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, if a reply is expected,
16 * it installs a timer that is run after the packet's timeout has
18 * - When a packet arrives, the data_ready handler walks the list of
19 * pending requests for that transport. If a matching XID is found, the
20 * caller is woken up, and the timer removed.
21 * - When no reply arrives within the timeout interval, the timer is
22 * fired by the kernel and runs xprt_timer(). It either adjusts the
23 * timeout values (minor timeout) or wakes up the caller with a status
25 * - When the caller receives a notification from RPC that a reply arrived,
26 * it should release the RPC slot, and process the reply.
27 * If the call timed out, it may choose to retry the operation by
28 * adjusting the initial timeout value, and simply calling rpc_call
31 * Support for async RPC is done through a set of RPC-specific scheduling
32 * primitives that `transparently' work for processes as well as async
33 * tasks that rely on callbacks.
35 * Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de>
37 * Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com>
40 #include <linux/module.h>
42 #include <linux/types.h>
43 #include <linux/interrupt.h>
44 #include <linux/workqueue.h>
45 #include <linux/net.h>
46 #include <linux/ktime.h>
48 #include <linux/sunrpc/clnt.h>
49 #include <linux/sunrpc/metrics.h>
50 #include <linux/sunrpc/bc_xprt.h>
51 #include <linux/rcupdate.h>
53 #include <trace/events/sunrpc.h>
61 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
62 # define RPCDBG_FACILITY RPCDBG_XPRT
68 static void xprt_init(struct rpc_xprt
*xprt
, struct net
*net
);
69 static void xprt_request_init(struct rpc_task
*, struct rpc_xprt
*);
70 static void xprt_connect_status(struct rpc_task
*task
);
71 static int __xprt_get_cong(struct rpc_xprt
*, struct rpc_task
*);
72 static void __xprt_put_cong(struct rpc_xprt
*, struct rpc_rqst
*);
73 static void xprt_destroy(struct rpc_xprt
*xprt
);
75 static DEFINE_SPINLOCK(xprt_list_lock
);
76 static LIST_HEAD(xprt_list
);
79 * xprt_register_transport - register a transport implementation
80 * @transport: transport to register
82 * If a transport implementation is loaded as a kernel module, it can
83 * call this interface to make itself known to the RPC client.
86 * 0: transport successfully registered
87 * -EEXIST: transport already registered
88 * -EINVAL: transport module being unloaded
90 int xprt_register_transport(struct xprt_class
*transport
)
96 spin_lock(&xprt_list_lock
);
97 list_for_each_entry(t
, &xprt_list
, list
) {
98 /* don't register the same transport class twice */
99 if (t
->ident
== transport
->ident
)
103 list_add_tail(&transport
->list
, &xprt_list
);
104 printk(KERN_INFO
"RPC: Registered %s transport module.\n",
109 spin_unlock(&xprt_list_lock
);
112 EXPORT_SYMBOL_GPL(xprt_register_transport
);
115 * xprt_unregister_transport - unregister a transport implementation
116 * @transport: transport to unregister
119 * 0: transport successfully unregistered
120 * -ENOENT: transport never registered
122 int xprt_unregister_transport(struct xprt_class
*transport
)
124 struct xprt_class
*t
;
128 spin_lock(&xprt_list_lock
);
129 list_for_each_entry(t
, &xprt_list
, list
) {
130 if (t
== transport
) {
132 "RPC: Unregistered %s transport module.\n",
134 list_del_init(&transport
->list
);
141 spin_unlock(&xprt_list_lock
);
144 EXPORT_SYMBOL_GPL(xprt_unregister_transport
);
147 * xprt_load_transport - load a transport implementation
148 * @transport_name: transport to load
151 * 0: transport successfully loaded
152 * -ENOENT: transport module not available
154 int xprt_load_transport(const char *transport_name
)
156 struct xprt_class
*t
;
160 spin_lock(&xprt_list_lock
);
161 list_for_each_entry(t
, &xprt_list
, list
) {
162 if (strcmp(t
->name
, transport_name
) == 0) {
163 spin_unlock(&xprt_list_lock
);
167 spin_unlock(&xprt_list_lock
);
168 result
= request_module("xprt%s", transport_name
);
172 EXPORT_SYMBOL_GPL(xprt_load_transport
);
175 * xprt_reserve_xprt - serialize write access to transports
176 * @task: task that is requesting access to the transport
177 * @xprt: pointer to the target transport
179 * This prevents mixing the payload of separate requests, and prevents
180 * transport connects from colliding with writes. No congestion control
183 int xprt_reserve_xprt(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
185 struct rpc_rqst
*req
= task
->tk_rqstp
;
188 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
)) {
189 if (task
== xprt
->snd_task
)
193 xprt
->snd_task
= task
;
200 dprintk("RPC: %5u failed to lock transport %p\n",
202 task
->tk_timeout
= 0;
203 task
->tk_status
= -EAGAIN
;
205 priority
= RPC_PRIORITY_LOW
;
206 else if (!req
->rq_ntrans
)
207 priority
= RPC_PRIORITY_NORMAL
;
209 priority
= RPC_PRIORITY_HIGH
;
210 rpc_sleep_on_priority(&xprt
->sending
, task
, NULL
, priority
);
213 EXPORT_SYMBOL_GPL(xprt_reserve_xprt
);
215 static void xprt_clear_locked(struct rpc_xprt
*xprt
)
217 xprt
->snd_task
= NULL
;
218 if (!test_bit(XPRT_CLOSE_WAIT
, &xprt
->state
)) {
219 smp_mb__before_atomic();
220 clear_bit(XPRT_LOCKED
, &xprt
->state
);
221 smp_mb__after_atomic();
223 queue_work(xprtiod_workqueue
, &xprt
->task_cleanup
);
227 * xprt_reserve_xprt_cong - serialize write access to transports
228 * @task: task that is requesting access to the transport
230 * Same as xprt_reserve_xprt, but Van Jacobson congestion control is
231 * integrated into the decision of whether a request is allowed to be
232 * woken up and given access to the transport.
