAY_H + +#include +#endif diff -urpN -X dontdiff linux-2.6.7/include/linux/klog.h linux-2.6.7.relayfs/include/linux/klog.h --- linux-2.6.7/include/linux/klog.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/linux/klog.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,24 @@ +/* + * KLOG Generic Logging facility built upon the relayfs infrastructure + * + * Authors: Hubertus Frankeh (frankeh@us.ibm.com) + * Tom Zanussi (zanussi@us.ibm.com) + * + * Please direct all questions/comments to zanussi@us.ibm.com + * + * Copyright (C) 2003, IBM Corp + * + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + */ + +#ifndef _LINUX_KLOG_H +#define _LINUX_KLOG_H + +extern int klog(const char *fmt, ...); +extern int klog_raw(const char *buf,int len); + +#endif /* _LINUX_KLOG_H */ diff -urpN -X dontdiff linux-2.6.7/include/linux/relayfs_fs.h linux-2.6.7.relayfs/include/linux/relayfs_fs.h --- linux-2.6.7/include/linux/relayfs_fs.h 1969-12-31 18:00:00.000000000 -0600 +++ linux-2.6.7.relayfs/include/linux/relayfs_fs.h 2004-06-24 00:52:59.000000000 -0500 @@ -0,0 +1,687 @@ +/* + * linux/include/linux/relayfs_fs.h + * + * Copyright (C) 2002, 2003 - Tom Zanussi (zanussi@us.ibm.com), IBM Corp + * Copyright (C) 1999, 2000, 2001, 2002 - Karim Yaghmour (karim@opersys.com) + * + * RelayFS definitions and declarations + * + * Please see Documentation/filesystems/relayfs.txt for more info. + */ + +#ifndef _LINUX_RELAYFS_FS_H +#define _LINUX_RELAYFS_FS_H + +#include +#include +#include +#include +#include +#include + +/* + * Tracks changes to rchan struct + */ +#define RELAYFS_CHANNEL_VERSION 1 + +/* + * Maximum number of simultaneously open channels + */ +#define RELAY_MAX_CHANNELS 256 + +/* + * Relay properties + */ +#define RELAY_MIN_BUFS 2 +#define RELAY_MIN_BUFSIZE 4096 +#define RELAY_MAX_BUFS 256 +#define RELAY_MAX_BUF_SIZE 0x1000000 +#define RELAY_MAX_TOTAL_BUF_SIZE 0x8000000 + +/* + * Lockless scheme utility macros + */ +#define RELAY_MAX_BUFNO(bufno_bits) (1UL << (bufno_bits)) +#define RELAY_BUF_SIZE(offset_bits) (1UL << (offset_bits)) +#define RELAY_BUF_OFFSET_MASK(offset_bits) (RELAY_BUF_SIZE(offset_bits) - 1) +#define RELAY_BUFNO_GET(index, offset_bits) ((index) >> (offset_bits)) +#define RELAY_BUF_OFFSET_GET(index, mask) ((index) & (mask)) +#define RELAY_BUF_OFFSET_CLEAR(index, mask) ((index) & ~(mask)) + +/* + * Flags returned by relay_reserve() + */ +#define RELAY_BUFFER_SWITCH_NONE 0x0 +#define RELAY_WRITE_DISCARD_NONE 0x0 +#define RELAY_BUFFER_SWITCH 0x1 +#define RELAY_WRITE_DISCARD 0x2 +#define RELAY_WRITE_TOO_LONG 0x4 + +/* + * Relay attribute flags + */ +#define RELAY_DELIVERY_BULK 0x1 +#define RELAY_DELIVERY_PACKET 0x2 +#define RELAY_SCHEME_LOCKLESS 0x4 +#define RELAY_SCHEME_LOCKING 0x8 +#define RELAY_SCHEME_ANY 0xC +#define RELAY_TIMESTAMP_TSC 0x10 +#define RELAY_TIMESTAMP_GETTIMEOFDAY 0x20 +#define RELAY_TIMESTAMP_ANY 0x30 +#define RELAY_USAGE_SMP 0x40 +#define RELAY_USAGE_GLOBAL 0x80 +#define RELAY_MODE_CONTINUOUS 0x100 +#define RELAY_MODE_NO_OVERWRITE 0x200 + +/* + * Flags for needs_resize() callback + */ +#define RELAY_RESIZE_NONE 0x0 +#define RELAY_RESIZE_EXPAND 0x1 +#define RELAY_RESIZE_SHRINK 0x2 +#define RELAY_RESIZE_REPLACE 0x4 +#define RELAY_RESIZE_REPLACED 0x8 + +/* + * Values for fileop_notify() callback + */ +enum relay_fileop +{ + RELAY_FILE_OPEN, + RELAY_FILE_CLOSE, + RELAY_FILE_MAP, + RELAY_FILE_UNMAP +}; + +/* + * Data structure returned by relay_info() + */ +struct rchan_info +{ + u32 