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
);
654 EXPORT_SYMBOL_GPL(xprt_force_disconnect
);
657 * xprt_conditional_disconnect - force a transport to disconnect
658 * @xprt: transport to disconnect
659 * @cookie: 'connection cookie'
661 * This attempts to break the connection if and only if 'cookie' matches
662 * the current transport 'connection cookie'. It ensures that we don't
663 * try to break the connection more than once when we need to retransmit
664 * a batch of RPC requests.
667 void xprt_conditional_disconnect(struct rpc_xprt
*xprt
, unsigned int cookie
)
669 /* Don't race with the test_bit() in xprt_clear_locked() */
670 spin_lock_bh(&xprt
->transport_lock
);
671 if (cookie
!= xprt
->connect_cookie
)
673 if (test_bit(XPRT_CLOSING
, &xprt
->state
))
675 set_bit(XPRT_CLOSE_WAIT
, &xprt
->state
);
676 /* Try to schedule an autoclose RPC call */
677 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
) == 0)
678 queue_work(xprtiod_workqueue
, &xprt
->task_cleanup
);
679 xprt_wake_pending_tasks(xprt
, -EAGAIN
);
681 spin_unlock_bh(&xprt
->transport_lock
);
685 xprt_has_timer(const struct rpc_xprt
*xprt
)
687 return xprt
->idle_timeout
!= 0;
691 xprt_schedule_autodisconnect(struct rpc_xprt
*xprt
)
692 __must_hold(&xprt
->transport_lock
)
694 if (list_empty(&xprt
->recv
) && xprt_has_timer(xprt
))
695 mod_timer(&xprt
->timer
, xprt
->last_used
+ xprt
->idle_timeout
);
699 xprt_init_autodisconnect(unsigned long data
)
701 struct rpc_xprt
*xprt
= (struct rpc_xprt
*)data
;
703 spin_lock(&xprt
->transport_lock
);
704 if (!list_empty(&xprt
->recv
))
706 /* Reset xprt->last_used to avoid connect/autodisconnect cycling */
707 xprt
->last_used
= jiffies
;
708 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
))
710 spin_unlock(&xprt
->transport_lock
);
711 queue_work(xprtiod_workqueue
, &xprt
->task_cleanup
);
714 spin_unlock(&xprt
->transport_lock
);
717 bool xprt_lock_connect(struct rpc_xprt
*xprt
,
718 struct rpc_task
*task
,
723 spin_lock_bh(&xprt
->transport_lock
);
724 if (!test_bit(XPRT_LOCKED
, &xprt
->state
))
726 if (xprt
->snd_task
!= task
)
728 xprt_task_clear_bytes_sent(task
);
729 xprt
->snd_task
= cookie
;
732 spin_unlock_bh(&xprt
->transport_lock
);
736 void xprt_unlock_connect(struct rpc_xprt
*xprt
, void *cookie
)
738 spin_lock_bh(&xprt
->transport_lock
);
739 if (xprt
->snd_task
!= cookie
)
741 if (!test_bit(XPRT_LOCKED
, &xprt
->state
))
743 xprt
->snd_task
=NULL
;
744 xprt
->ops
->release_xprt(xprt
, NULL
);
745 xprt_schedule_autodisconnect(xprt
);
747 spin_unlock_bh(&xprt
->transport_lock
);
748 wake_up_bit(&xprt
->state
, XPRT_LOCKED
);
752 * xprt_connect - schedule a transport connect operation
753 * @task: RPC task that is requesting the connect
756 void xprt_connect(struct rpc_task
