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>
59 # define RPCDBG_FACILITY RPCDBG_XPRT
65 static void xprt_init(struct rpc_xprt
*xprt
, struct net
*net
);
66 static void xprt_request_init(struct rpc_task
*, struct rpc_xprt
*);
67 static void xprt_connect_status(struct rpc_task
*task
);
68 static int __xprt_get_cong(struct rpc_xprt
*, struct rpc_task
*);
69 static void xprt_destroy(struct rpc_xprt
*xprt
);
71 static DEFINE_SPINLOCK(xprt_list_lock
);
72 static LIST_HEAD(xprt_list
);
75 * The transport code maintains an estimate on the maximum number of out-
76 * standing RPC requests, using a smoothed version of the congestion
77 * avoidance implemented in 44BSD. This is basically the Van Jacobson
78 * congestion algorithm: If a retransmit occurs, the congestion window is
79 * halved; otherwise, it is incremented by 1/cwnd when
81 * - a reply is received and
82 * - a full number of requests are outstanding and
83 * - the congestion window hasn't been updated recently.
85 #define RPC_CWNDSHIFT (8U)
86 #define RPC_CWNDSCALE (1U << RPC_CWNDSHIFT)
87 #define RPC_INITCWND RPC_CWNDSCALE
88 #define RPC_MAXCWND(xprt) ((xprt)->max_reqs << RPC_CWNDSHIFT)
90 #define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
93 * xprt_register_transport - register a transport implementation
94 * @transport: transport to register
96 * If a transport implementation is loaded as a kernel module, it can
97 * call this interface to make itself known to the RPC client.
100 * 0: transport successfully registered
101 * -EEXIST: transport already registered
102 * -EINVAL: transport module being unloaded
104 int xprt_register_transport(struct xprt_class
*transport
)
106 struct xprt_class
*t
;
110 spin_lock(&xprt_list_lock
);
111 list_for_each_entry(t
, &xprt_list
, list
) {
112 /* don't register the same transport class twice */
113 if (t
->ident
== transport
->ident
)
117 list_add_tail(&transport
->list
, &xprt_list
);
118 printk(KERN_INFO
"RPC: Registered %s transport module.\n",
123 spin_unlock(&xprt_list_lock
);
126 EXPORT_SYMBOL_GPL(xprt_register_transport
);
129 * xprt_unregister_transport - unregister a transport implementation
130 * @transport: transport to unregister
133 * 0: transport successfully unregistered
134 * -ENOENT: transport never registered
136 int xprt_unregister_transport(struct xprt_class
*transport
)
138 struct xprt_class
*t
;
142 spin_lock(&xprt_list_lock
);
143 list_for_each_entry(t
, &xprt_list
, list
) {
144 if (t
== transport
) {
146 "RPC: Unregistered %s transport module.\n",
148 list_del_init(&transport
->list
);
155 spin_unlock(&xprt_list_lock
);
158 EXPORT_SYMBOL_GPL(xprt_unregister_transport
);
161 * xprt_load_transport - load a transport implementation
162 * @transport_name: transport to load
165 * 0: transport successfully loaded
166 * -ENOENT: transport module not available
168 int xprt_load_transport(const char *transport_name
)
170 struct xprt_class
*t
;
174 spin_lock(&xprt_list_lock
);
175 list_for_each_entry(t
, &xprt_list
, list
) {
176 if (strcmp(t
->name
, transport_name
) == 0) {
177 spin_unlock(&xprt_list_lock
);
181 spin_unlock(&xprt_list_lock
);
182 result
= request_module("xprt%s", transport_name
);
186 EXPORT_SYMBOL_GPL(xprt_load_transport
);
189 * xprt_reserve_xprt - serialize write access to transports
190 * @task: task that is requesting access to the transport
191 * @xprt: pointer to the target transport
193 * This prevents mixing the payload of separate requests, and prevents
194 * transport connects from colliding with writes. No congestion control
197 int xprt_reserve_xprt(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
199 struct rpc_rqst
*req
= task
->tk_rqstp
;
202 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
)) {
203 if (task
== xprt
->snd_task
)
207 xprt
->snd_task
= task
;
209 req
->rq_bytes_sent
= 0;
216 dprintk("RPC: %5u failed to lock transport %p\n",
218 task
->tk_timeout
= 0;
219 task
->tk_status
= -EAGAIN
;
221 priority
= RPC_PRIORITY_LOW
;
222 else if (!req
->rq_ntrans
)
223 priority
= RPC_PRIORITY_NORMAL
;
225 priority
= RPC_PRIORITY_HIGH
;
226 rpc_sleep_on_priority(&xprt
->sending
, task
, NULL
, priority
);
229 EXPORT_SYMBOL_GPL(xprt_reserve_xprt
);
231 static void xprt_clear_locked(struct rpc_xprt
*xprt
)
233 xprt
->snd_task
= NULL
;
234 if (!test_bit(XPRT_CLOSE_WAIT
, &xprt
->state
) || xprt
->shutdown
) {
235 smp_mb__before_clear_bit();
236 clear_bit(XPRT_LOCKED
, &xprt
->state
);
237 smp_mb__after_clear_bit();
239 queue_work(rpciod_workqueue
, &xprt
->task_cleanup
);
243 * xprt_reserve_xprt_cong - serialize write access to transports
244 * @task: task that is requesting access to the transport
246 * Same as xprt_reserve_xprt, but Van Jacobson congestion control is
247 * integrated into the decision of whether a request is allowed to be
248 * woken up and given access to the transport.
