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/*
* linux/fs/nfs/nfsiod.c
*
* Async NFS RPC call support.
*
* When a process wants to place an asynchronous RPC call, it reserves
* an nfsiod slot, fills in all necessary fields including the callback
* handler field, and enqueues the request.
*
* This will wake up nfsiod, which calls nfs_rpc_doio to collect the
* reply. It then dispatches the result to the caller via the callback
* function, including result value and request pointer. It then re-inserts
* itself into the free list.
*
* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/sched.h>
#include <linux/nfs_fs.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/rpcsock.h>
#include <linux/nfsiod.h>
static struct nfsiod_req * free_list = NULL;
static int active = 0;
#undef DEBUG_NFSIOD
#ifdef DEBUG_NFSIOD
#define dprintk(args...) printk(## args)
#else
#define dprintk(args...) /* nothing */
#endif
/*
* Reserve an nfsiod slot and initialize the request struct
*/
struct nfsiod_req *
nfsiod_reserve(struct nfs_server *server)
{
struct nfsiod_req *req;
if (!(req = free_list)) {
dprintk("BIO: nfsiod_reserve: no free nfsiods\n");
return NULL;
}
free_list = req->rq_next;
memset(&req->rq_rpcreq, 0, sizeof(struct rpc_ioreq));
if (rpc_reserve(server->rsock, &req->rq_rpcreq, 1) < 0) {
dprintk("BIO: nfsiod_reserve failed to reserve RPC slot\n");
req->rq_next = free_list;
free_list = req;
return NULL;
}
req->rq_server = server;
return req;
}
void
nfsiod_release(struct nfsiod_req *req)
{
dprintk("BIO: nfsiod_release called\n");
rpc_release(req->rq_server->rsock, &req->rq_rpcreq);
memset(&req->rq_rpcreq, 0, sizeof(struct rpc_ioreq));
req->rq_next = free_list;
free_list = req;
}
/*
* Transmit a request and put it on nfsiod's list of pending requests.
*/
void
nfsiod_enqueue(struct nfsiod_req *req)
{
dprintk("BIO: enqueuing request %p\n", &req->rq_rpcreq);
wake_up(&req->rq_wait);
schedule();
}
/*
* This is the main nfsiod loop.
*/
int
nfsiod(void)
{
struct nfsiod_req request, *req = &request;
int result;
dprintk("BIO: nfsiod %d starting\n", current->pid);
while (1) {
/* Insert request into free list */
memset(req, 0, sizeof(*req));
req->rq_next = free_list;
free_list = req;
/* Wait until user enqueues request */
dprintk("BIO: before: now %d nfsiod's active\n", active);
dprintk("BIO: nfsiod %d waiting\n", current->pid);
interruptible_sleep_on(&req->rq_wait);
if (current->signal & ~current->blocked)
break;
if (!req->rq_rpcreq.rq_slot)
continue;
dprintk("BIO: nfsiod %d woken up; calling nfs_rpc_doio.\n",
current->pid);
active++;
dprintk("BIO: before: now %d nfsiod's active\n", active);
do {
result = nfs_rpc_doio(req->rq_server,
&req->rq_rpcreq, 1);
} while (!req->rq_callback(result, req));
active--;
}
return 0;
}
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