*task
)
758 struct rpc_xprt
*xprt
= task
->tk_rqstp
->rq_xprt
;
760 dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task
->tk_pid
,
761 xprt
, (xprt_connected(xprt
) ? "is" : "is not"));
763 if (!xprt_bound(xprt
)) {
764 task
->tk_status
= -EAGAIN
;
767 if (!xprt_lock_write(xprt
, task
))
770 if (test_and_clear_bit(XPRT_CLOSE_WAIT
, &xprt
->state
))
771 xprt
->ops
->close(xprt
);
773 if (!xprt_connected(xprt
)) {
774 task
->tk_rqstp
->rq_bytes_sent
= 0;
775 task
->tk_timeout
= task
->tk_rqstp
->rq_timeout
;
776 task
->tk_rqstp
->rq_connect_cookie
= xprt
->connect_cookie
;
777 rpc_sleep_on(&xprt
->pending
, task
, xprt_connect_status
);
779 if (test_bit(XPRT_CLOSING
, &xprt
->state
))
781 if (xprt_test_and_set_connecting(xprt
))
783 xprt
->stat
.connect_start
= jiffies
;
784 xprt
->ops
->connect(xprt
, task
);
786 xprt_release_write(xprt
, task
);
789 static void xprt_connect_status(struct rpc_task
*task
)
791 struct rpc_xprt
*xprt
= task
->tk_rqstp
->rq_xprt
;
793 if (task
->tk_status
== 0) {
794 xprt
->stat
.connect_count
++;
795 xprt
->stat
.connect_time
+= (long)jiffies
- xprt
->stat
.connect_start
;
796 dprintk("RPC: %5u xprt_connect_status: connection established\n",
801 switch (task
->tk_status
) {
809 dprintk("RPC: %5u xprt_connect_status: retrying\n", task
->tk_pid
);
812 dprintk("RPC: %5u xprt_connect_status: connect attempt timed "
813 "out\n", task
->tk_pid
);
816 dprintk("RPC: %5u xprt_connect_status: error %d connecting to "
817 "server %s\n", task
->tk_pid
, -task
->tk_status
,
819 task
->tk_status
= -EIO
;
824 * xprt_lookup_rqst - find an RPC request corresponding to an XID
825 * @xprt: transport on which the original request was transmitted
826 * @xid: RPC XID of incoming reply
829 struct rpc_rqst
*xprt_lookup_rqst(struct rpc_xprt
*xprt
, __be32 xid
)
831 struct rpc_rqst
*entry
;
833 list_for_each_entry(entry
, &xprt
->recv
, rq_list
)
834 if (entry
->rq_xid
== xid
) {
835 trace_xprt_lookup_rqst(xprt
, xid
, 0);
839 dprintk("RPC: xprt_lookup_rqst did not find xid %08x\n",
841 trace_xprt_lookup_rqst(xprt
, xid
, -ENOENT
);
842 xprt
->stat
.bad_xids
++;
845 EXPORT_SYMBOL_GPL(xprt_lookup_rqst
);
847 static void xprt_update_rtt(struct rpc_task
*task
)
849 struct rpc_rqst
*req
= task
->tk_rqstp
;
850 struct rpc_rtt
*rtt
= task
->tk_client
->cl_rtt
;
851 unsigned int timer
= task
->tk_msg
.rpc_proc
->p_timer
;
852 long m
= usecs_to_jiffies(ktime_to_us(req
->rq_rtt
));
855 if (req
->rq_ntrans
== 1)
856 rpc_update_rtt(rtt
, timer
, m
);
857 rpc_set_timeo(rtt
, timer
, req
->rq_ntrans
- 1);
862 * xprt_complete_rqst - called when reply processing is complete
863 * @task: RPC request that recently completed
864 * @copied: actual number of bytes received from the transport
866 * Caller holds transport lock.