250 int xprt_reserve_xprt_cong(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
252 struct rpc_rqst
*req
= task
->tk_rqstp
;
255 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
)) {
256 if (task
== xprt
->snd_task
)
261 xprt
->snd_task
= task
;
264 if (__xprt_get_cong(xprt
, task
)) {
265 xprt
->snd_task
= task
;
266 req
->rq_bytes_sent
= 0;
270 xprt_clear_locked(xprt
);
272 dprintk("RPC: %5u failed to lock transport %p\n", task
->tk_pid
, xprt
);
273 task
->tk_timeout
= 0;
274 task
->tk_status
= -EAGAIN
;
276 priority
= RPC_PRIORITY_LOW
;
277 else if (!req
->rq_ntrans
)
278 priority
= RPC_PRIORITY_NORMAL
;
280 priority
= RPC_PRIORITY_HIGH
;
281 rpc_sleep_on_priority(&xprt
->sending
, task
, NULL
, priority
);
284 EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong
);
286 static inline int xprt_lock_write(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
290 spin_lock_bh(&xprt
->transport_lock
);
291 retval
= xprt
->ops
->reserve_xprt(xprt
, task
);
292 spin_unlock_bh(&xprt
->transport_lock
);
296 static bool __xprt_lock_write_func(struct rpc_task
*task
, void *data
)
298 struct rpc_xprt
*xprt
= data
;
299 struct rpc_rqst
*req
;
301 req
= task
->tk_rqstp
;
302 xprt
->snd_task
= task
;
304 req
->rq_bytes_sent
= 0;
310 static void __xprt_lock_write_next(struct rpc_xprt
*xprt
)
312 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
))
315 if (rpc_wake_up_first(&xprt
->sending
, __xprt_lock_write_func
, xprt
))
317 xprt_clear_locked(xprt
);
320 static bool __xprt_lock_write_cong_func(struct rpc_task
*task
, void *data
)
322 struct rpc_xprt
*xprt
= data
;
323 struct rpc_rqst
*req
;
325 req
= task
->tk_rqstp
;
327 xprt
->snd_task
= task
;
330 if (__xprt_get_cong(xprt
, task
)) {
331 xprt
->snd_task
= task
;
332 req
->rq_bytes_sent
= 0;
339 static void __xprt_lock_write_next_cong(struct rpc_xprt
*xprt
)
341 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
))
343 if (RPCXPRT_CONGESTED(xprt
))
345 if (rpc_wake_up_first(&xprt
->sending
, __xprt_lock_write_cong_func
, xprt
))
348 xprt_clear_locked(xprt
);
352 * xprt_release_xprt - allow other requests to use a transport
353 * @xprt: transport with other tasks potentially waiting
354 * @task: task that is releasing access to the transport
356 * Note that "task" can be NULL. No congestion control is provided.
358 void xprt_release_xprt(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
360 if (xprt
->snd_task
== task
) {
361 xprt_clear_locked(xprt
);
362 __xprt_lock_write_next(xprt
);
365 EXPORT_SYMBOL_GPL(xprt_release_xprt
);
368 * xprt_release_xprt_cong - allow other requests to use a transport
369 * @xprt: transport with other tasks potentially waiting
370 * @task: task that is releasing access to the transport
372 * Note that "task" can be NULL. Another task is awoken to use the
373 * transport if the transport's congestion window allows it.
375 void xprt_release_xprt_cong(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
377 if (xprt
->snd_task
== task
) {
378 xprt_clear_locked(xprt
);
379 __xprt_lock_write_next_cong(xprt
);
382 EXPORT_SYMBOL_GPL(xprt_release_xprt_cong
);
384 static inline void xprt_release_write(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
386 spin_lock_bh(&xprt
->transport_lock
);
387 xprt
->ops
->release_xprt(xprt
, task
);
388 spin_unlock_bh(&xprt
->transport_lock
);
392 * Van Jacobson congestion avoidance. Check if the congestion window
393 * overflowed. Put the task to sleep if this is the case.
396 __xprt_get_cong(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
398 struct rpc_rqst
*req
= task
->tk_rqstp
;
402 dprintk("RPC: %5u xprt_cwnd_limited cong = %lu cwnd = %lu\n",
403 task
->tk_pid
, xprt
->cong
, xprt
->cwnd
);
404 if (RPCXPRT_CONGESTED(xprt
))
407 xprt
->cong
+= RPC_CWNDSCALE
;
412 * Adjust the congestion window, and wake up the next task
413 * that has been sleeping due to congestion
416 __xprt_put_cong(struct rpc_xprt
*xprt
, struct rpc_rqst
*req
)
421 xprt
->cong
-= RPC_CWNDSCALE
;
422 __xprt_lock_write_next_cong(xprt
);
426 * xprt_release_rqst_cong - housekeeping when request is complete
427 * @task: RPC request that recently completed
429 * Useful for transports that require congestion control.
