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/random.h>
46 #include <linux/sunrpc/clnt.h>
53 # undef RPC_DEBUG_DATA
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
);
123 * xprt_reserve_xprt_cong - serialize write access to transports
124 * @task: task that is requesting access to the transport
126 * Same as xprt_reserve_xprt, but Van Jacobson congestion control is
127 * integrated into the decision of whether a request is allowed to be
128 * woken up and given access to the transport.
130 int xprt_reserve_xprt_cong(struct rpc_task
*task
)
132 struct rpc_xprt
*xprt
= task
->tk_xprt
;
133 struct rpc_rqst
*req
= task
->tk_rqstp
;
135 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
)) {
136 if (task
== xprt
->snd_task
)
140 if (__xprt_get_cong(xprt
, task
)) {
141 xprt
->snd_task
= task
;
143 req
->rq_bytes_sent
= 0;
148 smp_mb__before_clear_bit();
149 clear_bit(XPRT_LOCKED
, &xprt
->state
);
150 smp_mb__after_clear_bit();
152 dprintk("RPC: %4d failed to lock transport %p\n", task
->tk_pid
, xprt
);
153 task
->tk_timeout
= 0;
154 task
->tk_status
= -EAGAIN
;
155 if (req
&& req
->rq_ntrans
)
156 rpc_sleep_on(&xprt
->resend
, task
, NULL
, NULL
);
158 rpc_sleep_on(&xprt
->sending
, task
, NULL
, NULL
);
162 static inline int xprt_lock_write(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
166 spin_lock_bh(&xprt
->transport_lock
);
167 retval
= xprt
->ops
->reserve_xprt(task
);
168 spin_unlock_bh(&xprt
->transport_lock
);
172 static void __xprt_lock_write_next(struct rpc_xprt
*xprt
)
174 struct rpc_task
*task
;
175 struct rpc_rqst
*req
;
177 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
))
180 task
= rpc_wake_up_next(&xprt
->resend
);
182 task
= rpc_wake_up_next(&xprt
->sending
);
187 req
= task
->tk_rqstp
;
188 xprt
->snd_task
= task
;
190 req
->rq_bytes_sent
= 0;
196 smp_mb__before_clear_bit();
197 clear_bit(XPRT_LOCKED
, &xprt
->state
);
198 smp_mb__after_clear_bit();
201 static void __xprt_lock_write_next_cong(struct rpc_xprt
*xprt
)
203 struct rpc_task
*task
;
205 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
))
207 if (RPCXPRT_CONGESTED(xprt
))
209 task
= rpc_wake_up_next(&xprt
->resend
);
211 task
= rpc_wake_up_next(&xprt
->sending
);
215 if (__xprt_get_cong(xprt
, task
)) {
216 struct rpc_rqst
*req
= task
->tk_rqstp
;
217 xprt
->snd_task
= task
;
219 req
->rq_bytes_sent
= 0;
225 smp_mb__before_clear_bit();
226 clear_bit(XPRT_LOCKED
, &xprt
->state
);
227 smp_mb__after_clear_bit();
231 * xprt_release_xprt - allow other requests to use a transport
232 * @xprt: transport with other tasks potentially waiting
233 * @task: task that is releasing access to the transport
235 * Note that "task" can be NULL. No congestion control is provided.
237 void xprt_release_xprt(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
239 if (xprt
->snd_task
== task
) {
240 xprt
->snd_task
= NULL
;
241 smp_mb__before_clear_bit();
242 clear_bit(XPRT_LOCKED
, &xprt
->state
);
243 smp_mb__after_clear_bit();
244 __xprt_lock_write_next(xprt
);
249 * xprt_release_xprt_cong - allow other requests to use a transport
250 * @xprt: transport with other tasks potentially waiting
251 * @task: task that is releasing access to the transport
253 * Note that "task" can be NULL. Another task is awoken to use the
254 * transport if the transport's congestion window allows it.