flags; /* relay attribute flags for channel */ + u32 buf_size; /* channel's sub-buffer size */ + char *buf_addr; /* address of channel start */ + u32 alloc_size; /* total buffer size actually allocated */ + u32 n_bufs; /* number of sub-buffers in channel */ + u32 cur_idx; /* current write index into channel */ + u32 bufs_produced; /* current count of sub-buffers produced */ + u32 bufs_consumed; /* current count of sub-buffers consumed */ + u32 buf_id; /* buf_id of current sub-buffer */ + int buffer_complete[RELAY_MAX_BUFS]; /* boolean per sub-buffer */ + int unused_bytes[RELAY_MAX_BUFS]; /* count per sub-buffer */ +}; + +/* + * Relay channel client callbacks + */ +struct rchan_callbacks +{ + /* + * buffer_start - called at the beginning of a new sub-buffer + * @rchan_id: the channel id + * @current_write_pos: position in sub-buffer client should write to + * @buffer_id: the id of the new sub-buffer + * @start_time: the timestamp associated with the start of sub-buffer + * @start_tsc: the TSC associated with the timestamp, if using_tsc + * @using_tsc: boolean, indicates whether start_tsc is valid + * + * Return value should be the number of bytes written by the client. + * + * See Documentation/filesystems/relayfs.txt for details. + */ + int (*buffer_start) (int rchan_id, + char *current_write_pos, + u32 buffer_id, + struct timeval start_time, + u32 start_tsc, + int using_tsc); + + /* + * buffer_end - called at the end of a sub-buffer + * @rchan_id: the channel id + * @current_write_pos: position in sub-buffer of end of data + * @end_of_buffer: the position of the end of the sub-buffer + * @end_time: the timestamp associated with the end of the sub-buffer + * @end_tsc: the TSC associated with the end_time, if using_tsc + * @using_tsc: boolean, indicates whether end_tsc is valid + * + * Return value should be the number of bytes written by the client. + * + * See Documentation/filesystems/relayfs.txt for details. + */ + int (*buffer_end) (int rchan_id, + char *current_write_pos, + char *end_of_buffer, + struct timeval end_time, + u32 end_tsc, + int using_tsc); + + /* + * deliver - called when data is ready for the client + * @rchan_id: the channel id + * @from: the start of the delivered data + * @len: the length of the delivered data + * + * See Documentation/filesystems/relayfs.txt for details. + */ + void (*deliver) (int rchan_id, char *from, u32 len); + + /* + * user_deliver - called when data has been written from userspace + * @rchan_id: the channel id + * @from: the start of the delivered data + * @len: the length of the delivered data + * + * See Documentation/filesystems/relayfs.txt for details. + */ + void (*user_deliver) (int rchan_id, char *from, u32 len); + + /* + * needs_resize - called when a resizing event occurs + * @rchan_id: the channel id + * @resize_type: the type of resizing event + * @suggested_buf_size: the suggested new sub-buffer size + * @suggested_buf_size: the suggested new number of sub-buffers + * + * See Documentation/filesystems/relayfs.txt for details. + */ + void (*needs_resize)(int rchan_id, + int resize_type, + u32 suggested_buf_size, + u32 suggested_n_bufs); + + /* + * fileop_notify - called on open/close/mmap/munmap of a relayfs file + * @rchan_id: the channel id + * @filp: relayfs file pointer + * @fileop: which file operation is in progress + * + * The return value can direct the outcome of the operation. + * + * See Documentation/filesystems/relayfs.txt for details. + */ + int (*fileop_notify)(int rchan_id, + struct file *filp, + enum relay_fileop fileop); + + /* + * ioctl - called in ioctl context from userspace + * @rchan_id: the channel id + * @cmd: ioctl cmd + * @arg: ioctl cmd arg + * + * The return value is returned as the value from the ioctl call. + * + * See Documentation/filesystems/relayfs.txt for details. + */ + int (*ioctl) (int rchan_id, unsigned int cmd, unsigned long arg); +}; + +/* + * Lockless scheme-specific data + */ +struct lockless_rchan +{ + u8 bufno_bits; /* # bits used for sub-buffer id */ + u8 offset_bits; /* # bits used for offset within sub-buffer */ + u32 index; /* current index = sub-buffer id and offset */ + u32 offset_mask; /* used to obtain offset portion of index */ + u32 index_mask; /* used to mask off unused bits index */ + atomic_t fill_count[RELAY_MAX_BUFS]; /* fill count per sub-buffer */ +}; + +/* + * Locking scheme-specific data + */ +struct locking_rchan +{ + char *write_buf; /* start of write sub-buffer */ + char *write_buf_end; /* end of write sub-buffer */ + char *current_write_pos; /* current write pointer */ + char *write_limit; /* takes reserves into account */ + char *in_progress_event_pos; /* used for interrupted writes */ + u16 in_progress_event_size; /* used for interrupted writes */ + char *interrupted_pos; /* used for interrupted writes */ + u16 interrupting_size; /* used for interrupted writes */ + spinlock_t lock; /* channel lock for locking scheme */ +}; + +struct relay_ops; + +/* + * Offset resizing data structure + */ +struct resize_offset +{ + u32 ge; + u32 le; + int delta; +}; + +/* + * Relay channel data structure + */ +struct rchan +{ + u32 version; /* the version of this struct */ + char *buf; /* the channel buffer */ + union + { + struct lockless_rchan lockless; + struct locking_rchan locking; + } scheme; /* scheme-specific channel data */ + + int id; /* the channel id */ + struct rchan_callbacks *callbacks; /* client callbacks */ + u32 flags; /* relay channel attributes */ + u32 buf_id; /* current sub-buffer id */ + u32 buf_idx; /* current sub-buffer index */ + + atomic_t mapped; /* map count */ + + atomic_t suspended; /* channel suspended i.e full? */ + int half_switch; /* used internally for suspend */ + + struct timeval buf_start_time; /* current sub-buffer start time */ + u32 buf_start_tsc; /* current sub-buffer start TSC */ + + u32 buf_size; /* sub-buffer size */ + u32 alloc_size; /* total buffer size allocated */ + u32 n_bufs; /* number of sub-buffers */ + + u32 bufs_produced; /* count of sub-buffers produced */ + u32 bufs_consumed; /* count of sub-buffers consumed */ + u32 bytes_consumed; /* bytes consumed in cur sub-buffer */ + u32 read_start; /* start VFS readers here */ + + int initialized; /* first buffer initialized? */ + int finalized; /* channel finalized? */ + + u32 start_reserve; /* reserve at start of sub-buffers */ + u32 end_reserve; /* reserve at end of sub-buffers */ + u32 rchan_start_reserve; /* additional reserve sub-buffer 0 */ + + struct dentry *dentry; /* channel file dentry */ + + wait_queue_head_t read_wait; /* VFS read wait queue */ + wait_queue_head_t write_wait; /* VFS write wait queue */ + struct work_struct wake_readers; /* reader wake-up work struct */ + struct work_struct wake_writers; /* reader wake-up work struct */ + atomic_t refcount; /* channel refcount */ + + struct relay_ops *relay_ops; /* scheme-specific channel ops */ + + int unused_bytes[RELAY_MAX_BUFS]; /* unused