431 void xprt_release_rqst_cong(struct rpc_task
*task
)
433 __xprt_put_cong(task
->tk_xprt
, task
->tk_rqstp
);
435 EXPORT_SYMBOL_GPL(xprt_release_rqst_cong
);
438 * xprt_adjust_cwnd - adjust transport congestion window
439 * @task: recently completed RPC request used to adjust window
440 * @result: result code of completed RPC request
442 * We use a time-smoothed congestion estimator to avoid heavy oscillation.
444 void xprt_adjust_cwnd(struct rpc_task
*task
, int result
)
446 struct rpc_rqst
*req
= task
->tk_rqstp
;
447 struct rpc_xprt
*xprt
= task
->tk_xprt
;
448 unsigned long cwnd
= xprt
->cwnd
;
450 if (result
>= 0 && cwnd
<= xprt
->cong
) {
451 /* The (cwnd >> 1) term makes sure
452 * the result gets rounded properly. */
453 cwnd
+= (RPC_CWNDSCALE
* RPC_CWNDSCALE
+ (cwnd
>> 1)) / cwnd
;
454 if (cwnd
> RPC_MAXCWND(xprt
))
455 cwnd
= RPC_MAXCWND(xprt
);
456 __xprt_lock_write_next_cong(xprt
);
457 } else if (result
== -ETIMEDOUT
) {
459 if (cwnd
< RPC_CWNDSCALE
)
460 cwnd
= RPC_CWNDSCALE
;
462 dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n",
463 xprt
->cong
, xprt
->cwnd
, cwnd
);
465 __xprt_put_cong(xprt
, req
);
467 EXPORT_SYMBOL_GPL(xprt_adjust_cwnd
);
470 * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue
471 * @xprt: transport with waiting tasks
472 * @status: result code to plant in each task before waking it
475 void xprt_wake_pending_tasks(struct rpc_xprt
*xprt
, int status
)
478 rpc_wake_up_status(&xprt
->pending
, status
);
480 rpc_wake_up(&xprt
->pending
);
482 EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks
);
485 * xprt_wait_for_buffer_space - wait for transport output buffer to clear
486 * @task: task to be put to sleep
487 * @action: function pointer to be executed after wait
489 void xprt_wait_for_buffer_space(struct rpc_task
*task
, rpc_action action
)
491 struct rpc_rqst
*req
= task
->tk_rqstp
;
492 struct rpc_xprt
*xprt
= req
->rq_xprt
;
494 task
->tk_timeout
= req
->rq_timeout
;
495 rpc_sleep_on(&xprt
->pending
, task
, action
);
497 EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space
);
500 * xprt_write_space - wake the task waiting for transport output buffer space
501 * @xprt: transport with waiting tasks
503 * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
505 void xprt_write_space(struct rpc_xprt
*xprt
)
507 if (unlikely(xprt
->shutdown
))
510 spin_lock_bh(&xprt
->transport_lock
);
511 if (xprt
->snd_task
) {
512 dprintk("RPC: write space: waking waiting task on "
514 rpc_wake_up_queued_task(&xprt
->pending
, xprt
->snd_task
);
516 spin_unlock_bh(&xprt
->transport_lock
);
518 EXPORT_SYMBOL_GPL(xprt_write_space
);
521 * xprt_set_retrans_timeout_def - set a request's retransmit timeout
522 * @task: task whose timeout is to be set
524 * Set a request's retransmit timeout based on the transport's
525 * default timeout parameters. Used by transports that don't adjust
526 * the retransmit timeout based on round-trip time estimation.
528 void xprt_set_retrans_timeout_def(struct rpc_task
*task
)
530 task
->tk_timeout
= task
->tk_rqstp
->rq_timeout
;
532 EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_def
);
535 * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout
536 * @task: task whose timeout is to be set
538 * Set a request's retransmit timeout using the RTT estimator.