256 void xprt_release_xprt_cong(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
258 if (xprt
->snd_task
== task
) {
259 xprt
->snd_task
= NULL
;
260 smp_mb__before_clear_bit();
261 clear_bit(XPRT_LOCKED
, &xprt
->state
);
262 smp_mb__after_clear_bit();
263 __xprt_lock_write_next_cong(xprt
);
267 static inline void xprt_release_write(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
269 spin_lock_bh(&xprt
->transport_lock
);
270 xprt
->ops
->release_xprt(xprt
, task
);
271 spin_unlock_bh(&xprt
->transport_lock
);
275 * Van Jacobson congestion avoidance. Check if the congestion window
276 * overflowed. Put the task to sleep if this is the case.
279 __xprt_get_cong(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
281 struct rpc_rqst
*req
= task
->tk_rqstp
;
285 dprintk("RPC: %4d xprt_cwnd_limited cong = %ld cwnd = %ld\n",
286 task
->tk_pid
, xprt
->cong
, xprt
->cwnd
);
287 if (RPCXPRT_CONGESTED(xprt
))
290 xprt
->cong
+= RPC_CWNDSCALE
;
295 * Adjust the congestion window, and wake up the next task
296 * that has been sleeping due to congestion
299 __xprt_put_cong(struct rpc_xprt
*xprt
, struct rpc_rqst
*req
)
304 xprt
->cong
-= RPC_CWNDSCALE
;
305 __xprt_lock_write_next_cong(xprt
);
309 * xprt_release_rqst_cong - housekeeping when request is complete
310 * @task: RPC request that recently completed
312 * Useful for transports that require congestion control.
314 void xprt_release_rqst_cong(struct rpc_task
*task
)
316 __xprt_put_cong(task
->tk_xprt
, task
->tk_rqstp
);
320 * xprt_adjust_cwnd - adjust transport congestion window
321 * @task: recently completed RPC request used to adjust window
322 * @result: result code of completed RPC request
324 * We use a time-smoothed congestion estimator to avoid heavy oscillation.
326 void xprt_adjust_cwnd(struct rpc_task
*task
, int result
)
328 struct rpc_rqst
*req
= task
->tk_rqstp
;
329 struct rpc_xprt
*xprt
= task
->tk_xprt
;
330 unsigned long cwnd
= xprt
->cwnd
;
332 if (result
>= 0 && cwnd
<= xprt
->cong
) {
333 /* The (cwnd >> 1) term makes sure
334 * the result gets rounded properly. */
335 cwnd
+= (RPC_CWNDSCALE
* RPC_CWNDSCALE
+ (cwnd
>> 1)) / cwnd
;
336 if (cwnd
> RPC_MAXCWND(xprt
))
337 cwnd
= RPC_MAXCWND(xprt
);
338 __xprt_lock_write_next_cong(xprt
);
339 } else if (result
== -ETIMEDOUT
) {
341 if (cwnd
< RPC_CWNDSCALE
)
342 cwnd
= RPC_CWNDSCALE
;
344 dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n",
345 xprt
->cong
, xprt
->cwnd
, cwnd
);
347 __xprt_put_cong(xprt
, req
);
351 * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue
352 * @xprt: transport with waiting tasks
353 * @status: result code to plant in each task before waking it
356 void xprt_wake_pending_tasks(struct rpc_xprt
*xprt
, int status
)
359 rpc_wake_up_status(&xprt
->pending
, status
);
361 rpc_wake_up(&xprt
->pending
);
365 * xprt_wait_for_buffer_space - wait for transport output buffer to clear
366 * @task: task to be put to sleep
369 void xprt_wait_for_buffer_space(struct rpc_task
*task
)
371 struct rpc_rqst
*req
= task
->tk_rqstp
;
372 struct rpc_xprt
*xprt
= req
->rq_xprt
;
374 task
->tk_timeout
= req
->rq_timeout
;
375 rpc_sleep_on(&xprt
->pending
, task
, NULL
, NULL
);
379 * xprt_write_space - wake the task waiting for transport output buffer space
380 * @xprt: transport with waiting tasks
382 * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
384 void xprt_write_space(struct rpc_xprt
*xprt
)
386 if (unlikely(xprt
->shutdown
))
389 spin_lock_bh(&xprt
->transport_lock
);
390 if (xprt
->snd_task
) {
391 dprintk("RPC: write space: waking waiting task on xprt %p\n",
393 rpc_wake_up_task(xprt
->snd_task
);
395 spin_unlock_bh(&xprt
->transport_lock
);
399 * xprt_set_retrans_timeout_def - set a request's retransmit timeout
400 * @task: task whose timeout is to be set
402 * Set a request's retransmit timeout based on the transport's
403 * default timeout parameters. Used by transports that don't adjust
404 * the retransmit timeout based on round-trip time estimation.