868 void xprt_complete_rqst(struct rpc_task
*task
, int copied
)
870 struct rpc_rqst
*req
= task
->tk_rqstp
;
871 struct rpc_xprt
*xprt
= req
->rq_xprt
;
873 dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
874 task
->tk_pid
, ntohl(req
->rq_xid
), copied
);
875 trace_xprt_complete_rqst(xprt
, req
->rq_xid
, copied
);
878 req
->rq_rtt
= ktime_sub(ktime_get(), req
->rq_xtime
);
879 if (xprt
->ops
->timer
!= NULL
)
880 xprt_update_rtt(task
);
882 list_del_init(&req
->rq_list
);
883 req
->rq_private_buf
.len
= copied
;
884 /* Ensure all writes are done before we update */
885 /* req->rq_reply_bytes_recvd */
887 req
->rq_reply_bytes_recvd
= copied
;
888 rpc_wake_up_queued_task(&xprt
->pending
, task
);
890 EXPORT_SYMBOL_GPL(xprt_complete_rqst
);
892 static void xprt_timer(struct rpc_task
*task
)
894 struct rpc_rqst
*req
= task
->tk_rqstp
;
895 struct rpc_xprt
*xprt
= req
->rq_xprt
;
897 if (task
->tk_status
!= -ETIMEDOUT
)
899 dprintk("RPC: %5u xprt_timer\n", task
->tk_pid
);
901 if (!req
->rq_reply_bytes_recvd
) {
902 if (xprt
->ops
->timer
)
903 xprt
->ops
->timer(xprt
, task
);
909 * xprt_prepare_transmit - reserve the transport before sending a request
910 * @task: RPC task about to send a request
913 bool xprt_prepare_transmit(struct rpc_task
*task
)
915 struct rpc_rqst
*req
= task
->tk_rqstp
;
916 struct rpc_xprt
*xprt
= req
->rq_xprt
;
919 dprintk("RPC: %5u xprt_prepare_transmit\n", task
->tk_pid
);
921 spin_lock_bh(&xprt
->transport_lock
);
922 if (!req
->rq_bytes_sent
) {
923 if (req
->rq_reply_bytes_recvd
) {
924 task
->tk_status
= req
->rq_reply_bytes_recvd
;
927 if ((task
->tk_flags
& RPC_TASK_NO_RETRANS_TIMEOUT
)
928 && xprt_connected(xprt
)
929 && req
->rq_connect_cookie
== xprt
->connect_cookie
) {
930 xprt
->ops
->set_retrans_timeout(task
);
931 rpc_sleep_on(&xprt
->pending
, task
, xprt_timer
);
935 if (!xprt
->ops
->reserve_xprt(xprt
, task
)) {
936 task
->tk_status
= -EAGAIN
;
941 spin_unlock_bh(&xprt
->transport_lock
);
945 void xprt_end_transmit(struct rpc_task
*task
)
947 xprt_release_write(task
->tk_rqstp
->rq_xprt
, task
);
951 * xprt_transmit - send an RPC request on a transport
952 * @task: controlling RPC task
954 * We have to copy the iovec because sendmsg fiddles with its contents.
956 void xprt_transmit(struct rpc_task
*task
)
958 struct rpc_rqst
*req
= task
->tk_rqstp
;
959 struct rpc_xprt
*xprt
= req
->rq_xprt
;
962 dprintk("RPC: %5u xprt_transmit(%u)\n", task
->tk_pid
, req
->rq_slen
);
964 if (!req
->rq_reply_bytes_recvd
) {
965 if (list_empty(&req
->rq_list
) && rpc_reply_expected(task
)) {
967 * Add to the list only if we're expecting a reply
969 spin_lock_bh(&xprt
->transport_lock
);
970 /* Update the softirq receive buffer */
971 memcpy(&req
->rq_private_buf
, &req
->rq_rcv_buf
,
972 sizeof(req
->rq_private_buf
));
973 /* Add request to the receive list */
974 list_add_tail(&req
->rq_list
, &xprt
->recv
);
975 spin_unlock_bh(&xprt
->transport_lock
);
976 xprt_reset_majortimeo(req
);
977 /* Turn off autodisconnect */
978 del_singleshot_timer_sync(&xprt
->timer
);
980 } else if (!req
->rq_bytes_sent
)
983 req
->rq_xtime
= ktime_get();
984 status
= xprt
->ops
->send_request(task
);
985 trace_xprt_transmit(xprt
, req
->rq_xid
, status
);
987 task
->tk_status
= status
;
990 xprt_inject_disconnect(xprt
);
992 dprintk("RPC: %5u xmit complete\n", task
->tk_pid
);
993 task
->tk_flags
|= RPC_TASK_SENT
;
994 spin_lock_bh(&xprt
->transport_lock
);
996 xprt
->ops
->set_retrans_timeout(task
);
998 numreqs
= atomic_read(&xprt
->num_reqs
);
999 if (numreqs
> xprt
->stat
.max_slots
)
1000 xprt
->stat
.max_slots
= numreqs
;
1002 xprt
->stat
.req_u
+= xprt
->stat
.sends
- xprt
->stat
.recvs
;
1003 xprt
->stat
.bklog_u
+= xprt
->backlog
.qlen
;
1004 xprt
->stat
.sending_u
+= xprt
->sending
.qlen
;
1005 xprt
->stat
.pending_u
+= xprt
->pending
.qlen
;
1007 /* Don't race with disconnect */
1008 if (!xprt_connected(xprt
))
1009 task
->tk_status
= -ENOTCONN
;
1012 * Sleep on the pending queue since
1013 * we're expecting a reply.