540 void xprt_set_retrans_timeout_rtt(struct rpc_task
*task
)
542 int timer
= task
->tk_msg
.rpc_proc
->p_timer
;
543 struct rpc_clnt
*clnt
= task
->tk_client
;
544 struct rpc_rtt
*rtt
= clnt
->cl_rtt
;
545 struct rpc_rqst
*req
= task
->tk_rqstp
;
546 unsigned long max_timeout
= clnt
->cl_timeout
->to_maxval
;
548 task
->tk_timeout
= rpc_calc_rto(rtt
, timer
);
549 task
->tk_timeout
<<= rpc_ntimeo(rtt
, timer
) + req
->rq_retries
;
550 if (task
->tk_timeout
> max_timeout
|| task
->tk_timeout
== 0)
551 task
->tk_timeout
= max_timeout
;
553 EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_rtt
);
555 static void xprt_reset_majortimeo(struct rpc_rqst
*req
)
557 const struct rpc_timeout
*to
= req
->rq_task
->tk_client
->cl_timeout
;
559 req
->rq_majortimeo
= req
->rq_timeout
;
560 if (to
->to_exponential
)
561 req
->rq_majortimeo
<<= to
->to_retries
;
563 req
->rq_majortimeo
+= to
->to_increment
* to
->to_retries
;
564 if (req
->rq_majortimeo
> to
->to_maxval
|| req
->rq_majortimeo
== 0)
565 req
->rq_majortimeo
= to
->to_maxval
;
566 req
->rq_majortimeo
+= jiffies
;
570 * xprt_adjust_timeout - adjust timeout values for next retransmit
571 * @req: RPC request containing parameters to use for the adjustment
574 int xprt_adjust_timeout(struct rpc_rqst
*req
)
576 struct rpc_xprt
*xprt
= req
->rq_xprt
;
577 const struct rpc_timeout
*to
= req
->rq_task
->tk_client
->cl_timeout
;
580 if (time_before(jiffies
, req
->rq_majortimeo
)) {
581 if (to
->to_exponential
)
582 req
->rq_timeout
<<= 1;
584 req
->rq_timeout
+= to
->to_increment
;
585 if (to
->to_maxval
&& req
->rq_timeout
>= to
->to_maxval
)
586 req
->rq_timeout
= to
->to_maxval
;
589 req
->rq_timeout
= to
->to_initval
;
591 xprt_reset_majortimeo(req
);
592 /* Reset the RTT counters == "slow start" */
593 spin_lock_bh(&xprt
->transport_lock
);
594 rpc_init_rtt(req
->rq_task
->tk_client
->cl_rtt
, to
->to_initval
);
595 spin_unlock_bh(&xprt
->transport_lock
);
599 if (req
->rq_timeout
== 0) {
600 printk(KERN_WARNING
"xprt_adjust_timeout: rq_timeout = 0!\n");
601 req
->rq_timeout
= 5 * HZ
;
606 static void xprt_autoclose(struct work_struct
*work
)
608 struct rpc_xprt
*xprt
=
609 container_of(work
, struct rpc_xprt
, task_cleanup
);
611 xprt
->ops
->close(xprt
);
612 clear_bit(XPRT_CLOSE_WAIT
, &xprt
->state
);
613 xprt_release_write(xprt
, NULL
);
617 * xprt_disconnect_done - mark a transport as disconnected
618 * @xprt: transport to flag for disconnect
621 void xprt_disconnect_done(struct rpc_xprt
*xprt
)
623 dprintk("RPC: disconnected transport %p\n", xprt
);
624 spin_lock_bh(&xprt
->transport_lock
);
625 xprt_clear_connected(xprt
);
626 xprt_wake_pending_tasks(xprt
, -EAGAIN
);
627 spin_unlock_bh(&xprt
->transport_lock
);
629 EXPORT_SYMBOL_GPL(xprt_disconnect_done
);
632 * xprt_force_disconnect - force a transport to disconnect
633 * @xprt: transport to disconnect
636 void xprt_force_disconnect(struct rpc_xprt
*xprt
)
638 /* Don't race with the test_bit() in xprt_clear_locked() */
639 spin_lock_bh(&xprt
->transport_lock
);
640 set_bit(XPRT_CLOSE_WAIT
, &xprt
->state
);
641 /* Try to schedule an autoclose RPC call */
642 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
) == 0)
643 queue_work(rpciod_workqueue
, &xprt
->task_cleanup
);
644 xprt_wake_pending_tasks(xprt
, -EAGAIN
);
645 spin_unlock_bh(&xprt
->transport_lock
);
649 * xprt_conditional_disconnect - force a transport to disconnect
650 * @xprt: transport to disconnect
651 * @cookie: 'connection cookie'
653 * This attempts to break the connection if and only if 'cookie' matches
654 * the current transport 'connection cookie'. It ensures that we don't
655 * try to break the connection more than once when we need to retransmit
656 * a batch of RPC requests.