406 void xprt_set_retrans_timeout_def(struct rpc_task
*task
)
408 task
->tk_timeout
= task
->tk_rqstp
->rq_timeout
;
412 * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout
413 * @task: task whose timeout is to be set
415 * Set a request's retransmit timeout using the RTT estimator.
417 void xprt_set_retrans_timeout_rtt(struct rpc_task
*task
)
419 int timer
= task
->tk_msg
.rpc_proc
->p_timer
;
420 struct rpc_rtt
*rtt
= task
->tk_client
->cl_rtt
;
421 struct rpc_rqst
*req
= task
->tk_rqstp
;
422 unsigned long max_timeout
= req
->rq_xprt
->timeout
.to_maxval
;
424 task
->tk_timeout
= rpc_calc_rto(rtt
, timer
);
425 task
->tk_timeout
<<= rpc_ntimeo(rtt
, timer
) + req
->rq_retries
;
426 if (task
->tk_timeout
> max_timeout
|| task
->tk_timeout
== 0)
427 task
->tk_timeout
= max_timeout
;
430 static void xprt_reset_majortimeo(struct rpc_rqst
*req
)
432 struct rpc_timeout
*to
= &req
->rq_xprt
->timeout
;
434 req
->rq_majortimeo
= req
->rq_timeout
;
435 if (to
->to_exponential
)
436 req
->rq_majortimeo
<<= to
->to_retries
;
438 req
->rq_majortimeo
+= to
->to_increment
* to
->to_retries
;
439 if (req
->rq_majortimeo
> to
->to_maxval
|| req
->rq_majortimeo
== 0)
440 req
->rq_majortimeo
= to
->to_maxval
;
441 req
->rq_majortimeo
+= jiffies
;
445 * xprt_adjust_timeout - adjust timeout values for next retransmit
446 * @req: RPC request containing parameters to use for the adjustment
449 int xprt_adjust_timeout(struct rpc_rqst
*req
)
451 struct rpc_xprt
*xprt
= req
->rq_xprt
;
452 struct rpc_timeout
*to
= &xprt
->timeout
;
455 if (time_before(jiffies
, req
->rq_majortimeo
)) {
456 if (to
->to_exponential
)
457 req
->rq_timeout
<<= 1;
459 req
->rq_timeout
+= to
->to_increment
;
460 if (to
->to_maxval
&& req
->rq_timeout
>= to
->to_maxval
)
461 req
->rq_timeout
= to
->to_maxval
;
463 pprintk("RPC: %lu retrans\n", jiffies
);
465 req
->rq_timeout
= to
->to_initval
;
467 xprt_reset_majortimeo(req
);
468 /* Reset the RTT counters == "slow start" */
469 spin_lock_bh(&xprt
->transport_lock
);
470 rpc_init_rtt(req
->rq_task
->tk_client
->cl_rtt
, to
->to_initval
);
471 spin_unlock_bh(&xprt
->transport_lock
);
472 pprintk("RPC: %lu timeout\n", jiffies
);
476 if (req
->rq_timeout
== 0) {
477 printk(KERN_WARNING
"xprt_adjust_timeout: rq_timeout = 0!\n");
478 req
->rq_timeout
= 5 * HZ
;
483 static void xprt_autoclose(void *args
)
485 struct rpc_xprt
*xprt
= (struct rpc_xprt
*)args
;
487 xprt_disconnect(xprt
);
488 xprt
->ops
->close(xprt
);
489 xprt_release_write(xprt
, NULL
);
493 * xprt_disconnect - mark a transport as disconnected
494 * @xprt: transport to flag for disconnect
497 void xprt_disconnect(struct rpc_xprt
*xprt
)
499 dprintk("RPC: disconnected transport %p\n", xprt
);
500 spin_lock_bh(&xprt
->transport_lock
);
501 xprt_clear_connected(xprt
);
502 xprt_wake_pending_tasks(xprt
, -ENOTCONN
);
503 spin_unlock_bh(&xprt
->transport_lock
);
507 xprt_init_autodisconnect(unsigned long data
)
509 struct rpc_xprt
*xprt
= (struct rpc_xprt
*)data
;
511 spin_lock(&xprt
->transport_lock
);
512 if (!list_empty(&xprt
->recv
) || xprt