234 int xprt_reserve_xprt_cong(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
236 struct rpc_rqst
*req
= task
->tk_rqstp
;
239 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
)) {
240 if (task
== xprt
->snd_task
)
245 xprt
->snd_task
= task
;
248 if (__xprt_get_cong(xprt
, task
)) {
249 xprt
->snd_task
= task
;
253 xprt_clear_locked(xprt
);
256 __xprt_put_cong(xprt
, req
);
257 dprintk("RPC: %5u failed to lock transport %p\n", task
->tk_pid
, xprt
);
258 task
->tk_timeout
= 0;
259 task
->tk_status
= -EAGAIN
;
261 priority
= RPC_PRIORITY_LOW
;
262 else if (!req
->rq_ntrans
)
263 priority
= RPC_PRIORITY_NORMAL
;
265 priority
= RPC_PRIORITY_HIGH
;
266 rpc_sleep_on_priority(&xprt
->sending
, task
, NULL
, priority
);
269 EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong
);
271 static inline int xprt_lock_write(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
275 spin_lock_bh(&xprt
->transport_lock
);
276 retval
= xprt
->ops
->reserve_xprt(xprt
, task
);
277 spin_unlock_bh(&xprt
->transport_lock
);
281 static bool __xprt_lock_write_func(struct rpc_task
*task
, void *data
)
283 struct rpc_xprt
*xprt
= data
;
284 struct rpc_rqst
*req
;
286 req
= task
->tk_rqstp
;
287 xprt
->snd_task
= task
;
293 static void __xprt_lock_write_next(struct rpc_xprt
*xprt
)
295 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
))
298 if (rpc_wake_up_first_on_wq(xprtiod_workqueue
, &xprt
->sending
,
299 __xprt_lock_write_func
, xprt
))
301 xprt_clear_locked(xprt
);
304 static bool __xprt_lock_write_cong_func(struct rpc_task
*task
, void *data
)
306 struct rpc_xprt
*xprt
= data
;
307 struct rpc_rqst
*req
;
309 req
= task
->tk_rqstp
;
311 xprt
->snd_task
= task
;
314 if (__xprt_get_cong(xprt
, task
)) {
315 xprt
->snd_task
= task
;
322 static void __xprt_lock_write_next_cong(struct rpc_xprt
*xprt
)
324 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
))
326 if (RPCXPRT_CONGESTED(xprt
))
328 if (rpc_wake_up_first_on_wq(xprtiod_workqueue
, &xprt
->sending
,
329 __xprt_lock_write_cong_func
, xprt
))
332 xprt_clear_locked(xprt
);
335 static void xprt_task_clear_bytes_sent(struct rpc_task
*task
)
338 struct rpc_rqst
*req
= task
->tk_rqstp
;
340 req
->rq_bytes_sent
= 0;
345 * xprt_release_xprt - allow other requests to use a transport
346 * @xprt: transport with other tasks potentially waiting
347 * @task: task that is releasing access to the transport
349 * Note that "task" can be NULL. No congestion control is provided.
351 void xprt_release_xprt(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
353 if (xprt
->snd_task
== task
) {
354 xprt_task_clear_bytes_sent(task
);
355 xprt_clear_locked(xprt
);
356 __xprt_lock_write_next(xprt
);
359 EXPORT_SYMBOL_GPL(xprt_release_xprt
);
362 * xprt_release_xprt_cong - allow other requests to use a transport
363 * @xprt: transport with other tasks potentially waiting
364 * @task: task that is releasing access to the transport
366 * Note that "task" can be NULL. Another task is awoken to use the
367 * transport if the transport's congestion window allows it.
369 void xprt_release_xprt_cong(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
371 if (xprt
->snd_task
== task
) {
372 xprt_task_clear_bytes_sent(task
);
373 xprt_clear_locked(xprt
);
374 __xprt_lock_write_next_cong(xprt
);
377 EXPORT_SYMBOL_GPL(xprt_release_xprt_cong
);
379 static inline void xprt_release_write(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
381 spin_lock_bh(&xprt
->transport_lock
);
382 xprt
->ops
->release_xprt(xprt
, task
);
383 spin_unlock_bh(&xprt
->transport_lock
);
387 * Van Jacobson congestion avoidance. Check if the congestion window
388 * overflowed. Put the task to sleep if this is the case.
391 __xprt_get_cong(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
393 struct rpc_rqst
*req
= task
->tk_rqstp
;
397 dprintk("RPC: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\n",
398 task
->tk_pid
, xprt
->cong
, xprt
->cwnd
);
399 if (RPCXPRT_CONGESTED(xprt
))
402 xprt
->cong
+= RPC_CWNDSCALE
;
407 * Adjust the congestion window, and wake up the next task
408 * that has been sleeping due to congestion
411 __xprt_put_cong(struct rpc_xprt
*xprt
, struct rpc_rqst
*req
)
416 xprt
->cong
-= RPC_CWNDSCALE
;
417 __xprt_lock_write_next_cong(xprt
);
421 * xprt_release_rqst_cong - housekeeping when request is complete
422 * @task: RPC request that recently completed
424 * Useful for transports that require congestion control.
426 void xprt_release_rqst_cong(struct rpc_task
*task
)
428 struct rpc_rqst
*req
= task
->tk_rqstp
;
430 __xprt_put_cong(req
->rq_xprt
, req
);
432 EXPORT_SYMBOL_GPL(xprt_release_rqst_cong
);
435 * xprt_adjust_cwnd - adjust transport congestion window
436 * @xprt: pointer to xprt
437 * @task: recently completed RPC request used to adjust window
438 * @result: result code of completed RPC request
440 * The transport code maintains an estimate on the maximum number of out-
441 * standing RPC requests, using a smoothed version of the congestion
442 * avoidance implemented in 44BSD. This is basically the Van Jacobson
443 * congestion algorithm: If a retransmit occurs, the congestion window is
444 * halved; otherwise, it is incremented by 1/cwnd when
446 * - a reply is received and
447 * - a full number of requests are outstanding and
448 * - the congestion window hasn't been updated recently.