1015 if (!req
->rq_reply_bytes_recvd
&& rpc_reply_expected(task
))
1016 rpc_sleep_on(&xprt
->pending
, task
, xprt_timer
);
1017 req
->rq_connect_cookie
= xprt
->connect_cookie
;
1019 spin_unlock_bh(&xprt
->transport_lock
);
1022 static void xprt_add_backlog(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
1024 set_bit(XPRT_CONGESTED
, &xprt
->state
);
1025 rpc_sleep_on(&xprt
->backlog
, task
, NULL
);
1028 static void xprt_wake_up_backlog(struct rpc_xprt
*xprt
)
1030 if (rpc_wake_up_next(&xprt
->backlog
) == NULL
)
1031 clear_bit(XPRT_CONGESTED
, &xprt
->state
);
1034 static bool xprt_throttle_congested(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
1038 if (!test_bit(XPRT_CONGESTED
, &xprt
->state
))
1040 spin_lock(&xprt
->reserve_lock
);
1041 if (test_bit(XPRT_CONGESTED
, &xprt
->state
)) {
1042 rpc_sleep_on(&xprt
->backlog
, task
, NULL
);
1045 spin_unlock(&xprt
->reserve_lock
);
1050 static struct rpc_rqst
*xprt_dynamic_alloc_slot(struct rpc_xprt
*xprt
)
1052 struct rpc_rqst
*req
= ERR_PTR(-EAGAIN
);
1054 if (!atomic_add_unless(&xprt
->num_reqs
, 1, xprt
->max_reqs
))
1056 spin_unlock(&xprt
->reserve_lock
);
1057 req
= kzalloc(sizeof(struct rpc_rqst
), GFP_NOFS
);
1058 spin_lock(&xprt
->reserve_lock
);
1061 atomic_dec(&xprt
->num_reqs
);
1062 req
= ERR_PTR(-ENOMEM
);
1067 static bool xprt_dynamic_free_slot(struct rpc_xprt
*xprt
, struct rpc_rqst
*req
)
1069 if (atomic_add_unless(&xprt
->num_reqs
, -1, xprt
->min_reqs
)) {
1076 void xprt_alloc_slot(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
1078 struct rpc_rqst
*req
;
1080 spin_lock(&xprt
->reserve_lock
);
1081 if (!list_empty(&xprt
->free
)) {
1082 req
= list_entry(xprt
->free
.next
, struct rpc_rqst
, rq_list
);
1083 list_del(&req
->rq_list
);
1086 req
= xprt_dynamic_alloc_slot(xprt
);
1089 switch (PTR_ERR(req
)) {
1091 dprintk("RPC: dynamic allocation of request slot "
1092 "failed! Retrying\n");
1093 task
->tk_status
= -ENOMEM
;
1096 xprt_add_backlog(xprt
, task
);
1097 dprintk("RPC: waiting for request slot\n");
1099 task
->tk_status
= -EAGAIN
;
1101 spin_unlock(&xprt
->reserve_lock
);
1104 task
->tk_status
= 0;
1105 task
->tk_rqstp
= req
;
1106 xprt_request_init(task
, xprt
);
1107 spin_unlock(&xprt
->reserve_lock
);
1109 EXPORT_SYMBOL_GPL(xprt_alloc_slot
);
1111 void xprt_lock_and_alloc_slot(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
1113 /* Note: grabbing the xprt_lock_write() ensures that we throttle
1114 * new slot allocation if the transport is congested (i.e. when