count per sub-buffer */ + + struct semaphore resize_sem; /* serializes alloc/repace */ + struct work_struct work; /* resize allocation work struct */ + + struct list_head open_readers; /* open readers for this channel */ + rwlock_t open_readers_lock; /* protection for open_readers list */ + + char *init_buf; /* init channel buffer, if non-NULL */ + + u32 resize_min; /* minimum resized total buffer size */ + u32 resize_max; /* maximum resized total buffer size */ + char *resize_buf; /* for autosize alloc/free */ + u32 resize_buf_size; /* resized sub-buffer size */ + u32 resize_n_bufs; /* resized number of sub-buffers */ + u32 resize_alloc_size; /* resized actual total size */ + int resizing; /* is resizing in progress? */ + int resize_err; /* resizing err code */ + int resize_failures; /* number of resize failures */ + int replace_buffer; /* is the alloced buffer ready? */ + struct resize_offset resize_offset; /* offset change */ + struct timer_list shrink_timer; /* timer used for shrinking */ + int resize_order; /* size of last resize */ + u32 expand_buf_id; /* subbuf id expand will occur at */ + + struct page **buf_page_array; /* array of current buffer pages */ + int buf_page_count; /* number of current buffer pages */ + struct page **expand_page_array;/* new pages to be inserted */ + int expand_page_count; /* number of new pages */ + struct page **shrink_page_array;/* old pages to be freed */ + int shrink_page_count; /* number of old pages */ + struct page **resize_page_array;/* will become current pages */ + int resize_page_count; /* number of resize pages */ + struct page **old_buf_page_array; /* hold for freeing */ +} ____cacheline_aligned; + +/* + * Relay channel reader struct + */ +struct rchan_reader +{ + struct list_head list; /* for list inclusion */ + struct rchan *rchan; /* the channel we're reading from */ + int auto_consume; /* does this reader auto-consume? */ + u32 bufs_consumed; /* buffers this reader has consumed */ + u32 bytes_consumed; /* bytes consumed in cur sub-buffer */ + int offset_changed; /* have channel offsets changed? */ + int vfs_reader; /* are we a VFS reader? */ + int map_reader; /* are we an mmap reader? */ + + union + { + struct file *file; + u32 f_pos; + } pos; /* current read offset */ +}; + +/* + * These help make union member access less tedious + */ +#define channel_buffer(rchan) ((rchan)->buf) +#define idx(rchan) ((rchan)->scheme.lockless.index) +#define bufno_bits(rchan) ((rchan)->scheme.lockless.bufno_bits) +#define offset_bits(rchan) ((rchan)->scheme.lockless.offset_bits) +#define offset_mask(rchan) ((rchan)->scheme.lockless.offset_mask) +#define idx_mask(rchan) ((rchan)->scheme.lockless.index_mask) +#define bulk_delivery(rchan) (((rchan)->flags & RELAY_DELIVERY_BULK) ? 1 : 0) +#define packet_delivery(rchan) (((rchan)->flags & RELAY_DELIVERY_PACKET) ? 1 : 0) +#define using_lockless(rchan) (((rchan)->flags & RELAY_SCHEME_LOCKLESS) ? 1 : 0) +#define using_locking(rchan) (((rchan)->flags & RELAY_SCHEME_LOCKING) ? 1 : 0) +#define using_tsc(rchan) (((rchan)->flags & RELAY_TIMESTAMP_TSC) ? 1 : 0) +#define using_gettimeofday(rchan) (((rchan)->flags & RELAY_TIMESTAMP_GETTIMEOFDAY) ? 1 : 0) +#define usage_smp(rchan) (((rchan)->flags & RELAY_USAGE_SMP) ? 1 : 0) +#define usage_global(rchan) (((rchan)->flags & RELAY_USAGE_GLOBAL) ? 1 : 0) +#define mode_continuous(rchan) (((rchan)->flags & RELAY_MODE_CONTINUOUS) ? 