2 * linux/net/sunrpc/xprt.c
4 * This is a generic RPC call interface supporting congestion avoidance,
5 * and asynchronous calls.
7 * The interface works like this:
9 * - When a process places a call, it allocates a request slot if
10 * one is available. Otherwise, it sleeps on the backlog queue
12 * - Next, the caller puts together the RPC message, stuffs it into
13 * the request struct, and calls xprt_transmit().
14 * - xprt_transmit sends the message and installs the caller on the
15 * transport's wait list. At the same time, it installs a timer that
16 * is run after the packet's timeout has expired.
17 * - When a packet arrives, the data_ready handler walks the list of
18 * pending requests for that transport. If a matching XID is found, the
19 * caller is woken up, and the timer removed.
20 * - When no reply arrives within the timeout interval, the timer is
21 * fired by the kernel and runs xprt_timer(). It either adjusts the
22 * timeout values (minor timeout) or wakes up the caller with a status
24 * - When the caller receives a notification from RPC that a reply arrived,
25 * it should release the RPC slot, and process the reply.
26 * If the call timed out, it may choose to retry the operation by
27 * adjusting the initial timeout value, and simply calling rpc_call
30 * Support for async RPC is done through a set of RPC-specific scheduling
31 * primitives that `transparently' work for processes as well as async
32 * tasks that rely on callbacks.
34 * Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de>
36 * Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com>
39 #include <linux/module.h>
41 #include <linux/types.h>
42 #include <linux/interrupt.h>
43 #include <linux/workqueue.h>
44 #include <linux/net.h>
46 #include <linux/sunrpc/clnt.h>
47 #include <linux/sunrpc/metrics.h>
54 # define RPCDBG_FACILITY RPCDBG_XPRT
60 static void xprt_request_init(struct rpc_task *, struct rpc_xprt *);
61 static inline void do_xprt_reserve(struct rpc_task *);
62 static void xprt_connect_status(struct rpc_task *task);
63 static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
66 * The transport code maintains an estimate on the maximum number of out-
67 * standing RPC requests, using a smoothed version of the congestion
68 * avoidance implemented in 44BSD. This is basically the Van Jacobson
69 * congestion algorithm: If a retransmit occurs, the congestion window is
70 * halved; otherwise, it is incremented by 1/cwnd when
72 * - a reply is received and
73 * - a full number of requests are outstanding and
74 * - the congestion window hasn't been updated recently.
76 #define RPC_CWNDSHIFT (8U)
77 #define RPC_CWNDSCALE (1U << RPC_CWNDSHIFT)
78 #define RPC_INITCWND RPC_CWNDSCALE
79 #define RPC_MAXCWND(xprt) ((xprt)->max_reqs << RPC_CWNDSHIFT)
81 #define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
84 * xprt_reserve_xprt - serialize write access to transports
85 * @task: task that is requesting access to the transport
87 * This prevents mixing the payload of separate requests, and prevents
88 * transport connects from colliding with writes. No congestion control
91 int xprt_reserve_xprt(struct rpc_task *task)
93 struct rpc_xprt *xprt = task->tk_xprt;
94 struct rpc_rqst *req = task->tk_rqstp;
96 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
97 if (task == xprt->snd_task)
103 xprt->snd_task = task;
105 req->rq_bytes_sent = 0;
111 dprintk("RPC: %4d failed to lock transport %p\n",
113 task->tk_timeout = 0;
114 task->tk_status = -EAGAIN;
115 if (req && req->rq_ntrans)
116 rpc_sleep_on(&xprt->resend, task, NULL, NULL);
118 rpc_sleep_on(&xprt->sending, task, NULL, NULL);
122 static void xprt_clear_locked(struct rpc_xprt *xprt)
124 xprt->snd_task = NULL;
125 if (!test_bit(XPRT_CLOSE_WAIT, &xprt->state) || xprt->shutdown) {
126 smp_mb__before_clear_bit();
127 clear_bit(XPRT_LOCKED, &xprt->state);
128 smp_mb__after_clear_bit();
130 schedule_work(&xprt->task_cleanup);
134 * xprt_reserve_xprt_cong - serialize write access to transports
135 * @task: task that is requesting access to the transport
137 * Same as xprt_reserve_xprt, but Van Jacobson congestion control is
138 * integrated into the decision of whether a request is allowed to be
139 * woken up and given access to the transport.