->shutdown
)
514 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
))
516 spin_unlock(&xprt
->transport_lock
);
517 if (xprt_connecting(xprt
))
518 xprt_release_write(xprt
, NULL
);
520 schedule_work(&xprt
->task_cleanup
);
523 spin_unlock(&xprt
->transport_lock
);
527 * xprt_connect - schedule a transport connect operation
528 * @task: RPC task that is requesting the connect
531 void xprt_connect(struct rpc_task
*task
)
533 struct rpc_xprt
*xprt
= task
->tk_xprt
;
535 dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task
->tk_pid
,
536 xprt
, (xprt_connected(xprt
) ? "is" : "is not"));
538 if (xprt
->shutdown
) {
539 task
->tk_status
= -EIO
;
542 if (!xprt
->addr
.sin_port
) {
543 task
->tk_status
= -EIO
;
546 if (!xprt_lock_write(xprt
, task
))
548 if (xprt_connected(xprt
))
549 xprt_release_write(xprt
, task
);
552 task
->tk_rqstp
->rq_bytes_sent
= 0;
554 task
->tk_timeout
= xprt
->connect_timeout
;
555 rpc_sleep_on(&xprt
->pending
, task
, xprt_connect_status
, NULL
);
556 xprt
->ops
->connect(task
);
561 static void xprt_connect_status(struct rpc_task
*task
)
563 struct rpc_xprt
*xprt
= task
->tk_xprt
;
565 if (task
->tk_status
>= 0) {
566 dprintk("RPC: %4d xprt_connect_status: connection established\n",
571 switch (task
->tk_status
) {
574 dprintk("RPC: %4d xprt_connect_status: server %s refused connection\n",
575 task
->tk_pid
, task
->tk_client
->cl_server
);
578 dprintk("RPC: %4d xprt_connect_status: connection broken\n",
582 dprintk("RPC: %4d xprt_connect_status: connect attempt timed out\n",
586 dprintk("RPC: %4d xprt_connect_status: error %d connecting to server %s\n",
587 task
->tk_pid
, -task
->tk_status
, task
->tk_client
->cl_server
);
588 xprt_release_write(xprt
, task
);
589 task
->tk_status
= -EIO
;
593 /* if soft mounted, just cause this RPC to fail */
594 if (RPC_IS_SOFT(task
)) {
595 xprt_release_write(xprt
, task
);
596 task
->tk_status
= -EIO
;
601 * xprt_lookup_rqst - find an RPC request corresponding to an XID
602 * @xprt: transport on which the original request was transmitted
603 * @xid: RPC XID of incoming reply
606 struct rpc_rqst
*xprt_lookup_rqst(struct rpc_xprt
*xprt
, u32 xid
)
608 struct list_head
*pos
;
609 struct rpc_rqst
*req
= NULL
;
611 list_for_each(pos
, &xprt
->recv
) {
612 struct rpc_rqst
*entry
= list_entry(pos
, struct rpc_rqst
, rq_list
);
613 if (entry
->rq_xid
== xid
) {
622 * xprt_update_rtt - update an RPC client's RTT state after receiving a reply
623 * @task: RPC request that recently completed
626 void xprt_update_rtt(struct rpc_task
*task
)
628 struct rpc_rqst
*req
= task
->tk_rqstp
;
629 struct rpc_rtt
*rtt
= task
->tk_client
->cl_rtt
;
630 unsigned timer
= task
->tk_msg
.rpc_proc
->p_timer
;
633 if (req
->rq_ntrans
== 1)
634 rpc_update_rtt(rtt
, timer
,
635 (long)jiffies
- req
->rq_xtime
);
636 rpc_set_timeo(rtt
, timer
, req
->rq_ntrans
- 1);
641 * xprt_complete_rqst - called when reply processing is complete
642 * @task: RPC request that recently completed
643 * @copied: actual number of bytes received from the transport
645 * Caller holds transport lock.