1 : 0) +#define fill_count(rchan, i) ((rchan)->scheme.lockless.fill_count[(i)]) +#define write_buf(rchan) ((rchan)->scheme.locking.write_buf) +#define read_buf(rchan) ((rchan)->scheme.locking.read_buf) +#define write_buf_end(rchan) ((rchan)->scheme.locking.write_buf_end) +#define read_buf_end(rchan) ((rchan)->scheme.locking.read_buf_end) +#define cur_write_pos(rchan) ((rchan)->scheme.locking.current_write_pos) +#define read_limit(rchan) ((rchan)->scheme.locking.read_limit) +#define write_limit(rchan) ((rchan)->scheme.locking.write_limit) +#define in_progress_event_pos(rchan) ((rchan)->scheme.locking.in_progress_event_pos) +#define in_progress_event_size(rchan) ((rchan)->scheme.locking.in_progress_event_size) +#define interrupted_pos(rchan) ((rchan)->scheme.locking.interrupted_pos) +#define interrupting_size(rchan) ((rchan)->scheme.locking.interrupting_size) +#define channel_lock(rchan) ((rchan)->scheme.locking.lock) + + +/** + * calc_time_delta - utility function for time delta calculation + * @now: current time + * @start: start time + * + * Returns the time delta produced by subtracting start time from now. + */ +static inline u32 +calc_time_delta(struct timeval *now, + struct timeval *start) +{ + return (now->tv_sec - start->tv_sec) * 1000000 + + (now->tv_usec - start->tv_usec); +} + +/** + * recalc_time_delta - utility function for time delta recalculation + * @now: current time + * @new_delta: the new time delta calculated + * @cpu: the associated CPU id + */ +static inline void +recalc_time_delta(struct timeval *now, + u32 *new_delta, + struct rchan *rchan) +{ + if (using_tsc(rchan) == 0) + *new_delta = calc_time_delta(now, &rchan->buf_start_time); +} + +/** + * have_cmpxchg - does this architecture have a cmpxchg? + * + * Returns 1 if this architecture has a cmpxchg useable by + * the lockless scheme, 0 otherwise. + */ +static inline int +have_cmpxchg(void) +{ +#if defined(__HAVE_ARCH_CMPXCHG) + return 1; +#else + return 0; +#endif +} + +/** + * relay_write_direct - write data directly into destination buffer + */ +#define relay_write_direct(DEST, SRC, SIZE) \ +do\ +{\ + memcpy(DEST, SRC, SIZE);\ + DEST += SIZE;\ +} while (0); + +/** + * relay_lock_channel - lock the relay channel if applicable + * + * This macro only affects the locking scheme. If the locking scheme + * is in use and the channel usage is SMP, does a local_irq_save. If the + * locking sheme is in use and the channel usage is GLOBAL, uses + * spin_lock_irqsave. FLAGS is initialized to 0 since we know that + * it is being initialized prior to use and we avoid the compiler warning. + */ +#define relay_lock_channel(RCHAN, FLAGS) \ +do\ +{\ + FLAGS = 0;\ + if (using_locking(RCHAN)) {\ + if (usage_smp(RCHAN)) {\ + local_irq_save(FLAGS); \ + } else {\ + spin_lock_irqsave(&(RCHAN)->scheme.locking.lock, FLAGS); \ + }\ + }\ +} while (0); + +/** + * relay_unlock_channel - unlock the relay channel if applicable + * + * This macro only affects the locking scheme. See relay_lock_channel. + */ +#define relay_unlock_channel(RCHAN, FLAGS) \ +do\ +{\ + if (using_locking(RCHAN)) {\ + if (usage_smp(RCHAN)) {\ + local_irq_restore(FLAGS); \ + } else {\ + spin_unlock_irqrestore(&(RCHAN)->scheme.locking.lock, FLAGS); \ + }\ + }\ +} while (0); + +/* + * Define cmpxchg if we don't have it + */ +#ifndef __HAVE_ARCH_CMPXCHG +#define cmpxchg(p,o,n) 0 +#endif + +/* + * High-level relayfs kernel API, fs/relayfs/relay.c + */ +extern int +relay_open(const char *chanpath, + int bufsize, + int nbufs, + u32 flags, + struct