141 int xprt_reserve_xprt_cong(struct rpc_task *task)
143 struct rpc_xprt *xprt = task->tk_xprt;
144 struct rpc_rqst *req = task->tk_rqstp;
146 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
147 if (task == xprt->snd_task)
151 if (__xprt_get_cong(xprt, task)) {
152 xprt->snd_task = task;
154 req->rq_bytes_sent = 0;
159 xprt_clear_locked(xprt);
161 dprintk("RPC: %4d failed to lock transport %p\n", task->tk_pid, xprt);
162 task->tk_timeout = 0;
163 task->tk_status = -EAGAIN;
164 if (req && req->rq_ntrans)
165 rpc_sleep_on(&xprt->resend, task, NULL, NULL);
167 rpc_sleep_on(&xprt->sending, task, NULL, NULL);
171 static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
175 spin_lock_bh(&xprt->transport_lock);
176 retval = xprt->ops->reserve_xprt(task);
177 spin_unlock_bh(&xprt->transport_lock);
181 static void __xprt_lock_write_next(struct rpc_xprt *xprt)
183 struct rpc_task *task;
184 struct rpc_rqst *req;
186 if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
189 task = rpc_wake_up_next(&xprt->resend);
191 task = rpc_wake_up_next(&xprt->sending);
196 req = task->tk_rqstp;
197 xprt->snd_task = task;
199 req->rq_bytes_sent = 0;
205 xprt_clear_locked(xprt);
208 static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
210 struct rpc_task *task;
212 if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
214 if (RPCXPRT_CONGESTED(xprt))
216 task = rpc_wake_up_next(&xprt->resend);
218 task = rpc_wake_up_next(&xprt->sending);
222 if (__xprt_get_cong(xprt, task)) {
223 struct rpc_rqst *req = task->tk_rqstp;
224 xprt->snd_task = task;
226 req->rq_bytes_sent = 0;
232 xprt_clear_locked(xprt);
236 * xprt_release_xprt - allow other requests to use a transport
237 * @xprt: transport with other tasks potentially waiting
238 * @task: task that is releasing access to the transport
240 * Note that "task" can be NULL. No congestion control is provided.
242 void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
244 if (xprt->snd_task == task) {
245 xprt_clear_locked(xprt);
246 __xprt_lock_write_next(xprt);
251 * xprt_release_xprt_cong - allow other requests to use a transport
252 * @xprt: transport with other tasks potentially waiting
253 * @task: task that is releasing access to the transport
255 * Note that "task" can be NULL. Another task is awoken to use the
256 * transport if the transport's congestion window allows it.
258 void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
260 if (xprt->snd_task == task) {
261 xprt_clear_locked(xprt);
262 __xprt_lock_write_next_cong(xprt);
266 static inline void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
268 spin_lock_bh(&xprt->transport_lock);
269 xprt->ops->release_xprt(xprt, task);
270 spin_unlock_bh(&xprt->transport_lock);
274 * Van Jacobson congestion avoidance. Check if the congestion window
275 * overflowed. Put the task to sleep if this is the case.
278 __xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task)
280 struct rpc_rqst *req = task->tk_rqstp;
284 dprintk("RPC: %4d xprt_cwnd_limited cong = %ld cwnd = %ld\n",
285 task->tk_pid, xprt->cong, xprt->cwnd);
286 if (RPCXPRT_CONGESTED(xprt))
289 xprt->cong += RPC_CWNDSCALE;
294 * Adjust the congestion window, and wake up the next task
295 * that has been sleeping due to congestion
298 __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
303 xprt->cong -= RPC_CWNDSCALE;
304 __xprt_lock_write_next_cong(xprt);
308 * xprt_release_rqst_cong - housekeeping when request is complete
309 * @task: RPC request that recently completed
311 * Useful for transports that require congestion control.