450 void xprt_adjust_cwnd(struct rpc_xprt
*xprt
, struct rpc_task
*task
, int result
)
452 struct rpc_rqst
*req
= task
->tk_rqstp
;
453 unsigned long cwnd
= xprt
->cwnd
;
455 if (result
>= 0 && cwnd
<= xprt
->cong
) {
456 /* The (cwnd >> 1) term makes sure
457 * the result gets rounded properly. */
458 cwnd
+= (RPC_CWNDSCALE
* RPC_CWNDSCALE
+ (cwnd
>> 1)) / cwnd
;
459 if (cwnd
> RPC_MAXCWND(xprt
))
460 cwnd
= RPC_MAXCWND(xprt
);
461 __xprt_lock_write_next_cong(xprt
);
462 } else if (result
== -ETIMEDOUT
) {
464 if (cwnd
< RPC_CWNDSCALE
)
465 cwnd
= RPC_CWNDSCALE
;
467 dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n",
468 xprt
->cong
, xprt
->cwnd
, cwnd
);
470 __xprt_put_cong(xprt
, req
);
472 EXPORT_SYMBOL_GPL(xprt_adjust_cwnd
);
475 * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue
476 * @xprt: transport with waiting tasks
477 * @status: result code to plant in each task before waking it
480 void xprt_wake_pending_tasks(struct rpc_xprt
*xprt
, int status
)
483 rpc_wake_up_status(&xprt
->pending
, status
);
485 rpc_wake_up(&xprt
->pending
);
487 EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks
);
490 * xprt_wait_for_buffer_space - wait for transport output buffer to clear
491 * @task: task to be put to sleep
492 * @action: function pointer to be executed after wait
494 * Note that we only set the timer for the case of RPC_IS_SOFT(), since
495 * we don't in general want to force a socket disconnection due to
496 * an incomplete RPC call transmission.
498 void xprt_wait_for_buffer_space(struct rpc_task
*task
, rpc_action action
)
500 struct rpc_rqst
*req
= task
->tk_rqstp
;
501 struct rpc_xprt
*xprt
= req
->rq_xprt
;
503 task
->tk_timeout
= RPC_IS_SOFT(task
) ? req
->rq_timeout
: 0;
504 rpc_sleep_on(&xprt
->pending
, task
, action
);
506 EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space
);
509 * xprt_write_space - wake the task waiting for transport output buffer space
510 * @xprt: transport with waiting tasks
512 * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
514 void xprt_write_space(struct rpc_xprt
*xprt
)
516 spin_lock_bh(&xprt
->transport_lock
);
517 if (xprt
->snd_task
) {
518 dprintk("RPC: write space: waking waiting task on "
520 rpc_wake_up_queued_task(&xprt
->pending
, xprt
->snd_task
);
522 spin_unlock_bh(&xprt
->transport_lock
);
524 EXPORT_SYMBOL_GPL(xprt_write_space
);
527 * xprt_set_retrans_timeout_def - set a request's retransmit timeout
528 * @task: task whose timeout is to be set
530 * Set a request's retransmit timeout based on the transport's
531 * default timeout parameters. Used by transports that don't adjust
532 * the retransmit timeout based on round-trip time estimation.
534 void xprt_set_retrans_timeout_def(struct rpc_task
*task
)
536 task
->tk_timeout
= task
->tk_rqstp
->rq_timeout
;
538 EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_def
);
541 * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout
542 * @task: task whose timeout is to be set
544 * Set a request's retransmit timeout using the RTT estimator.
546 void xprt_set_retrans_timeout_rtt(struct rpc_task
*task
)
548 int timer
= task
->tk_msg
.rpc_proc
->p_timer
;
549 struct rpc_clnt
*clnt
= task
->tk_client
;
550 struct rpc_rtt
*rtt
= clnt
->cl_rtt
;
551 struct rpc_rqst
*req
= task
->tk_rqstp
;
552 unsigned long max_timeout
= clnt
->cl_timeout
->to_maxval
;
554 task
->tk_timeout
= rpc_calc_rto(rtt
, timer
);
555 task
->tk_timeout
<<= rpc_ntimeo(rtt
, timer
) + req
->rq_retries
;
556 if (task
->tk_timeout
> max_timeout
|| task
->tk_timeout
== 0)
557 task
->tk_timeout
= max_timeout
;
559 EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_rtt
);
561 static void xprt_reset_majortimeo(struct rpc_rqst
*req
)
563 const struct rpc_timeout
*to
= req
->rq_task
->tk_client
->cl_timeout
;
565 req
->rq_majortimeo
= req
->rq_timeout
;
566 if (to
->to_exponential
)
567 req
->rq_majortimeo
<<= to
->to_retries
;
569 req
->rq_majortimeo
+= to
->to_increment
* to
->to_retries
;
570 if (req
->rq_majortimeo
> to
->to_maxval
|| req
->rq_majortimeo
== 0)
571 req
->rq_majortimeo
= to
->to_maxval
;
572 req
->rq_majortimeo
+= jiffies
;
576 * xprt_adjust_timeout - adjust timeout values for next retransmit
577 * @req: RPC request containing parameters to use for the adjustment
580 int xprt_adjust_timeout(struct rpc_rqst
*req
)
582 struct rpc_xprt
*xprt
= req
->rq_xprt
;
583 const struct rpc_timeout
*to
= req
->rq_task
->tk_client
->cl_timeout
;
586 if (time_before(jiffies
, req
->rq_majortimeo
)) {
587 if (to
->to_exponential
)
588 req
->rq_timeout
<<= 1;
590 req
->rq_timeout
+= to
->to_increment
;
