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/*
* Copyright (c) 2011-2015 Intel Corporation. All rights reserved.
*
* This software is available to you under a choice of one of two
* licenses. You may choose to be licensed under the terms of the GNU
* General Public License (GPL) Version 2, available from the file
* COPYING in the main directory of this source tree, or the
* BSD license below:
*
* Redistribution and use in source and binary forms, with or
* without modification, are permitted provided that the following
* conditions are met:
*
* - Redistributions of source code must retain the above
* copyright notice, this list of conditions and the following
* disclaimer.
*
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#ifndef _OFI_SIGNAL_H_
#define _OFI_SIGNAL_H_
#include "config.h"
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <ofi_file.h>
#include <ofi_osd.h>
#include <ofi_atom.h>
#include <rdma/fi_errno.h>
enum {
FI_READ_FD,
FI_WRITE_FD
};
struct fd_signal {
ofi_mutex_t lock;
int fd[2];
int byte_avail;
};
static inline int fd_signal_init(struct fd_signal *signal)
{
int ret;
ret = socketpair(AF_UNIX, SOCK_STREAM, 0, signal->fd);
if (ret < 0)
return -ofi_sockerr();
signal->byte_avail = 0;
ret = ofi_mutex_init(&signal->lock);
if (ret)
goto err1;
/* The read fd is accessed directly by fd_signal users to add
* it to epoll fd's and wait sets.
*/
ret = fi_fd_nonblock(signal->fd[FI_READ_FD]);
if (ret)
goto err2;
return 0;
err2:
ofi_mutex_destroy(&signal->lock);
err1:
ofi_close_socket(signal->fd[0]);
ofi_close_socket(signal->fd[1]);
return ret;
}
static inline void fd_signal_free(struct fd_signal *signal)
{
ofi_close_socket(signal->fd[0]);
ofi_close_socket(signal->fd[1]);
ofi_mutex_destroy(&signal->lock);
}
static inline void fd_signal_set(struct fd_signal *signal)
{
char c = 0;
int ret;
ofi_mutex_lock(&signal->lock);
if (!signal->byte_avail) {
ret = ofi_write_socket(signal->fd[FI_WRITE_FD], &c, sizeof c);
assert(ret == sizeof c);
if (ret == sizeof c)
signal->byte_avail++;
}
ofi_mutex_unlock(&signal->lock);
}
static inline int fd_signal_poll(struct fd_signal *signal, int timeout)
{
int ret;
ret = fi_poll_fd(signal->fd[FI_READ_FD], timeout);
if (ret < 0)
return ret;
return (ret == 0) ? -FI_ETIMEDOUT : 0;
}
/* There's a race where we can write data to the fd and increment byte_avail,
* but the kernel won't have the data available for reading from the fd yet.
* If the data isn't ready for reading, but has already been written, we'll
* wait for it to show up. A timeout is given just so that we don't end up
* blocking forever in case something goes terribly astray.
*/
static inline void fd_signal_reset(struct fd_signal *signal)
{
char c;
int ret;
ofi_mutex_lock(&signal->lock);
while (signal->byte_avail) {
ret = ofi_read_socket(signal->fd[FI_READ_FD], &c, sizeof c);
if (ret == sizeof c) {
signal->byte_avail--;
continue;
}
if (!OFI_SOCK_TRY_SND_RCV_AGAIN(ofi_sockerr())) {
assert(0);
break;
}
/* Give the kernel up to 10 seconds to get the data there. */
ret = fd_signal_poll(signal, 10000);
if (ret) {
assert(0);
break;
}
}
ofi_mutex_unlock(&signal->lock);
}
static inline int fd_signal_get(struct fd_signal *signal)
{
return signal->fd[FI_READ_FD];
}
#endif /* _OFI_SIGNAL_H_ */
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