313 void xprt_release_rqst_cong(struct rpc_task *task)
315 __xprt_put_cong(task->tk_xprt, task->tk_rqstp);
319 * xprt_adjust_cwnd - adjust transport congestion window
320 * @task: recently completed RPC request used to adjust window
321 * @result: result code of completed RPC request
323 * We use a time-smoothed congestion estimator to avoid heavy oscillation.
325 void xprt_adjust_cwnd(struct rpc_task *task, int result)
327 struct rpc_rqst *req = task->tk_rqstp;
328 struct rpc_xprt *xprt = task->tk_xprt;
329 unsigned long cwnd = xprt->cwnd;
331 if (result >= 0 && cwnd <= xprt->cong) {
332 /* The (cwnd >> 1) term makes sure
333 * the result gets rounded properly. */
334 cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd;
335 if (cwnd > RPC_MAXCWND(xprt))
336 cwnd = RPC_MAXCWND(xprt);
337 __xprt_lock_write_next_cong(xprt);
338 } else if (result == -ETIMEDOUT) {
340 if (cwnd < RPC_CWNDSCALE)
341 cwnd = RPC_CWNDSCALE;
343 dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n",
344 xprt->cong, xprt->cwnd, cwnd);
346 __xprt_put_cong(xprt, req);
350 * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue
351 * @xprt: transport with waiting tasks
352 * @status: result code to plant in each task before waking it
355 void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status)
358 rpc_wake_up_status(&xprt->pending, status);
360 rpc_wake_up(&xprt->pending);
364 * xprt_wait_for_buffer_space - wait for transport output buffer to clear
365 * @task: task to be put to sleep
368 void xprt_wait_for_buffer_space(struct rpc_task *task)
370 struct rpc_rqst *req = task->tk_rqstp;
371 struct rpc_xprt *xprt = req->rq_xprt;
373 task->tk_timeout = req->rq_timeout;
374 rpc_sleep_on(&xprt->pending, task, NULL, NULL);
378 * xprt_write_space - wake the task waiting for transport output buffer space
379 * @xprt: transport with waiting tasks
381 * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
383 void xprt_write_space(struct rpc_xprt *xprt)
385 if (unlikely(xprt->shutdown))
388 spin_lock_bh(&xprt->transport_lock);
389 if (xprt->snd_task) {
390 dprintk("RPC: write space: waking waiting task on xprt %p\n",
392 rpc_wake_up_task(xprt->snd_task);
394 spin_unlock_bh(&xprt->transport_lock);
398 * xprt_set_retrans_timeout_def - set a request's retransmit timeout
399 * @task: task whose timeout is to be set
401 * Set a request's retransmit timeout based on the transport's
402 * default timeout parameters. Used by transports that don't adjust
403 * the retransmit timeout based on round-trip time estimation.
405 void xprt_set_retrans_timeout_def(struct rpc_task *task)
407 task->tk_timeout = task->tk_rqstp->rq_timeout;
411 * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout
412 * @task: task whose timeout is to be set
414 * Set a request's retransmit timeout using the RTT estimator.