647 void xprt_complete_rqst(struct rpc_task
*task
, int copied
)
649 struct rpc_rqst
*req
= task
->tk_rqstp
;
651 dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
652 task
->tk_pid
, ntohl(req
->rq_xid
), copied
);
654 list_del_init(&req
->rq_list
);
655 req
->rq_received
= req
->rq_private_buf
.len
= copied
;
656 rpc_wake_up_task(task
);
659 static void xprt_timer(struct rpc_task
*task
)
661 struct rpc_rqst
*req
= task
->tk_rqstp
;
662 struct rpc_xprt
*xprt
= req
->rq_xprt
;
664 dprintk("RPC: %4d xprt_timer\n", task
->tk_pid
);
666 spin_lock(&xprt
->transport_lock
);
667 if (!req
->rq_received
) {
668 if (xprt
->ops
->timer
)
669 xprt
->ops
->timer(task
);
670 task
->tk_status
= -ETIMEDOUT
;
672 task
->tk_timeout
= 0;
673 rpc_wake_up_task(task
);
674 spin_unlock(&xprt
->transport_lock
);
678 * xprt_prepare_transmit - reserve the transport before sending a request
679 * @task: RPC task about to send a request
682 int xprt_prepare_transmit(struct rpc_task
*task
)
684 struct rpc_rqst
*req
= task
->tk_rqstp
;
685 struct rpc_xprt
*xprt
= req
->rq_xprt
;
688 dprintk("RPC: %4d xprt_prepare_transmit\n", task
->tk_pid
);
693 spin_lock_bh(&xprt
->transport_lock
);
694 if (req
->rq_received
&& !req
->rq_bytes_sent
) {
695 err
= req
->rq_received
;
698 if (!xprt
->ops
->reserve_xprt(task
)) {
703 if (!xprt_connected(xprt
)) {
708 spin_unlock_bh(&xprt
->transport_lock
);
713 xprt_abort_transmit(struct rpc_task
*task
)
715 struct rpc_xprt
*xprt
= task
->tk_xprt
;
717 xprt_release_write(xprt
, task
);
721 * xprt_transmit - send an RPC request on a transport
722 * @task: controlling RPC task
724 * We have to copy the iovec because sendmsg fiddles with its contents.
726 void xprt_transmit(struct rpc_task
*task
)
728 struct rpc_rqst
*req
= task
->tk_rqstp
;
729 struct rpc_xprt
*xprt
= req
->rq_xprt
;
732 dprintk("RPC: %4d xprt_transmit(%u)\n", task
->tk_pid
, req
->rq_slen
);
735 if (!req
->rq_received
) {
736 if (list_empty(&req
->rq_list
)) {
737 spin_lock_bh(&xprt
->transport_lock
);
738 /* Update the softirq receive buffer */
739 memcpy(&req
->rq_private_buf
, &req
->rq_rcv_buf
,
740 sizeof(req
->rq_private_buf
));
741 /* Add request to the receive list */
742 list_add_tail(&req
->rq_list
, &xprt
->recv
);
743 spin_unlock_bh(&xprt
->transport_lock
);
744 xprt_reset_majortimeo(req
);
745 /* Turn off autodisconnect */
746 del_singleshot_timer_sync(&xprt
->timer
);
748 } else if (!req
->rq_bytes_sent
)
751 status
= xprt
->ops
->send_request(task
);
753 dprintk("RPC: %4d xmit complete\n", task
->tk_pid
);
754 spin_lock_bh(&xprt
->transport_lock
);
755 xprt
->ops
->set_retrans_timeout(task
);
756 /* Don't race with disconnect */
757 if (!xprt_connected(xprt
))
758 task
->tk_status
= -ENOTCONN
;
759 else if (!req
->rq_received
)
760 rpc_sleep_on(&xprt
->pending
, task
, NULL
, xprt_timer
);
761 xprt
->ops
->release_xprt(xprt
, task
);
762 spin_unlock_bh(&xprt
->transport_lock
);
766 /* Note: at this point, task->tk_sleeping has not yet been set,
767 * hence there is no danger of the waking up task being put on
768 * schedq, and being picked up by a parallel run of rpciod().