659 void xprt_conditional_disconnect(struct rpc_xprt
*xprt
, unsigned int cookie
)
661 /* Don't race with the test_bit() in xprt_clear_locked() */
662 spin_lock_bh(&xprt
->transport_lock
);
663 if (cookie
!= xprt
->connect_cookie
)
665 if (test_bit(XPRT_CLOSING
, &xprt
->state
) || !xprt_connected(xprt
))
667 set_bit(XPRT_CLOSE_WAIT
, &xprt
->state
);
668 /* Try to schedule an autoclose RPC call */
669 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
) == 0)
670 queue_work(rpciod_workqueue
, &xprt
->task_cleanup
);
671 xprt_wake_pending_tasks(xprt
, -EAGAIN
);
673 spin_unlock_bh(&xprt
->transport_lock
);
677 xprt_init_autodisconnect(unsigned long data
)
679 struct rpc_xprt
*xprt
= (struct rpc_xprt
*)data
;
681 spin_lock(&xprt
->transport_lock
);
682 if (!list_empty(&xprt
->recv
) || xprt
->shutdown
)
684 if (test_and_set_bit(XPRT_LOCKED
, &xprt
->state
))
686 spin_unlock(&xprt
->transport_lock
);
687 set_bit(XPRT_CONNECTION_CLOSE
, &xprt
->state
);
688 queue_work(rpciod_workqueue
, &xprt
->task_cleanup
);
691 spin_unlock(&xprt
->transport_lock
);
695 * xprt_connect - schedule a transport connect operation
696 * @task: RPC task that is requesting the connect
699 void xprt_connect(struct rpc_task
*task
)
701 struct rpc_xprt
*xprt
= task
->tk_xprt
;
703 dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task
->tk_pid
,
704 xprt
, (xprt_connected(xprt
) ? "is" : "is not"));
706 if (!xprt_bound(xprt
)) {
707 task
->tk_status
= -EAGAIN
;
710 if (!xprt_lock_write(xprt
, task
))
713 if (test_and_clear_bit(XPRT_CLOSE_WAIT
, &xprt
->state
))
714 xprt
->ops
->close(xprt
);
716 if (xprt_connected(xprt
))
717 xprt_release_write(xprt
, task
);
719 task
->tk_rqstp
->rq_bytes_sent
= 0;
720 task
->tk_timeout
= task
->tk_rqstp
->rq_timeout
;
721 rpc_sleep_on(&xprt
->pending
, task
, xprt_connect_status
);
723 if (test_bit(XPRT_CLOSING
, &xprt
->state
))
725 if (xprt_test_and_set_connecting(xprt
))
727 xprt
->stat
.connect_start
= jiffies
;
728 xprt
->ops
->connect(task
);
732 static void xprt_connect_status(struct rpc_task
*task
)
734 struct rpc_xprt
*xprt
= task
->tk_xprt
;
736 if (task
->tk_status
== 0) {
737 xprt
->stat
.connect_count
++;
738 xprt
->stat
.connect_time
+= (long)jiffies
- xprt
->stat
.connect_start
;
739 dprintk("RPC: %5u xprt_connect_status: connection established\n",
744 switch (task
->tk_status
) {
746 dprintk("RPC: %5u xprt_connect_status: retrying\n", task
->tk_pid
);
749 dprintk("RPC: %5u xprt_connect_status: connect attempt timed "
750 "out\n", task
->tk_pid
);
753 dprintk("RPC: %5u xprt_connect_status: error %d connecting to "
754 "server %s\n", task
->tk_pid
, -task
->tk_status
,
756 xprt_release_write(xprt
, task
);
757 task
->tk_status
= -EIO
;
762 * xprt_lookup_rqst - find an RPC request corresponding to an XID
763 * @xprt: transport on which the original request was transmitted
764 * @xid: RPC XID of incoming reply
767 struct rpc_rqst
*xprt_lookup_rqst(struct rpc_xprt
*xprt
, __be32 xid
)
769 struct rpc_rqst
*entry
;
771 list_for_each_entry(entry
, &xprt
->recv
, rq_list
)
772 if (entry
->rq_xid
== xid
)
775 dprintk("RPC: xprt_lookup_rqst did not find xid %08x\n",
777 xprt
->stat
.bad_xids
++;
780 EXPORT_SYMBOL_GPL(xprt_lookup_rqst
);
782 static void xprt_update_rtt(struct rpc_task
*task
)
784 struct rpc_rqst
*req
= task
->tk_rqstp
;
785 struct rpc_rtt
*rtt
= task
->tk_client
->cl_rtt
;
786 unsigned int timer
= task
->tk_msg
.rpc_proc
->p_timer
;
787 long m
= usecs_to_jiffies(ktime_to_us(req
->rq_rtt
));
790 if (req
->rq_ntrans
== 1)
791 rpc_update_rtt(rtt
, timer
, m
);
792 rpc_set_timeo(rtt
, timer
, req
->rq_ntrans
- 1);
797 * xprt_complete_rqst - called when reply processing is complete
798 * @task: RPC request that recently completed
799 * @copied: actual number of bytes received from the transport
801 * Caller holds transport lock.