416 void xprt_set_retrans_timeout_rtt(struct rpc_task *task)
418 int timer = task->tk_msg.rpc_proc->p_timer;
419 struct rpc_rtt *rtt = task->tk_client->cl_rtt;
420 struct rpc_rqst *req = task->tk_rqstp;
421 unsigned long max_timeout = req->rq_xprt->timeout.to_maxval;
423 task->tk_timeout = rpc_calc_rto(rtt, timer);
424 task->tk_timeout <<= rpc_ntimeo(rtt, timer) + req->rq_retries;
425 if (task->tk_timeout > max_timeout || task->tk_timeout == 0)
426 task->tk_timeout = max_timeout;
429 static void xprt_reset_majortimeo(struct rpc_rqst *req)
431 struct rpc_timeout *to = &req->rq_xprt->timeout;
433 req->rq_majortimeo = req->rq_timeout;
434 if (to->to_exponential)
435 req->rq_majortimeo <<= to->to_retries;
437 req->rq_majortimeo += to->to_increment * to->to_retries;
438 if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0)
439 req->rq_majortimeo = to->to_maxval;
440 req->rq_majortimeo += jiffies;
444 * xprt_adjust_timeout - adjust timeout values for next retransmit
445 * @req: RPC request containing parameters to use for the adjustment
448 int xprt_adjust_timeout(struct rpc_rqst *req)
450 struct rpc_xprt *xprt = req->rq_xprt;
451 struct rpc_timeout *to = &xprt->timeout;
454 if (time_before(jiffies, req->rq_majortimeo)) {
455 if (to->to_exponential)
456 req->rq_timeout <<= 1;
458 req->rq_timeout += to->to_increment;
459 if (to->to_maxval && req->rq_timeout >= to->to_maxval)
460 req->rq_timeout = to->to_maxval;
463 req->rq_timeout = to->to_initval;
465 xprt_reset_majortimeo(req);
466 /* Reset the RTT counters == "slow start" */
467 spin_lock_bh(&xprt->transport_lock);
468 rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval);
469 spin_unlock_bh(&xprt->transport_lock);
473 if (req->rq_timeout == 0) {
474 printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n");
475 req->rq_timeout = 5 * HZ;
480 static void xprt_autoclose(void *args)
482 struct rpc_xprt *xprt = (struct rpc_xprt *)args;
484 xprt_disconnect(xprt);
485 xprt->ops->close(xprt);
486 xprt_release_write(xprt, NULL);
490 * xprt_disconnect - mark a transport as disconnected
491 * @xprt: transport to flag for disconnect
494 void xprt_disconnect(struct rpc_xprt *xprt)
496 dprintk("RPC: disconnected transport %p\n", xprt);
497 spin_lock_bh(&xprt->transport_lock);
498 xprt_clear_connected(xprt);
499 xprt_wake_pending_tasks(xprt, -ENOTCONN);
500 spin_unlock_bh(&xprt->transport_lock);
504 xprt_init_autodisconnect(unsigned long data)
506 struct rpc_xprt *xprt = (struct rpc_xprt *)data;
508 spin_lock(&xprt->transport_lock);
509 if (!list_empty(&xprt->recv) || xprt->shutdown)
511 if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
513 spin_unlock(&xprt->transport_lock);
514 if (xprt_connecting(xprt))
515 xprt_release_write(xprt, NULL);
517 schedule_work(&xprt->task_cleanup);
520 spin_unlock(&xprt->transport_lock);
524 * xprt_connect - schedule a transport connect operation
525 * @task: RPC task that is requesting the connect
528 void xprt_connect(struct rpc_task *task)
530 struct rpc_xprt *xprt = task->tk_xprt;
532 dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task->tk_pid,
533 xprt, (xprt_connected(xprt) ? "is" : "is not"));
535 if (!xprt_bound(xprt)) {
536 task->tk_status = -EIO;
539 if (!xprt_lock_write(xprt, task))
541 if (xprt_connected(xprt))
542 xprt_release_write(xprt, task);
545 task->tk_rqstp->rq_bytes_sent = 0;
547 task->tk_timeout = xprt->connect_timeout;
548 rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL);
549 xprt->stat.connect_start = jiffies;
550 xprt->ops->connect(task);
555 static void xprt_connect_status(struct rpc_task *task)