770 task
->tk_status
= status
;
774 rpc_sleep_on(&xprt
->sending
, task
, NULL
, NULL
);
781 xprt_release_write(xprt
, task
);
785 static inline void do_xprt_reserve(struct rpc_task
*task
)
787 struct rpc_xprt
*xprt
= task
->tk_xprt
;
792 if (!list_empty(&xprt
->free
)) {
793 struct rpc_rqst
*req
= list_entry(xprt
->free
.next
, struct rpc_rqst
, rq_list
);
794 list_del_init(&req
->rq_list
);
795 task
->tk_rqstp
= req
;
796 xprt_request_init(task
, xprt
);
799 dprintk("RPC: waiting for request slot\n");
800 task
->tk_status
= -EAGAIN
;
801 task
->tk_timeout
= 0;
802 rpc_sleep_on(&xprt
->backlog
, task
, NULL
, NULL
);
806 * xprt_reserve - allocate an RPC request slot
807 * @task: RPC task requesting a slot allocation
809 * If no more slots are available, place the task on the transport's
812 void xprt_reserve(struct rpc_task
*task
)
814 struct rpc_xprt
*xprt
= task
->tk_xprt
;
816 task
->tk_status
= -EIO
;
817 if (!xprt
->shutdown
) {
818 spin_lock(&xprt
->reserve_lock
);
819 do_xprt_reserve(task
);
820 spin_unlock(&xprt
->reserve_lock
);
824 static inline u32
xprt_alloc_xid(struct rpc_xprt
*xprt
)
829 static inline void xprt_init_xid(struct rpc_xprt
*xprt
)
831 get_random_bytes(&xprt
->xid
, sizeof(xprt
->xid
));
834 static void xprt_request_init(struct rpc_task
*task
, struct rpc_xprt
*xprt
)
836 struct rpc_rqst
*req
= task
->tk_rqstp
;
838 req
->rq_timeout
= xprt
->timeout
.to_initval
;
841 req
->rq_xid
= xprt_alloc_xid(xprt
);
842 req
->rq_release_snd_buf
= NULL
;
843 dprintk("RPC: %4d reserved req %p xid %08x\n", task
->tk_pid
,
844 req
, ntohl(req
->rq_xid
));
848 * xprt_release - release an RPC request slot
849 * @task: task which is finished with the slot
852 void xprt_release(struct rpc_task
*task
)
854 struct rpc_xprt
*xprt
= task
->tk_xprt
;
855 struct rpc_rqst
*req
;
857 if (!(req
= task
->tk_rqstp
))
859 spin_lock_bh(&xprt
->transport_lock
);
860 xprt
->ops
->release_xprt(xprt
, task
);
861 if (xprt
->ops
->release_request
)
862 xprt
->ops
->release_request(task
);
863 if (!list_empty(&req
->rq_list
))
864 list_del(&req
->rq_list
);
865 xprt
->last_used
= jiffies
;
866 if (list_empty(&xprt
->recv
) && !xprt
->shutdown
)
867 mod_timer(&xprt
->timer
,
868 xprt
->last_used
+ xprt
->idle_timeout
);
869 spin_unlock_bh(&xprt
->transport_lock
);
870 task
->tk_rqstp
= NULL
;
871 if (req
->rq_release_snd_buf
)
872 req
->rq_release_snd_buf(req
);
873 memset(req
, 0, sizeof(*req
)); /* mark unused */
875 dprintk("RPC: %4d release request %p\n", task
->tk_pid
, req
);
877 spin_lock(&xprt
->reserve_lock
);
878 list_add(&req
->rq_list
, &xprt
->free
);
879 rpc_wake_up_next(&xprt
->backlog
);
880 spin_unlock(&xprt
->reserve_lock
);