rchan_callbacks *channel_callbacks, + u32 start_reserve, + u32 end_reserve, + u32 rchan_start_reserve, + u32 resize_min, + u32 resize_max, + int mode, + char *init_buf, + u32 init_buf_size); + +extern int +relay_close(int rchan_id); + +extern int +relay_write(int rchan_id, + const void *data_ptr, + size_t count, + int td_offset, + void **wrote_pos); + +extern ssize_t +relay_read(struct rchan_reader *reader, + char *buf, + size_t count, + int wait, + u32 *actual_read_offset); + +extern int +relay_discard_init_buf(int rchan_id); + +extern struct rchan_reader * +add_rchan_reader(int rchan_id, int autoconsume); + +extern int +remove_rchan_reader(struct rchan_reader *reader); + +extern struct rchan_reader * +add_map_reader(int rchan_id); + +extern int +remove_map_reader(struct rchan_reader *reader); + +extern int +relay_info(int rchan_id, struct rchan_info *rchan_info); + +extern void +relay_buffers_consumed(struct rchan_reader *reader, u32 buffers_consumed); + +extern void +relay_bytes_consumed(struct rchan_reader *reader, u32 bytes_consumed, u32 read_offset); + +extern ssize_t +relay_bytes_avail(struct rchan_reader *reader); + +extern int +relay_realloc_buffer(int rchan_id, u32 new_nbufs, int in_background); + +extern int +relay_replace_buffer(int rchan_id); + +extern int +rchan_empty(struct rchan_reader *reader); + +extern int +rchan_full(struct rchan_reader *reader); + +extern void +update_readers_consumed(struct rchan *rchan, u32 bufs_consumed, u32 bytes_consumed); + +extern int +__relay_mmap_buffer(struct rchan *rchan, struct vm_area_struct *vma); + +extern struct rchan_reader * +__add_rchan_reader(struct rchan *rchan, struct file *filp, int auto_consume, int map_reader); + +extern void +__remove_rchan_reader(struct rchan_reader *reader); + +/* + * Low-level relayfs kernel API, fs/relayfs/relay.c + */ +extern struct rchan * +rchan_get(int rchan_id); + +extern void +rchan_put(struct rchan *rchan); + +extern char * +relay_reserve(struct rchan *rchan, + u32 data_len, + struct timeval *time_stamp, + u32 *time_delta, + int *errcode, + int *interrupting); + +extern void +relay_commit(struct rchan *rchan, + char *from, + u32 len, + int reserve_code, + int interrupting); + +extern u32 +relay_get_offset(struct rchan *rchan, u32 *max_offset); + +extern int +relay_reset(int rchan_id); + +/* + * VFS functions, fs/relayfs/inode.c + */ +extern int +relayfs_create_dir(const char *name, + struct dentry *parent, + struct dentry **dentry); + +extern int +relayfs_create_file(const char * name, + struct dentry *parent, + struct dentry **dentry, + void * data, + int mode); + +extern int +relayfs_remove_file(struct dentry *dentry); + +extern int +reset_index(struct rchan *rchan, u32 old_index); + + +/* + * klog functions, fs/relayfs/klog.c + */ +extern int +create_klog_channel(void); + +extern int +remove_klog_channel(void); + +/* + * Scheme-specific channel ops + */ +struct relay_ops +{ + char * (*reserve) (struct rchan *rchan, + u32 slot_len, + struct timeval *time_stamp, + u32 *tsc, + int * errcode, + int * interrupting); + + void (*commit) (struct rchan *rchan, + char *from, + u32 len, + int deliver, + int interrupting); + + u32 (*get_offset) (struct rchan *rchan, + u32 *max_offset); + + void (*resume) (struct rchan *rchan); + void (*finalize) (struct rchan *rchan); + void (*reset) (struct rchan *rchan, + int init); + int (*reset_index) (struct rchan *rchan, + u32 old_index); +}; + +#endif /* _LINUX_RELAYFS_FS_H */ + + + + +