803 void xprt_complete_rqst(struct rpc_task
*task
, int copied
)
805 struct rpc_rqst
*req
= task
->tk_rqstp
;
806 struct rpc_xprt
*xprt
= req
->rq_xprt
;
808 dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
809 task
->tk_pid
, ntohl(req
->rq_xid
), copied
);
812 req
->rq_rtt
= ktime_sub(ktime_get(), req
->rq_xtime
);
813 if (xprt
->ops
->timer
!= NULL
)
814 xprt_update_rtt(task
);
816 list_del_init(&req
->rq_list
);
817 req
->rq_private_buf
.len
= copied
;
818 /* Ensure all writes are done before we update */
819 /* req->rq_reply_bytes_recvd */
821 req
->rq_reply_bytes_recvd
= copied
;
822 rpc_wake_up_queued_task(&xprt
->pending
, task
);
824 EXPORT_SYMBOL_GPL(xprt_complete_rqst
);
826 static void xprt_timer(struct rpc_task
*task
)
828 struct rpc_rqst
*req
= task
->tk_rqstp
;
829 struct rpc_xprt
*xprt
= req
->rq_xprt
;
831 if (task
->tk_status
!= -ETIMEDOUT
)
833 dprintk("RPC: %5u xprt_timer\n", task
->tk_pid
);
835 spin_lock_bh(&xprt
->transport_lock
);
836 if (!req
->rq_reply_bytes_recvd
) {
837 if (xprt
->ops
->timer
)
838 xprt
->ops
->timer(task
);
841 spin_unlock_bh(&xprt
->transport_lock
);
844 static inline int xprt_has_timer(struct rpc_xprt
*xprt
)
846 return xprt
->idle_timeout
!= 0;
850 * xprt_prepare_transmit - reserve the transport before sending a request
851 * @task: RPC task about to send a request
854 int xprt_prepare_transmit(struct rpc_task
*task
)
856 struct rpc_rqst
*req
= task
->tk_rqstp
;
857 struct rpc_xprt
*xprt
= req
->rq_xprt
;
860 dprintk("RPC: %5u xprt_prepare_transmit\n", task
->tk_pid
);
862 spin_lock_bh(&xprt
->transport_lock
);
863 if (req
->rq_reply_bytes_recvd
&& !req
->rq_bytes_sent
) {
864 err
= req
->rq_reply_bytes_recvd
;
867 if (!xprt
->ops
->reserve_xprt(xprt
, task
))
870 spin_unlock_bh(&xprt
->transport_lock
);
874 void xprt_end_transmit(struct rpc_task
*task
)
876 xprt_release_write(task
->tk_rqstp
->rq_xprt
, task
);
880 * xprt_transmit - send an RPC request on a transport
881 * @task: controlling RPC task
883 * We have to copy the iovec because sendmsg fiddles with its contents.
885 void xprt_transmit(struct rpc_task
*task
)
887 struct rpc_rqst
*req
= task
->tk_rqstp
;
888 struct rpc_xprt
*xprt
= req
->rq_xprt
;
891 dprintk("RPC: %5u xprt_transmit(%u)\n", task
->tk_pid
, req
->rq_slen
);
893 if (!req
->rq_reply_bytes_recvd
) {
894 if (list_empty(&req
->rq_list
) && rpc_reply_expected(task
)) {
896 * Add to the list only if we're expecting a reply
898 spin_lock_bh(&xprt
->transport_lock
);
899 /* Update the softirq receive buffer */
900 memcpy(&req
->rq_private_buf
, &req
->rq_rcv_buf
,
901 sizeof(req
->rq_private_buf
));
902 /* Add request to the receive list */
903 list_add_tail(&req
->rq_list
, &xprt
->recv
);
904 spin_unlock_bh(&xprt
->transport_lock
);
905 xprt_reset_majortimeo(req
);
906 /* Turn off autodisconnect */
907 del_singleshot_timer_sync(&xprt
->timer
);
909 } else if (!req
->rq_bytes_sent
)
912 req
->rq_connect_cookie
= xprt
->connect_cookie
;
913 req
->rq_xtime
= ktime_get();
914 status
= xprt
->ops
->send_request(task
);
916 task
->tk_status
= status
;
920 dprintk("RPC: %5u xmit complete\n", task
->tk_pid
);
921 task
->tk_flags
|= RPC_TASK_SENT
;
922 spin_lock_bh(&xprt
->transport_lock
);
924 xprt
->ops
->set_retrans_timeout(task
);
926 numreqs
= atomic_read(&xprt
->num_reqs
);
927 if (numreqs
> xprt
->stat
.max_slots
)
928 xprt
->stat
.max_slots
= numreqs
;
930 xprt
->stat
.req_u
+= xprt
->stat
.sends
- xprt
->stat
.recvs
;
931 xprt
->stat
.bklog_u
+= xprt
->backlog
.qlen
;
932 xprt
->stat
.sending_u
+= xprt
->sending
.qlen
;
933 xprt
->stat
.pending_u
+= xprt
->pending
.qlen
;
935 /* Don't race with disconnect */
936 if (!xprt_connected(xprt
))
937 task
->tk_status
= -ENOTCONN
;
938 else if (!req
->rq_reply_bytes_recvd
&& rpc_reply_expected(task
)) {
940 * Sleep on the pending queue since
941 * we're expecting a reply.