591 if (to
->to_maxval
&& req
->rq_timeout
>= to
->to_maxval
)
592 req
->rq_timeout
= to
->to_maxval
;
595 req
->rq_timeout
= to
->to_initval
;
597 xprt_reset_majortimeo(req
);
598 /* Reset the RTT counters == "slow start" */
599 spin_lock_bh(&xprt
->transport_lock
);
600 rpc_init_rtt(req
->rq_task
->tk_client
->cl_rtt
, to
->to_initval
);
601 spin_unlock_bh(&xprt
->transport_lock
);
605 if (req
->rq_timeout
== 0) {
606 printk(KERN_WARNING
"xprt_adjust_timeout: rq_timeout = 0!\n");
607 req
->rq_timeout
= 5 * HZ
;
612 static void xprt_autoclose(struct work_struct
*work
)
614 struct rpc_xprt
*xprt
=
615 container_of(work
, struct rpc_xprt
, task_cleanup
);
617 clear_bit(XPRT_CLOSE_WAIT
, &xprt
->state
);
618 xprt
->ops
->close(xprt
);
619 xprt_release_write(xprt
, NULL
);
620 wake_up_bit(&xprt
->state
, XPRT_LOCKED
);
624 * xprt_disconnect_done - mark a transport as disconnected
625 * @xprt: transport to flag for disconnect
628 void xprt_disconnect_done(struct rpc_xprt
*xprt
)
630 dprintk("RPC: disconnected transport %p\n", xprt
);
631 spin_lock_bh(&xprt
->transport_lock
);
632 xprt_clear_connected(xprt
);
633 xprt_wake_pending_tasks(xprt
, -EAGAIN
);
634 spin_unlock_bh(&xprt
->transport_lock
);
636 EXPORT_SYMBOL_GPL(xprt_disconnect_done
);
639 * xprt_force_disconnect - force a transport to disconnect
640 * @xprt: transport to disconnect
643 void xprt_force_disconnect(struct rpc_xprt
*xprt
)
645 /* Don't race with the test_bit() in xprt_clear_locked() */
646 spin_lock_bh(&xprt
->transport_lock
);
647 set_bit(XPRT_CLOSE_WAIT
, &xprt
->state
);
648 /* Try to schedule an autoclose RPC call */
649 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
) == 0)
650 queue_work(xprtiod_workqueue
, &xprt
->task_cleanup
);
651 xprt_wake_pending_tasks(xprt
, -EAGAIN
);
652 spin_unlock_bh(&xprt
->transport_lock
);
656 * xprt_conditional_disconnect - force a transport to disconnect
657 * @xprt: transport to disconnect
658 * @cookie: 'connection cookie'
660 * This attempts to break the connection if and only if 'cookie' matches
661 * the current transport 'connection cookie'. It ensures that we don't
662 * try to break the connection more than once when we need to retransmit
663 * a batch of RPC requests.
666 void xprt_conditional_disconnect(struct rpc_xprt
*xprt
, unsigned int cookie
)
668 /* Don't race with the test_bit() in xprt_clear_locked() */
669 spin_lock_bh(&xprt
->transport_lock
);
670 if (cookie
!= xprt
->connect_cookie
)
672 if (test_bit(XPRT_CLOSING
, &xprt
->state
) || !xprt_connected(xprt
))
674 set_bit(XPRT_CLOSE_WAIT
, &xprt
->state
);
675 /* Try to schedule an autoclose RPC call */
676 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
) == 0)
677 queue_work(xprtiod_workqueue
, &xprt
->task_cleanup
);
678 xprt_wake_pending_tasks(xprt
, -EAGAIN
);
680 spin_unlock_bh(&xprt
->transport_lock
);
684 xprt_init_autodisconnect(unsigned long data
)
686 struct rpc_xprt
*xprt
= (struct rpc_xprt
*)data
;
688 spin_lock(&xprt
->transport_lock
);
689 if (!list_empty(&xprt
->recv
))
691 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
))
693 spin_unlock(&xprt
->transport_lock
);
694 queue_work(xprtiod_workqueue
, &xprt
->task_cleanup
);
697 spin_unlock(&xprt
->transport_lock
);
700 bool xprt_lock_connect(struct rpc_xprt
*xprt
,
701 struct rpc_task
*task
,
706 spin_lock_bh(&xprt
->transport_lock
);
707 if (!test_bit(XPRT_LOCKED
, &xprt
->state
))
709 if (xprt
->snd_task
!= task
)
711 xprt_task_clear_bytes_sent(task
);
712 xprt
->snd_task
= cookie
;
715 spin_unlock_bh(&xprt
->transport_lock
);
719 void xprt_unlock_connect(struct rpc_xprt
*xprt
, void *cookie
)
721 spin_lock_bh(&xprt
->transport_lock
);
722 if (xprt
->snd_task
!= cookie
)
724 if (!test_bit(XPRT_LOCKED
, &xprt
->state
))
726 xprt
->snd_task
=NULL
;
727 xprt
->ops
->release_xprt(xprt
, NULL
);
729 spin_unlock_bh(&xprt
->transport_lock
);
730 wake_up_bit(&xprt
->state
, XPRT_LOCKED
);
734 * xprt_connect - schedule a transport connect operation
735 * @task: RPC task that is requesting the connect
738 void xprt_connect(struct rpc_task
*task
)
740 struct rpc_xprt
*xprt
= task
->tk_rqstp
->rq_xprt
;
742 dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task
->tk_pid
,
743 xprt
, (xprt_connected(xprt
) ? "is" : "is not"));
745 if (!xprt_bound(xprt
)) {
746 task
->tk_status
= -EAGAIN
;
749 if (!xprt_lock_write(xprt
, task
))
752 if (test_and_clear_bit(XPRT_CLOSE_WAIT
, &xprt
->state
))
753 xprt
->ops
->close(xprt
);
755 if (!xprt_connected(xprt
)) {
756 task
->tk_rqstp
->rq_bytes_sent
= 0;
757 task
->tk_timeout
= task
->tk_rqstp
->rq_timeout
;
758 rpc_sleep_on(&xprt