1115 * reconnecting a stream transport or when out of socket write
1118 if (xprt_lock_write(xprt
, task
)) {
1119 xprt_alloc_slot(xprt
, task
);
1120 xprt_release_write(xprt
, task
);
1123 EXPORT_SYMBOL_GPL(xprt_lock_and_alloc_slot
);
1125 static void xprt_free_slot(struct rpc_xprt
*xprt
, struct rpc_rqst
*req
)
1127 spin_lock(&xprt
->reserve_lock
);
1128 if (!xprt_dynamic_free_slot(xprt
, req
)) {
1129 memset(req
, 0, sizeof(*req
)); /* mark unused */
1130 list_add(&req
->rq_list
, &xprt
->free
);
1132 xprt_wake_up_backlog(xprt
);
1133 spin_unlock(&xprt
->reserve_lock
);
1136 static void xprt_free_all_slots(struct rpc_xprt
*xprt
)
1138 struct rpc_rqst
*req
;
1139 while (!list_empty(&xprt
->free
)) {
1140 req
= list_first_entry(&xprt
->free
, struct rpc_rqst
, rq_list
);
1141 list_del(&req
->rq_list
);
1146 struct rpc_xprt
*xprt_alloc(struct net
*net
, size_t size
,
1147 unsigned int num_prealloc
,
1148 unsigned int max_alloc
)
1150 struct rpc_xprt
*xprt
;
1151 struct rpc_rqst
*req
;
1154 xprt
= kzalloc(size
, GFP_KERNEL
);
1158 xprt_init(xprt
, net
);
1160 for (i
= 0; i
< num_prealloc
; i
++) {
1161 req
= kzalloc(sizeof(struct rpc_rqst
), GFP_KERNEL
);
1164 list_add(&req
->rq_list
, &xprt
->free
);
1166 if (max_alloc
> num_prealloc
)
1167 xprt
->max_reqs
= max_alloc
;
1169 xprt
->max_reqs
= num_prealloc
;
1170 xprt
->min_reqs
= num_prealloc
;
1171 atomic_set(&xprt
->num_reqs
, num_prealloc
);
1180 EXPORT_SYMBOL_GPL(xprt_alloc
);
1182 void xprt_free(struct rpc_xprt
*xprt
)
1184 put_net(xprt
->xprt_net
);
1185 xprt_free_all_slots(xprt
);
1186 kfree_rcu(xprt
, rcu
);
1188 EXPORT_SYMBOL_GPL(xprt_free
);
1191 * xprt_reserve - allocate an RPC request slot
1192 * @task: RPC task requesting a slot allocation
1194 * If the transport is marked as being congested, or if no more
1195 * slots are available, place the task on the transport's
1198 void xprt_reserve(struct rpc_task
*task
)
1200 struct rpc_xprt
*xprt
= task
->tk_xprt
;
1202 task
->tk_status
= 0;
1203 if (task
->tk_rqstp
!= NULL
)
1206 task
->tk_timeout
= 0;
1207 task
->tk_status
= -EAGAIN
;
1208 if (!xprt_throttle_congested(xprt
, task
))
1209 xprt
->ops
->alloc_slot(xprt
, task
);
1213 * xprt_retry_reserve - allocate an RPC request slot
1214 * @task: RPC task requesting a slot allocation
1216 * If no more slots are available, place the task on the transport's
1218 * Note that the only difference with xprt_reserve is that we now
1219 * ignore the value of the XPRT_CONGESTED flag.