884 * xprt_set_timeout - set constant RPC timeout
885 * @to: RPC timeout parameters to set up
886 * @retr: number of retries
887 * @incr: amount of increase after each retry
890 void xprt_set_timeout(struct rpc_timeout
*to
, unsigned int retr
, unsigned long incr
)
893 to
->to_increment
= incr
;
894 to
->to_maxval
= to
->to_initval
+ (incr
* retr
);
895 to
->to_retries
= retr
;
896 to
->to_exponential
= 0;
899 static struct rpc_xprt
*xprt_setup(int proto
, struct sockaddr_in
*ap
, struct rpc_timeout
*to
)
902 struct rpc_xprt
*xprt
;
903 struct rpc_rqst
*req
;
905 if ((xprt
= kmalloc(sizeof(struct rpc_xprt
), GFP_KERNEL
)) == NULL
)
906 return ERR_PTR(-ENOMEM
);
907 memset(xprt
, 0, sizeof(*xprt
)); /* Nnnngh! */
913 result
= xs_setup_udp(xprt
, to
);
916 result
= xs_setup_tcp(xprt
, to
);
919 printk(KERN_ERR
"RPC: unrecognized transport protocol: %d\n",
926 return ERR_PTR(result
);
929 spin_lock_init(&xprt
->transport_lock
);
930 spin_lock_init(&xprt
->reserve_lock
);
932 INIT_LIST_HEAD(&xprt
->free
);
933 INIT_LIST_HEAD(&xprt
->recv
);
934 INIT_WORK(&xprt
->task_cleanup
, xprt_autoclose
, xprt
);
935 init_timer(&xprt
->timer
);
936 xprt
->timer
.function
= xprt_init_autodisconnect
;
937 xprt
->timer
.data
= (unsigned long) xprt
;
938 xprt
->last_used
= jiffies
;
939 xprt
->cwnd
= RPC_INITCWND
;
941 rpc_init_wait_queue(&xprt
->pending
, "xprt_pending");
942 rpc_init_wait_queue(&xprt
->sending
, "xprt_sending");
943 rpc_init_wait_queue(&xprt
->resend
, "xprt_resend");
944 rpc_init_priority_wait_queue(&xprt
->backlog
, "xprt_backlog");
946 /* initialize free list */
947 for (req
= &xprt
->slot
[xprt
->max_reqs
-1]; req
>= &xprt
->slot
[0]; req
--)
948 list_add(&req
->rq_list
, &xprt
->free
);
952 dprintk("RPC: created transport %p with %u slots\n", xprt
,
959 * xprt_create_proto - create an RPC client transport
960 * @proto: requested transport protocol
961 * @sap: remote peer's address
962 * @to: timeout parameters for new transport
965 struct rpc_xprt
*xprt_create_proto(int proto
, struct sockaddr_in
*sap
, struct rpc_timeout
*to
)
967 struct rpc_xprt
*xprt
;
969 xprt
= xprt_setup(proto
, sap
, to
);
971 dprintk("RPC: xprt_create_proto failed\n");
973 dprintk("RPC: xprt_create_proto created xprt %p\n", xprt
);
977 static void xprt_shutdown(struct rpc_xprt
*xprt
)
980 rpc_wake_up(&xprt
->sending
);
981 rpc_wake_up(&xprt
->resend
);
982 xprt_wake_pending_tasks(xprt
, -EIO
);
983 rpc_wake_up(&xprt
->backlog
);
984 del_timer_sync(&xprt
->timer
);
988 * xprt_destroy - destroy an RPC transport, killing off all requests.
989 * @xprt: transport to destroy
992 int xprt_destroy(struct rpc_xprt
*xprt
)
994 dprintk("RPC: destroying transport %p\n", xprt
);
996 xprt
->ops
->destroy(xprt
);