->pending
, task
, xprt_connect_status
);
760 if (test_bit(XPRT_CLOSING
, &xprt
->state
))
762 if (xprt_test_and_set_connecting(xprt
))
764 xprt
->stat
.connect_start
= jiffies
;
765 xprt
->ops
->connect(xprt
, task
);
767 xprt_release_write(xprt
, task
);
770 static void xprt_connect_status(struct rpc_task
*task
)
772 struct rpc_xprt
*xprt
= task
->tk_rqstp
->rq_xprt
;
774 if (task
->tk_status
== 0) {
775 xprt
->stat
.connect_count
++;
776 xprt
->stat
.connect_time
+= (long)jiffies
- xprt
->stat
.connect_start
;
777 dprintk("RPC: %5u xprt_connect_status: connection established\n",
782 switch (task
->tk_status
) {
790 dprintk("RPC: %5u xprt_connect_status: retrying\n", task
->tk_pid
);
793 dprintk("RPC: %5u xprt_connect_status: connect attempt timed "
794 "out\n", task
->tk_pid
);
797 dprintk("RPC: %5u xprt_connect_status: error %d connecting to "
798 "server %s\n", task
->tk_pid
, -task
->tk_status
,
800 task
->tk_status
= -EIO
;
805 * xprt_lookup_rqst - find an RPC request corresponding to an XID
806 * @xprt: transport on which the original request was transmitted
807 * @xid: RPC XID of incoming reply
810 struct rpc_rqst
*xprt_lookup_rqst(struct rpc_xprt
*xprt
, __be32 xid
)
812 struct rpc_rqst
*entry
;
814 list_for_each_entry(entry
, &xprt
->recv
, rq_list
)
815 if (entry
->rq_xid
== xid
) {
816 trace_xprt_lookup_rqst(xprt
, xid
, 0);
820 dprintk("RPC: xprt_lookup_rqst did not find xid %08x\n",
822 trace_xprt_lookup_rqst(xprt
, xid
, -ENOENT
);
823 xprt
->stat
.bad_xids
++;
826 EXPORT_SYMBOL_GPL(xprt_lookup_rqst
);
828 static void xprt_update_rtt(struct rpc_task
*task
)
830 struct rpc_rqst
*req
= task
->tk_rqstp
;
831 struct rpc_rtt
*rtt
= task
->tk_client
->cl_rtt
;
832 unsigned int timer
= task
->tk_msg
.rpc_proc
->p_timer
;
833 long m
= usecs_to_jiffies(ktime_to_us(req
->rq_rtt
));
836 if (req
->rq_ntrans
== 1)
837 rpc_update_rtt(rtt
, timer
, m
);
838 rpc_set_timeo(rtt
, timer
, req
->rq_ntrans
- 1);
843 * xprt_complete_rqst - called when reply processing is complete
844 * @task: RPC request that recently completed
845 * @copied: actual number of bytes received from the transport
847 * Caller holds transport lock.
849 void xprt_complete_rqst(struct rpc_task
*task
, int copied
)
851 struct rpc_rqst
*req
= task
->tk_rqstp
;
852 struct rpc_xprt
*xprt
= req
->rq_xprt
;
854 dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
855 task
->tk_pid
, ntohl(req
->rq_xid
), copied
);
856 trace_xprt_complete_rqst(xprt
, req
->rq_xid
, copied
);
859 req
->rq_rtt
= ktime_sub(ktime_get(), req
->rq_xtime
);
860 if (xprt
->ops
->timer
!= NULL
)
861 xprt_update_rtt(task
);
863 list_del_init(&req
->rq_list
);
864 req
->rq_private_buf
.len
= copied
;
865 /* Ensure all writes are done before we update */
866 /* req->rq_reply_bytes_recvd */
868 req
->rq_reply_bytes_recvd
= copied
;
869 rpc_wake_up_queued_task(&xprt
->pending
, task
);
871 EXPORT_SYMBOL_GPL(xprt_complete_rqst
);
873 static void xprt_timer(struct rpc_task
*task
)
875 struct rpc_rqst
*req
= task
->tk_rqstp
;
876 struct rpc_xprt
*xprt
= req
->rq_xprt
;
878 if (task
->tk_status
!= -ETIMEDOUT
)
880 dprintk("RPC: %5u xprt_timer\n", task
->tk_pid
);
882 spin_lock_bh(&xprt
->transport_lock
);
883 if (!req
->rq_reply_bytes_recvd
) {
884 if (xprt
->ops
->timer
)
885 xprt
->ops
->timer(xprt
, task
);
888 spin_unlock_bh(&xprt
->transport_lock
);
891 static inline int xprt_has_timer(struct rpc_xprt
*xprt
)
893 return xprt
->idle_timeout
!= 0;
897 * xprt_prepare_transmit - reserve the transport before sending a request
898 * @task: RPC task about to send a request
901 bool xprt_prepare_transmit(struct rpc_task
*task
)
903 struct rpc_rqst
*req
= task
->tk_rqstp
;
904 struct rpc_xprt
*xprt
= req
->rq_xprt
;
907 dprintk("RPC: %5u xprt_prepare_transmit\n", task
->tk_pid
);
909 spin_lock_bh(&xprt
->transport_lock
);
910 if (!req
->rq_bytes_sent
) {
911 if (req
->rq_reply_bytes_recvd
) {
912 task
->tk_status
= req
->rq_reply_bytes_recvd
;
915 if ((task
->tk_flags
& RPC_TASK_NO_RETRANS_TIMEOUT
)
916 && xprt_connected(xprt
)
917 && req
->rq_connect_cookie
== xprt
->connect_cookie
) {
918 xprt
->ops
->set_retrans_timeout(task
);
919 rpc_sleep_on(&xprt
->pending
, task
, xprt_timer
);
923 if (!xprt
->ops
->reserve_xprt(xprt
, task
)) {
924 task
->tk_status
= -EAGAIN
;
929 spin_unlock_bh(&xprt
->transport_lock
);
933 void xprt_end_transmit(struct rpc_task
*task
)
935 xprt_release_write(task
->tk_rqstp
->rq_xprt
, task
);
939 * xprt_transmit - send an RPC request on a transport
940 * @task: controlling RPC task
942 * We have to copy the iovec because sendmsg fiddles with its contents.