1221 void xprt_retry_reserve(struct rpc_task
*task
)
1223 struct rpc_xprt
*xprt
= task
->tk_xprt
;
1225 task
->tk_status
= 0;
1226 if (task
->tk_rqstp
!= NULL
)
1229 task
->tk_timeout
= 0;
1230 task
->tk_status
= -EAGAIN
;
1231 xprt
->ops
->alloc_slot(xprt
, task
);
1234 static inline __be32
xprt_alloc_xid(struct rpc_xprt
*xprt
)
1236 return (__force __be32
)xprt
->xid
++;
1239 static inline void xprt_init_xid(struct rpc_xprt
*xprt
)
1241 xprt
->xid
= prandom_u32();
1244 static void xprt_request_init(struct rpc_task
*task
, struct rpc_xprt
*xprt
)
1246 struct rpc_rqst
*req
= task
->tk_rqstp
;
1248 INIT_LIST_HEAD(&req
->rq_list
);
1249 req
->rq_timeout
= task
->tk_client
->cl_timeout
->to_initval
;
1250 req
->rq_task
= task
;
1251 req
->rq_xprt
= xprt
;
1252 req
->rq_buffer
= NULL
;
1253 req
->rq_xid
= xprt_alloc_xid(xprt
);
1254 req
->rq_connect_cookie
= xprt
->connect_cookie
- 1;
1255 req
->rq_bytes_sent
= 0;
1256 req
->rq_snd_buf
.len
= 0;
1257 req
->rq_snd_buf
.buflen
= 0;
1258 req
->rq_rcv_buf
.len
= 0;
1259 req
->rq_rcv_buf
.buflen
= 0;
1260 req
->rq_release_snd_buf
= NULL
;
1261 xprt_reset_majortimeo(req
);
1262 dprintk("RPC: %5u reserved req %p xid %08x\n", task
->tk_pid
,
1263 req
, ntohl(req
->rq_xid
));
1267 * xprt_release - release an RPC request slot
1268 * @task: task which is finished with the slot
1271 void xprt_release(struct rpc_task
*task
)
1273 struct rpc_xprt
*xprt
;
1274 struct rpc_rqst
*req
= task
->tk_rqstp
;
1277 if (task
->tk_client
) {
1278 xprt
= task
->tk_xprt
;
1279 if (xprt
->snd_task
== task
)
1280 xprt_release_write(xprt
, task
);
1285 xprt
= req
->rq_xprt
;
1286 if (task
->tk_ops
->rpc_count_stats
!= NULL
)
1287 task
->tk_ops
->rpc_count_stats(task
, task
->tk_calldata
);
1288 else if (task
->tk_client
)
1289 rpc_count_iostats(task
, task
->tk_client
->cl_metrics
);
1290 spin_lock_bh(&xprt
->transport_lock
);
1291 xprt
->ops
->release_xprt(xprt
, task
);
1292 if (xprt
->ops
->release_request
)
1293 xprt
->ops
->release_request(task
);
1294 if (!list_empty(&req
->rq_list
))
1295 list_del(&req
->rq_list
);
1296 xprt
->last_used
= jiffies
;
1297 xprt_schedule_autodisconnect(xprt
);
1298 spin_unlock_bh(&xprt
->transport_lock
);
1300 xprt
->ops
->buf_free(task
);
1301 xprt_inject_disconnect(xprt
);
1302 if (req
->rq_cred
!= NULL
)
1303 put_rpccred(req
->rq_cred
);
1304 task
->tk_rqstp
= NULL
;
1305 if (req
->rq_release_snd_buf
)
1306 req
->rq_release_snd_buf(req
);
1308 dprintk("RPC: %5u release request %p\n", task
->tk_pid
, req
);
1309 if (likely(!bc_prealloc(req
)))
1310 xprt_free_slot(xprt
, req
);
1312 xprt_free_bc_request(req
);
1315 static void xprt_init(struct rpc_xprt
*xprt
, struct net
*net
)
1317 kref_init(&xprt
->kref
);
1319 spin_lock_init(&xprt
->transport_lock
);
1320 spin_lock_init(&xprt
->reserve_lock
);
1322 INIT_LIST_HEAD(&xprt
->free
);
1323 INIT_LIST_HEAD(&xprt
->recv
);
1324 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1325 spin_lock_init(&xprt
->bc_pa_lock
);
1326 INIT_LIST_HEAD(&xprt
->bc_pa_list
);
1327 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1328 INIT_LIST_HEAD(&xprt