557 struct rpc_xprt *xprt = task->tk_xprt;
559 if (task->tk_status >= 0) {
560 xprt->stat.connect_count++;
561 xprt->stat.connect_time += (long)jiffies - xprt->stat.connect_start;
562 dprintk("RPC: %4d xprt_connect_status: connection established\n",
567 switch (task->tk_status) {
570 dprintk("RPC: %4d xprt_connect_status: server %s refused connection\n",
571 task->tk_pid, task->tk_client->cl_server);
574 dprintk("RPC: %4d xprt_connect_status: connection broken\n",
578 dprintk("RPC: %4d xprt_connect_status: connect attempt timed out\n",
582 dprintk("RPC: %4d xprt_connect_status: error %d connecting to server %s\n",
583 task->tk_pid, -task->tk_status, task->tk_client->cl_server);
584 xprt_release_write(xprt, task);
585 task->tk_status = -EIO;
590 * xprt_lookup_rqst - find an RPC request corresponding to an XID
591 * @xprt: transport on which the original request was transmitted
592 * @xid: RPC XID of incoming reply
595 struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid)
597 struct list_head *pos;
599 list_for_each(pos, &xprt->recv) {
600 struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list);
601 if (entry->rq_xid == xid)
604 xprt->stat.bad_xids++;
609 * xprt_update_rtt - update an RPC client's RTT state after receiving a reply
610 * @task: RPC request that recently completed
613 void xprt_update_rtt(struct rpc_task *task)
615 struct rpc_rqst *req = task->tk_rqstp;
616 struct rpc_rtt *rtt = task->tk_client->cl_rtt;
617 unsigned timer = task->tk_msg.rpc_proc->p_timer;
620 if (req->rq_ntrans == 1)
621 rpc_update_rtt(rtt, timer,
622 (long)jiffies - req->rq_xtime);
623 rpc_set_timeo(rtt, timer, req->rq_ntrans - 1);
628 * xprt_complete_rqst - called when reply processing is complete
629 * @task: RPC request that recently completed
630 * @copied: actual number of bytes received from the transport
632 * Caller holds transport lock.
634 void xprt_complete_rqst(struct rpc_task *task, int copied)
636 struct rpc_rqst *req = task->tk_rqstp;
638 dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
639 task->tk_pid, ntohl(req->rq_xid), copied);
641 task->tk_xprt->stat.recvs++;
642 task->tk_rtt = (long)jiffies - req->rq_xtime;
644 list_del_init(&req->rq_list);
645 /* Ensure all writes are done before we update req->rq_received */
647 req->rq_received = req->rq_private_buf.len = copied;
648 rpc_wake_up_task(task);
651 static void xprt_timer(struct rpc_task *task)
653 struct rpc_rqst *req = task->tk_rqstp;
654 struct rpc_xprt *xprt = req->rq_xprt;
656 dprintk("RPC: %4d xprt_timer\n", task->tk_pid);
658 spin_lock(&xprt->transport_lock);
659 if (!req->rq_received) {
660 if (xprt->ops->timer)
661 xprt->ops->timer(task);
662 task->tk_status = -ETIMEDOUT;
664 task->tk_timeout = 0;
665 rpc_wake_up_task(task);
666 spin_unlock(&xprt->transport_lock);
670 * xprt_prepare_transmit - reserve the transport before sending a request
671 * @task: RPC task about to send a request
674 int xprt_prepare_transmit(struct rpc_task *task)
676 struct rpc_rqst *req = task->tk_rqstp;
677 struct rpc_xprt *xprt = req->rq_xprt;
680 dprintk("RPC: %4d xprt_prepare_transmit\n", task->tk_pid);
682 spin_lock_bh(&xprt->transport_lock);
683 if (req->rq_received && !req->rq_bytes_sent) {
684 err = req->rq_received;
687 if (!xprt->ops->reserve_xprt(task)) {
692 if (!xprt_connected(xprt)) {
697 spin_unlock_bh(&xprt->transport_lock);
701 void xprt_end_transmit(struct rpc_task *task)
703 xprt_release_write(task->tk_xprt, task);
707 * xprt_transmit - send an RPC request on a transport
708 * @task: controlling RPC task
710 * We have to copy the iovec because sendmsg fiddles with its contents.