944 void xprt_transmit(struct rpc_task
*task
)
946 struct rpc_rqst
*req
= task
->tk_rqstp
;
947 struct rpc_xprt
*xprt
= req
->rq_xprt
;
950 dprintk("RPC: %5u xprt_transmit(%u)\n", task
->tk_pid
, req
->rq_slen
);
952 if (!req
->rq_reply_bytes_recvd
) {
953 if (list_empty(&req
->rq_list
) && rpc_reply_expected(task
)) {
955 * Add to the list only if we're expecting a reply
957 spin_lock_bh(&xprt
->transport_lock
);
958 /* Update the softirq receive buffer */
959 memcpy(&req
->rq_private_buf
, &req
->rq_rcv_buf
,
960 sizeof(req
->rq_private_buf
));
961 /* Add request to the receive list */
962 list_add_tail(&req
->rq_list
, &xprt
->recv
);
963 spin_unlock_bh(&xprt
->transport_lock
);
964 xprt_reset_majortimeo(req
);
965 /* Turn off autodisconnect */
966 del_singleshot_timer_sync(&xprt
->timer
);
968 } else if (!req
->rq_bytes_sent
)
971 req
->rq_xtime
= ktime_get();
972 status
= xprt
->ops
->send_request(task
);
973 trace_xprt_transmit(xprt
, req
->rq_xid
, status
);
975 task
->tk_status
= status
;
978 xprt_inject_disconnect(xprt
);
980 dprintk("RPC: %5u xmit complete\n", task
->tk_pid
);
981 task
->tk_flags
|= RPC_TASK_SENT
;
982 spin_lock_bh(&xprt
->transport_lock
);
984 xprt
->ops
->set_retrans_timeout(task
);
986 numreqs
= atomic_read(&xprt
->num_reqs
);
987 if (numreqs
> xprt
->stat
.max_slots
)
988 xprt
->stat
.max_slots
= numreqs
;
990 xprt
->stat
.req_u
+= xprt
->stat
.sends
- xprt
->stat
.recvs
;
991 xprt
->stat
.bklog_u
+= xprt
->backlog
.qlen
;
992 xprt
->stat
.sending_u
+= xprt
->sending
.qlen
;
993 xprt
->stat
.pending_u
+= xprt
->pending
.qlen
;
995 /* Don't race with disconnect */
996 if (!xprt_connected(xprt
))
997 task
->tk_status
= -ENOTCONN
;
1000 * Sleep on the pending queue since
1001 * we're expecting a reply.
1003 if (!req
->rq_reply_bytes_recvd
&& rpc_reply_expected(task
))
1004 rpc_sleep_on(&xprt
->pending
, task
, xprt_timer
);
1005 req
->rq_connect_cookie
= xprt
->connect_cookie
;
1007 spin_unlock_bh(&xprt
->transport_lock
);
1010 static void xprt_add_backlog(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
1012 set_bit(XPRT_CONGESTED
, &xprt
->state
);
1013 rpc_sleep_on(&xprt
->backlog
, task
, NULL
);
1016 static void xprt_wake_up_backlog(struct rpc_xprt
*xprt
)
1018 if (rpc_wake_up_next(&xprt
->backlog
) == NULL
)
1019 clear_bit(XPRT_CONGESTED
, &xprt
->state
);
1022 static bool xprt_throttle_congested(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
1026 if (!test_bit(XPRT_CONGESTED
, &xprt
->state
))
1028 spin_lock(&xprt
->reserve_lock
);
1029 if (test_bit(XPRT_CONGESTED
, &xprt
->state
)) {
1030 rpc_sleep_on(&xprt
->backlog
, task
, NULL
);
1033 spin_unlock(&xprt
->reserve_lock
);
1038 static struct rpc_rqst
*xprt_dynamic_alloc_slot(struct rpc_xprt
*xprt
, gfp_t gfp_flags
)
1040 struct rpc_rqst
*req
= ERR_PTR(-EAGAIN
);
1042 if (!atomic_add_unless(&xprt
->num_reqs
, 1, xprt
->max_reqs
))
1044 req
= kzalloc(sizeof(struct rpc_rqst
), gfp_flags
);
1047 atomic_dec(&xprt
->num_reqs
);
1048 req
= ERR_PTR(-ENOMEM
);
1053 static bool xprt_dynamic_free_slot(struct rpc_xprt
*xprt
, struct rpc_rqst
*req
)
1055 if (atomic_add_unless(&xprt
->num_reqs
, -1, xprt
->min_reqs
)) {
1062 void xprt_alloc_slot(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
1064 struct rpc_rqst
*req
;
1066 spin_lock(&xprt
->reserve_lock
);
1067 if (!list_empty(&xprt
->free
)) {
1068 req
= list_entry(xprt
->free
.next
, struct rpc_rqst
, rq_list
);
1069 list_del(&req
->rq_list
);
1072 req
= xprt_dynamic_alloc_slot(xprt
, GFP_NOWAIT
|__GFP_NOWARN
);
1075 switch (PTR_ERR(req
)) {
1077 dprintk("RPC: dynamic allocation of request slot "
1078 "failed! Retrying\n");
1079 task
->tk_status
= -ENOMEM
;
1082 xprt_add_backlog(xprt
, task
);
1083 dprintk("RPC: waiting for request slot\n");
1085 task
->tk_status
= -EAGAIN
;
1087 spin_unlock(&xprt
->reserve_lock
);
1090 task
->tk_status
= 0;
1091 task
->tk_rqstp
= req
;
1092 xprt_request_init(task
, xprt
);
1093 spin_unlock(&xprt
->reserve_lock
);
1095 EXPORT_SYMBOL_GPL(xprt_alloc_slot
);
1097 void xprt_lock_and_alloc_slot(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
1099 /* Note: grabbing the xprt_lock_write() ensures that we throttle
1100 * new slot allocation if the transport is congested (i.e. when
1101 * reconnecting a stream transport or when out of socket write
1104 if (xprt_lock_write(xprt