943 rpc_sleep_on(&xprt
->pending
, task
, xprt_timer
);
945 spin_unlock_bh(&xprt
->transport_lock
);
948 static struct rpc_rqst
*xprt_dynamic_alloc_slot(struct rpc_xprt
*xprt
, gfp_t gfp_flags
)
950 struct rpc_rqst
*req
= ERR_PTR(-EAGAIN
);
952 if (!atomic_add_unless(&xprt
->num_reqs
, 1, xprt
->max_reqs
))
954 req
= kzalloc(sizeof(struct rpc_rqst
), gfp_flags
);
957 atomic_dec(&xprt
->num_reqs
);
958 req
= ERR_PTR(-ENOMEM
);
963 static bool xprt_dynamic_free_slot(struct rpc_xprt
*xprt
, struct rpc_rqst
*req
)
965 if (atomic_add_unless(&xprt
->num_reqs
, -1, xprt
->min_reqs
)) {
972 void xprt_alloc_slot(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
974 struct rpc_rqst
*req
;
976 spin_lock(&xprt
->reserve_lock
);
977 if (!list_empty(&xprt
->free
)) {
978 req
= list_entry(xprt
->free
.next
, struct rpc_rqst
, rq_list
);
979 list_del(&req
->rq_list
);
982 req
= xprt_dynamic_alloc_slot(xprt
, GFP_NOWAIT
|__GFP_NOWARN
);
985 switch (PTR_ERR(req
)) {
987 dprintk("RPC: dynamic allocation of request slot "
988 "failed! Retrying\n");
989 task
->tk_status
= -ENOMEM
;
992 rpc_sleep_on(&xprt
->backlog
, task
, NULL
);
993 dprintk("RPC: waiting for request slot\n");
995 task
->tk_status
= -EAGAIN
;
997 spin_unlock(&xprt
->reserve_lock
);
1000 task
->tk_status
= 0;
1001 task
->tk_rqstp
= req
;
1002 xprt_request_init(task
, xprt
);
1003 spin_unlock(&xprt
->reserve_lock
);
1005 EXPORT_SYMBOL_GPL(xprt_alloc_slot
);
1007 void xprt_lock_and_alloc_slot(struct rpc_xprt
*xprt
, struct rpc_task
*task
)
1009 /* Note: grabbing the xprt_lock_write() ensures that we throttle
1010 * new slot allocation if the transport is congested (i.e. when
1011 * reconnecting a stream transport or when out of socket write
1014 if (xprt_lock_write(xprt
, task
)) {
1015 xprt_alloc_slot(xprt
, task
);
1016 xprt_release_write(xprt
, task
);
1019 EXPORT_SYMBOL_GPL(xprt_lock_and_alloc_slot
);
1021 static void xprt_free_slot(struct rpc_xprt
*xprt
, struct rpc_rqst
*req
)
1023 spin_lock(&xprt
->reserve_lock
);
1024 if (!xprt_dynamic_free_slot(xprt
, req
)) {
1025 memset(req
, 0, sizeof(*req
)); /* mark unused */
1026 list_add(&req
->rq_list
, &xprt
->free
);
1028 rpc_wake_up_next(&xprt
->backlog
);
1029 spin_unlock(&xprt
->reserve_lock
);
1032 static void xprt_free_all_slots(struct rpc_xprt
*xprt
)
1034 struct rpc_rqst
*req
;
1035 while (!list_empty(&xprt
->free
)) {
1036 req
= list_first_entry(&xprt
->free
, struct rpc_rqst
, rq_list
);
1037 list_del(&req
->rq_list
);
1042 struct rpc_xprt
*xprt_alloc(struct net
*net
, size_t size
,
1043 unsigned int num_prealloc
,
1044 unsigned int max_alloc
)
1046 struct rpc_xprt
*xprt
;
1047 struct rpc_rqst
*req
;
1050 xprt
= kzalloc(size
, GFP_KERNEL
);
1054 xprt_init(xprt
, net
);
1056 for (i
= 0; i
< num_prealloc
; i
++) {
1057 req
= kzalloc(sizeof(struct rpc_rqst
), GFP_KERNEL
);
1060 list_add(&req
->rq_list
, &xprt
->free
);
1062 if (i
< num_prealloc
)
1064 if (max_alloc
> num_prealloc
)
1065 xprt
->max_reqs
= max_alloc
;
1067 xprt
->max_reqs
= num_prealloc
;
1068 xprt
->min_reqs
= num_prealloc
;
1069 atomic_set(&xprt
->num_reqs
, num_prealloc
);
1078 EXPORT_SYMBOL_GPL(xprt_alloc
);
1080 void xprt_free(struct rpc_xprt
*xprt
)
1082 put_net(xprt
->xprt_net
);
1083 xprt_free_all_slots(xprt
);
1086 EXPORT_SYMBOL_GPL(xprt_free
);
1089 * xprt_reserve - allocate an RPC request slot
1090 * @task: RPC task requesting a slot allocation
1092 * If no more slots are available, place the task on the transport's
1095 void xprt_reserve(struct rpc_task
*task
)
1097 struct rpc_xprt
*xprt
= task
->tk_xprt
;
1099 task
->tk_status
= 0;
1100 if (task
->tk_rqstp
!= NULL
)
1103 task
->tk_timeout
= 0;
1104 task
->tk_status
= -EAGAIN
;
1105 xprt
->ops
->alloc_slot(xprt
, task
);
1108 static inline __be32