712 void xprt_transmit(struct rpc_task *task)
714 struct rpc_rqst *req = task->tk_rqstp;
715 struct rpc_xprt *xprt = req->rq_xprt;
718 dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
720 if (!req->rq_received) {
721 if (list_empty(&req->rq_list)) {
722 spin_lock_bh(&xprt->transport_lock);
723 /* Update the softirq receive buffer */
724 memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
725 sizeof(req->rq_private_buf));
726 /* Add request to the receive list */
727 list_add_tail(&req->rq_list, &xprt->recv);
728 spin_unlock_bh(&xprt->transport_lock);
729 xprt_reset_majortimeo(req);
730 /* Turn off autodisconnect */
731 del_singleshot_timer_sync(&xprt->timer);
733 } else if (!req->rq_bytes_sent)
736 status = xprt->ops->send_request(task);
738 dprintk("RPC: %4d xmit complete\n", task->tk_pid);
739 spin_lock_bh(&xprt->transport_lock);
741 xprt->ops->set_retrans_timeout(task);
744 xprt->stat.req_u += xprt->stat.sends - xprt->stat.recvs;
745 xprt->stat.bklog_u += xprt->backlog.qlen;
747 /* Don't race with disconnect */
748 if (!xprt_connected(xprt))
749 task->tk_status = -ENOTCONN;
750 else if (!req->rq_received)
751 rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);
752 spin_unlock_bh(&xprt->transport_lock);
756 /* Note: at this point, task->tk_sleeping has not yet been set,
757 * hence there is no danger of the waking up task being put on
758 * schedq, and being picked up by a parallel run of rpciod().
760 task->tk_status = status;
761 if (status == -ECONNREFUSED)
762 rpc_sleep_on(&xprt->sending, task, NULL, NULL);
765 static inline void do_xprt_reserve(struct rpc_task *task)
767 struct rpc_xprt *xprt = task->tk_xprt;
772 if (!list_empty(&xprt->free)) {
773 struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
774 list_del_init(&req->rq_list);
775 task->tk_rqstp = req;
776 xprt_request_init(task, xprt);
779 dprintk("RPC: waiting for request slot\n");
780 task->tk_status = -EAGAIN;
781 task->tk_timeout = 0;
782 rpc_sleep_on(&xprt->backlog, task, NULL, NULL);
786 * xprt_reserve - allocate an RPC request slot
787 * @task: RPC task requesting a slot allocation
789 * If no more slots are available, place the task on the transport's
792 void xprt_reserve(struct rpc_task *task)
794 struct rpc_xprt *xprt = task->tk_xprt;
796 task->tk_status = -EIO;
797 spin_lock(&xprt->reserve_lock);
798 do_xprt_reserve(task);
799 spin_unlock(&xprt->reserve_lock);
802 static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt)
807 static inline void xprt_init_xid(struct rpc_xprt *xprt)
809 xprt->xid = net_random();
812 static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
814 struct rpc_rqst *req = task->tk_rqstp;
816 req->rq_timeout = xprt->timeout.to_initval;
819 req->rq_buffer = NULL;
821 req->rq_xid = xprt_alloc_xid(xprt);
822 req->rq_release_snd_buf = NULL;
823 xprt_reset_majortimeo(req);
824 dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
825 req, ntohl(req->rq_xid));
829 * xprt_release - release an RPC request slot
830 * @task: task which is finished with the slot
833 void xprt_release(struct rpc_task *task)
835 struct rpc_xprt *xprt = task->tk_xprt;
836 struct rpc_rqst *req;
838 if (!(req = task->tk_rqstp))
840 rpc_count_iostats(task);
841 spin_lock_bh(&xprt->transport_lock);
842 xprt->ops->release_xprt(xprt, task);
843 if (xprt->ops->release_request)