, task
)) {
1105 xprt_alloc_slot(xprt
, task
);
1106 xprt_release_write(xprt
, task
);
1109 EXPORT_SYMBOL_GPL(xprt_lock_and_alloc_slot
);
1111 static void xprt_free_slot(struct rpc_xprt
*xprt
, struct rpc_rqst
*req
)
1113 spin_lock(&xprt
->reserve_lock
);
1114 if (!xprt_dynamic_free_slot(xprt
, req
)) {
1115 memset(req
, 0, sizeof(*req
)); /* mark unused */
1116 list_add(&req
->rq_list
, &xprt
->free
);
1118 xprt_wake_up_backlog(xprt
);
1119 spin_unlock(&xprt
->reserve_lock
);
1122 static void xprt_free_all_slots(struct rpc_xprt
*xprt
)
1124 struct rpc_rqst
*req
;
1125 while (!list_empty(&xprt
->free
)) {
1126 req
= list_first_entry(&xprt
->free
, struct rpc_rqst
, rq_list
);
1127 list_del(&req
->rq_list
);
1132 struct rpc_xprt
*xprt_alloc(struct net
*net
, size_t size
,
1133 unsigned int num_prealloc
,
1134 unsigned int max_alloc
)
1136 struct rpc_xprt
*xprt
;
1137 struct rpc_rqst
*req
;
1140 xprt
= kzalloc(size
, GFP_KERNEL
);
1144 xprt_init(xprt
, net
);
1146 for (i
= 0; i
< num_prealloc
; i
++) {
1147 req
= kzalloc(sizeof(struct rpc_rqst
), GFP_KERNEL
);
1150 list_add(&req
->rq_list
, &xprt
->free
);
1152 if (max_alloc
> num_prealloc
)
1153 xprt
->max_reqs
= max_alloc
;
1155 xprt
->max_reqs
= num_prealloc
;
1156 xprt
->min_reqs
= num_prealloc
;
1157 atomic_set(&xprt
->num_reqs
, num_prealloc
);
1166 EXPORT_SYMBOL_GPL(xprt_alloc
);
1168 void xprt_free(struct rpc_xprt
*xprt
)
1170 put_net(xprt
->xprt_net
);
1171 xprt_free_all_slots(xprt
);
1172 kfree_rcu(xprt
, rcu
);
1174 EXPORT_SYMBOL_GPL(xprt_free
);
1177 * xprt_reserve - allocate an RPC request slot
1178 * @task: RPC task requesting a slot allocation
1180 * If the transport is marked as being congested, or if no more
1181 * slots are available, place the task on the transport's
1184 void xprt_reserve(struct rpc_task
*task
)
1186 struct rpc_xprt
*xprt
= task
->tk_xprt
;
1188 task
->tk_status
= 0;
1189 if (task
->tk_rqstp
!= NULL
)
1192 task
->tk_timeout
= 0;
1193 task
->tk_status
= -EAGAIN
;
1194 if (!xprt_throttle_congested(xprt
, task
))
1195 xprt
->ops
->alloc_slot(xprt
, task
);
1199 * xprt_retry_reserve - allocate an RPC request slot
1200 * @task: RPC task requesting a slot allocation
1202 * If no more slots are available, place the task on the transport's
1204 * Note that the only difference with xprt_reserve is that we now
1205 * ignore the value of the XPRT_CONGESTED flag.
1207 void xprt_retry_reserve(struct rpc_task
*task
)
1209 struct rpc_xprt
*xprt
= task
->tk_xprt
;
1211 task
->tk_status
= 0;
1212 if (task
->tk_rqstp
!= NULL
)
1215 task
->tk_timeout
= 0;
1216 task
->tk_status
= -EAGAIN
;
1217 xprt
->ops
->alloc_slot(xprt
, task
);
1220 static inline __be32
xprt_alloc_xid(struct rpc_xprt
*xprt
)
1222 return (__force __be32
)xprt
->xid
++;
1225 static inline void xprt_init_xid(struct rpc_xprt
*xprt
)
1227 xprt
->xid
= prandom_u32();
1230 static void xprt_request_init(struct rpc_task
*task
, struct rpc_xprt
*xprt
)
1232 struct rpc_rqst
*req
= task
->tk_rqstp
;
1234 INIT_LIST_HEAD(&req
->rq_list
);
1235 req
->rq_timeout
= task
->tk_client
->cl_timeout
->to_initval
;
1236 req
->rq_task
= task
;
1237 req
->rq_xprt
= xprt
;
1238 req
->rq_buffer
= NULL
;
1239 req
->rq_xid
= xprt_alloc_xid(xprt
);
1240 req
->rq_connect_cookie
= xprt
->connect_cookie
- 1;
1241 req
->rq_bytes_sent
= 0;
1242 req
->rq_snd_buf
.len
= 0;
1243 req
->rq_snd_buf
.buflen
= 0;
1244 req
->rq_rcv_buf
.len
= 0;
1245 req
->rq_rcv_buf
.buflen
= 0;
1246 req
->rq_release_snd_buf
= NULL
;
1247 xprt_reset_majortimeo(req
);
1248 dprintk("RPC: %5u reserved req %p xid %08x\n", task
->tk_pid
,
1249 req
, ntohl(req
->rq_xid
));
1253 * xprt_release - release an RPC request slot
1254 * @task: task which is finished with the slot
1257 void xprt_release(struct rpc_task
*task
)
1259 struct rpc_xprt
*xprt
;
1260 struct rpc_rqst
*req
= task
->tk_rqstp
;
1263 if (task
->tk_client
) {
1264 xprt
= task
->tk_xprt
;
1265 if (xprt
->snd_task
== task
)
1266 xprt_release_write(xprt
, task
);
1271 xprt
= req
->rq_xprt
;
1272 if (task
->tk_ops
->rpc_count_stats
!= NULL
)
1273 task
->tk_ops
->rpc_count_stats(task
, task
->tk_calldata
);
1274 else if (task
->tk_client
)
1275 rpc_count_iostats(task
, task
->tk_client
->cl_metrics
);
1276 spin_lock_bh(&xprt
->transport_lock
);
1277 xprt
->ops
->release_xprt(xprt
, task
);
1278 if (xprt