->xprt_switch
);
1330 xprt
->last_used
= jiffies
;
1331 xprt
->cwnd
= RPC_INITCWND
;
1332 xprt
->bind_index
= 0;
1334 rpc_init_wait_queue(&xprt
->binding
, "xprt_binding");
1335 rpc_init_wait_queue(&xprt
->pending
, "xprt_pending");
1336 rpc_init_priority_wait_queue(&xprt
->sending
, "xprt_sending");
1337 rpc_init_priority_wait_queue(&xprt
->backlog
, "xprt_backlog");
1339 xprt_init_xid(xprt
);
1341 xprt
->xprt_net
= get_net(net
);
1345 * xprt_create_transport - create an RPC transport
1346 * @args: rpc transport creation arguments
1349 struct rpc_xprt
*xprt_create_transport(struct xprt_create
*args
)
1351 struct rpc_xprt
*xprt
;
1352 struct xprt_class
*t
;
1354 spin_lock(&xprt_list_lock
);
1355 list_for_each_entry(t
, &xprt_list
, list
) {
1356 if (t
->ident
== args
->ident
) {
1357 spin_unlock(&xprt_list_lock
);
1361 spin_unlock(&xprt_list_lock
);
1362 dprintk("RPC: transport (%d) not supported\n", args
->ident
);
1363 return ERR_PTR(-EIO
);
1366 xprt
= t
->setup(args
);
1368 dprintk("RPC: xprt_create_transport: failed, %ld\n",
1372 if (args
->flags
& XPRT_CREATE_NO_IDLE_TIMEOUT
)
1373 xprt
->idle_timeout
= 0;
1374 INIT_WORK(&xprt
->task_cleanup
, xprt_autoclose
);
1375 if (xprt_has_timer(xprt
))
1376 setup_timer(&xprt
->timer
, xprt_init_autodisconnect
,
1377 (unsigned long)xprt
);
1379 init_timer(&xprt
->timer
);
1381 if (strlen(args
->servername
) > RPC_MAXNETNAMELEN
) {
1383 return ERR_PTR(-EINVAL
);
1385 xprt
->servername
= kstrdup(args
->servername
, GFP_KERNEL
);
1386 if (xprt
->servername
== NULL
) {
1388 return ERR_PTR(-ENOMEM
);
1391 rpc_xprt_debugfs_register(xprt
);
1393 dprintk("RPC: created transport %p with %u slots\n", xprt
,
1400 * xprt_destroy - destroy an RPC transport, killing off all requests.
1401 * @xprt: transport to destroy
1404 static void xprt_destroy(struct rpc_xprt
*xprt
)
1406 dprintk("RPC: destroying transport %p\n", xprt
);
1408 /* Exclude transport connect/disconnect handlers */
1409 wait_on_bit_lock(&xprt
->state
, XPRT_LOCKED
, TASK_UNINTERRUPTIBLE
);
1411 del_timer_sync(&xprt
->timer
);
1413 rpc_xprt_debugfs_unregister(xprt
);
1414 rpc_destroy_wait_queue(&xprt
->binding
);
1415 rpc_destroy_wait_queue(&xprt
->pending
);
1416 rpc_destroy_wait_queue(&xprt
->sending
);
1417 rpc_destroy_wait_queue(&xprt
->backlog
);
1418 cancel_work_sync(&xprt
->task_cleanup
);
1419 kfree(xprt
->servername
);
1421 * Tear down transport state and free the rpc_xprt
1423 xprt
->ops
->destroy(xprt
);
1426 static void xprt_destroy_kref(struct kref
*kref
)
1428 xprt_destroy(container_of(kref
, struct rpc_xprt
, kref
));
1432 * xprt_get - return a reference to an RPC transport.
1433 * @xprt: pointer to the transport
1436 struct rpc_xprt
*xprt_get(struct rpc_xprt
*xprt
)
1438 if (xprt
!= NULL
&& kref_get_unless_zero(&xprt
->kref
))
1442 EXPORT_SYMBOL_GPL(xprt_get
);
1445 * xprt_put - release a reference to an RPC transport.
1446 * @xprt: pointer to the transport
1449 void xprt_put(struct rpc_xprt
*xprt
)
1452 kref_put(&xprt
->kref
, xprt_destroy_kref
);
1454 EXPORT_SYMBOL_GPL(xprt_put
);