844 xprt->ops->release_request(task);
845 if (!list_empty(&req->rq_list))
846 list_del(&req->rq_list);
847 xprt->last_used = jiffies;
848 if (list_empty(&xprt->recv))
849 mod_timer(&xprt->timer,
850 xprt->last_used + xprt->idle_timeout);
851 spin_unlock_bh(&xprt->transport_lock);
852 xprt->ops->buf_free(task);
853 task->tk_rqstp = NULL;
854 if (req->rq_release_snd_buf)
855 req->rq_release_snd_buf(req);
856 memset(req, 0, sizeof(*req)); /* mark unused */
858 dprintk("RPC: %4d release request %p\n", task->tk_pid, req);
860 spin_lock(&xprt->reserve_lock);
861 list_add(&req->rq_list, &xprt->free);
862 rpc_wake_up_next(&xprt->backlog);
863 spin_unlock(&xprt->reserve_lock);
867 * xprt_set_timeout - set constant RPC timeout
868 * @to: RPC timeout parameters to set up
869 * @retr: number of retries
870 * @incr: amount of increase after each retry
873 void xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr)
876 to->to_increment = incr;
877 to->to_maxval = to->to_initval + (incr * retr);
878 to->to_retries = retr;
879 to->to_exponential = 0;
883 * xprt_create_transport - create an RPC transport
884 * @proto: requested transport protocol
885 * @ap: remote peer address
886 * @size: length of address
887 * @to: timeout parameters
890 struct rpc_xprt *xprt_create_transport(int proto, struct sockaddr *ap, size_t size, struct rpc_timeout *to)
892 struct rpc_xprt *xprt;
893 struct rpc_rqst *req;
897 xprt = xs_setup_udp(ap, size, to);
900 xprt = xs_setup_tcp(ap, size, to);
903 printk(KERN_ERR "RPC: unrecognized transport protocol: %d\n",
905 return ERR_PTR(-EIO);
908 dprintk("RPC: xprt_create_transport: failed, %ld\n",
913 kref_init(&xprt->kref);
914 spin_lock_init(&xprt->transport_lock);
915 spin_lock_init(&xprt->reserve_lock);
917 INIT_LIST_HEAD(&xprt->free);
918 INIT_LIST_HEAD(&xprt->recv);
919 INIT_WORK(&xprt->task_cleanup, xprt_autoclose, xprt);
920 init_timer(&xprt->timer);
921 xprt->timer.function = xprt_init_autodisconnect;
922 xprt->timer.data = (unsigned long) xprt;
923 xprt->last_used = jiffies;
924 xprt->cwnd = RPC_INITCWND;
926 rpc_init_wait_queue(&xprt->binding, "xprt_binding");
927 rpc_init_wait_queue(&xprt->pending, "xprt_pending");
928 rpc_init_wait_queue(&xprt->sending, "xprt_sending");
929 rpc_init_wait_queue(&xprt->resend, "xprt_resend");
930 rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
932 /* initialize free list */
933 for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--)
934 list_add(&req->rq_list, &xprt->free);
938 dprintk("RPC: created transport %p with %u slots\n", xprt,
945 * xprt_destroy - destroy an RPC transport, killing off all requests.
946 * @kref: kref for the transport to destroy
949 static void xprt_destroy(struct kref *kref)
951 struct rpc_xprt *xprt = container_of(kref, struct rpc_xprt, kref);
953 dprintk("RPC: destroying transport %p\n", xprt);
955 del_timer_sync(&xprt->timer);
958 * Tear down transport state and free the rpc_xprt
960 xprt->ops->destroy(xprt);
964 * xprt_put - release a reference to an RPC transport.
965 * @xprt: pointer to the transport
968 void xprt_put(struct rpc_xprt *xprt)
970 kref_put(&xprt->kref, xprt_destroy);
974 * xprt_get - return a reference to an RPC transport.
975 * @xprt: pointer to the transport
978 struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
980 kref_get(&xprt->kref);