->ops
->release_request
)
1279 xprt
->ops
->release_request(task
);
1280 if (!list_empty(&req
->rq_list
))
1281 list_del(&req
->rq_list
);
1282 xprt
->last_used
= jiffies
;
1283 if (list_empty(&xprt
->recv
) && xprt_has_timer(xprt
))
1284 mod_timer(&xprt
->timer
,
1285 xprt
->last_used
+ xprt
->idle_timeout
);
1286 spin_unlock_bh(&xprt
->transport_lock
);
1288 xprt
->ops
->buf_free(req
->rq_buffer
);
1289 xprt_inject_disconnect(xprt
);
1290 if (req
->rq_cred
!= NULL
)
1291 put_rpccred(req
->rq_cred
);
1292 task
->tk_rqstp
= NULL
;
1293 if (req
->rq_release_snd_buf
)
1294 req
->rq_release_snd_buf(req
);
1296 dprintk("RPC: %5u release request %p\n", task
->tk_pid
, req
);
1297 if (likely(!bc_prealloc(req
)))
1298 xprt_free_slot(xprt
, req
);
1300 xprt_free_bc_request(req
);
1303 static void xprt_init(struct rpc_xprt
*xprt
, struct net
*net
)
1305 kref_init(&xprt
->kref
);
1307 spin_lock_init(&xprt
->transport_lock
);
1308 spin_lock_init(&xprt
->reserve_lock
);
1310 INIT_LIST_HEAD(&xprt
->free
);
1311 INIT_LIST_HEAD(&xprt
->recv
);
1312 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1313 spin_lock_init(&xprt
->bc_pa_lock
);
1314 INIT_LIST_HEAD(&xprt
->bc_pa_list
);
1315 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1316 INIT_LIST_HEAD(&xprt
->xprt_switch
);
1318 xprt
->last_used
= jiffies
;
1319 xprt
->cwnd
= RPC_INITCWND
;
1320 xprt
->bind_index
= 0;
1322 rpc_init_wait_queue(&xprt
->binding
, "xprt_binding");
1323 rpc_init_wait_queue(&xprt
->pending
, "xprt_pending");
1324 rpc_init_priority_wait_queue(&xprt
->sending
, "xprt_sending");
1325 rpc_init_priority_wait_queue(&xprt
->backlog
, "xprt_backlog");
1327 xprt_init_xid(xprt
);
1329 xprt
->xprt_net
= get_net(net
);
1333 * xprt_create_transport - create an RPC transport
1334 * @args: rpc transport creation arguments
1337 struct rpc_xprt
*xprt_create_transport(struct xprt_create
*args
)
1339 struct rpc_xprt
*xprt
;
1340 struct xprt_class
*t
;
1342 spin_lock(&xprt_list_lock
);
1343 list_for_each_entry(t
, &xprt_list
, list
) {
1344 if (t
->ident
== args
->ident
) {
1345 spin_unlock(&xprt_list_lock
);
1349 spin_unlock(&xprt_list_lock
);
1350 dprintk("RPC: transport (%d) not supported\n", args
->ident
);
1351 return ERR_PTR(-EIO
);
1354 xprt
= t
->setup(args
);
1356 dprintk("RPC: xprt_create_transport: failed, %ld\n",
1360 if (args
->flags
& XPRT_CREATE_NO_IDLE_TIMEOUT
)
1361 xprt
->idle_timeout
= 0;
1362 INIT_WORK(&xprt
->task_cleanup
, xprt_autoclose
);
1363 if (xprt_has_timer(xprt
))
1364 setup_timer(&xprt
->timer
, xprt_init_autodisconnect
,
1365 (unsigned long)xprt
);
1367 init_timer(&xprt
->timer
);
1369 if (strlen(args
->servername
) > RPC_MAXNETNAMELEN
) {
1371 return ERR_PTR(-EINVAL
);
1373 xprt
->servername
= kstrdup(args
->servername
, GFP_KERNEL
);
1374 if (xprt
->servername
== NULL
) {
1376 return ERR_PTR(-ENOMEM
);
1379 rpc_xprt_debugfs_register(xprt
);
1381 dprintk("RPC: created transport %p with %u slots\n", xprt
,
1388 * xprt_destroy - destroy an RPC transport, killing off all requests.
1389 * @xprt: transport to destroy
1392 static void xprt_destroy(struct rpc_xprt
*xprt
)
1394 dprintk("RPC: destroying transport %p\n", xprt
);
1396 /* Exclude transport connect/disconnect handlers */
1397 wait_on_bit_lock(&xprt
->state
, XPRT_LOCKED
, TASK_UNINTERRUPTIBLE
);
1399 del_timer_sync(&xprt
->timer
);
1401 rpc_xprt_debugfs_unregister(xprt
);
1402 rpc_destroy_wait_queue(&xprt
->binding
);
1403 rpc_destroy_wait_queue(&xprt
->pending
);
1404 rpc_destroy_wait_queue(&xprt
->sending
);
1405 rpc_destroy_wait_queue(&xprt
->backlog
);
1406 cancel_work_sync(&xprt
->task_cleanup
);
1407 kfree(xprt
->servername
);
1409 * Tear down transport state and free the rpc_xprt
1411 xprt
->ops
->destroy(xprt
);
1414 static void xprt_destroy_kref(struct kref
*kref
)
1416 xprt_destroy(container_of(kref
, struct rpc_xprt
, kref
));
1420 * xprt_get - return a reference to an RPC transport.
1421 * @xprt: pointer to the transport
1424 struct rpc_xprt
*xprt_get(struct rpc_xprt
*xprt
)
1426 if (xprt
!= NULL
&& kref_get_unless_zero(&xprt
->kref
))
1430 EXPORT_SYMBOL_GPL(xprt_get
);
1433 * xprt_put - release a reference to an RPC transport.
1434 * @xprt: pointer to the transport
1437 void xprt_put(struct rpc_xprt
*xprt
)
1440 kref_put(&xprt
->kref
, xprt_destroy_kref
);
1442 EXPORT_SYMBOL_GPL(xprt_put
);