xprt_alloc_xid(struct rpc_xprt
*xprt
)
1110 return (__force __be32
)xprt
->xid
++;
1113 static inline void xprt_init_xid(struct rpc_xprt
*xprt
)
1115 xprt
->xid
= net_random();
1118 static void xprt_request_init(struct rpc_task
*task
, struct rpc_xprt
*xprt
)
1120 struct rpc_rqst
*req
= task
->tk_rqstp
;
1122 INIT_LIST_HEAD(&req
->rq_list
);
1123 req
->rq_timeout
= task
->tk_client
->cl_timeout
->to_initval
;
1124 req
->rq_task
= task
;
1125 req
->rq_xprt
= xprt
;
1126 req
->rq_buffer
= NULL
;
1127 req
->rq_xid
= xprt_alloc_xid(xprt
);
1128 req
->rq_release_snd_buf
= NULL
;
1129 xprt_reset_majortimeo(req
);
1130 dprintk("RPC: %5u reserved req %p xid %08x\n", task
->tk_pid
,
1131 req
, ntohl(req
->rq_xid
));
1135 * xprt_release - release an RPC request slot
1136 * @task: task which is finished with the slot
1139 void xprt_release(struct rpc_task
*task
)
1141 struct rpc_xprt
*xprt
;
1142 struct rpc_rqst
*req
;
1144 if (!(req
= task
->tk_rqstp
))
1147 xprt
= req
->rq_xprt
;
1148 if (task
->tk_ops
->rpc_count_stats
!= NULL
)
1149 task
->tk_ops
->rpc_count_stats(task
, task
->tk_calldata
);
1150 else if (task
->tk_client
)
1151 rpc_count_iostats(task
, task
->tk_client
->cl_metrics
);
1152 spin_lock_bh(&xprt
->transport_lock
);
1153 xprt
->ops
->release_xprt(xprt
, task
);
1154 if (xprt
->ops
->release_request
)
1155 xprt
->ops
->release_request(task
);
1156 if (!list_empty(&req
->rq_list
))
1157 list_del(&req
->rq_list
);
1158 xprt
->last_used
= jiffies
;
1159 if (list_empty(&xprt
->recv
) && xprt_has_timer(xprt
))
1160 mod_timer(&xprt
->timer
,
1161 xprt
->last_used
+ xprt
->idle_timeout
);
1162 spin_unlock_bh(&xprt
->transport_lock
);
1164 xprt
->ops
->buf_free(req
->rq_buffer
);
1165 if (req
->rq_cred
!= NULL
)
1166 put_rpccred(req
->rq_cred
);
1167 task
->tk_rqstp
= NULL
;
1168 if (req
->rq_release_snd_buf
)
1169 req
->rq_release_snd_buf(req
);
1171 dprintk("RPC: %5u release request %p\n", task
->tk_pid
, req
);
1172 if (likely(!bc_prealloc(req
)))
1173 xprt_free_slot(xprt
, req
);
1175 xprt_free_bc_request(req
);
1178 static void xprt_init(struct rpc_xprt
*xprt
, struct net
*net
)
1180 atomic_set(&xprt
->count
, 1);
1182 spin_lock_init(&xprt
->transport_lock
);
1183 spin_lock_init(&xprt
->reserve_lock
);
1185 INIT_LIST_HEAD(&xprt
->free
);
1186 INIT_LIST_HEAD(&xprt
->recv
);
1187 #if defined(CONFIG_SUNRPC_BACKCHANNEL)
1188 spin_lock_init(&xprt
->bc_pa_lock
);
1189 INIT_LIST_HEAD(&xprt
->bc_pa_list
);
1190 #endif /* CONFIG_SUNRPC_BACKCHANNEL */
1192 xprt
->last_used
= jiffies
;
1193 xprt
->cwnd
= RPC_INITCWND
;
1194 xprt
->bind_index
= 0;
1196 rpc_init_wait_queue(&xprt
->binding
, "xprt_binding");
1197 rpc_init_wait_queue(&xprt
->pending
, "xprt_pending");
1198 rpc_init_priority_wait_queue(&xprt
->sending
, "xprt_sending");
1199 rpc_init_priority_wait_queue(&xprt
->backlog
, "xprt_backlog");
1201 xprt_init_xid(xprt
);
1203 xprt
->xprt_net
= get_net(net
);
1207 * xprt_create_transport - create an RPC transport
1208 * @args: rpc transport creation arguments
1211 struct rpc_xprt
*xprt_create_transport(struct xprt_create
*args
)
1213 struct rpc_xprt
*xprt
;
1214 struct xprt_class
*t
;
1216 spin_lock(&xprt_list_lock
);
1217 list_for_each_entry(t
, &xprt_list
, list
) {
1218 if (t
->ident
== args
->ident
) {
1219 spin_unlock(&xprt_list_lock
);
1223 spin_unlock(&xprt_list_lock
);
1224 printk(KERN_ERR
"RPC: transport (%d) not supported\n", args
->ident
);
1225 return ERR_PTR(-EIO
);
1228 xprt
= t
->setup(args
);
1230 dprintk("RPC: xprt_create_transport: failed, %ld\n",
1234 INIT_WORK(&xprt
->task_cleanup
, xprt_autoclose
);
1235 if (xprt_has_timer(xprt
))
1236 setup_timer(&xprt
->timer
, xprt_init_autodisconnect
,
1237 (unsigned long)xprt
);
1239 init_timer(&xprt
->timer
);
1241 if (strlen(args
->servername
) > RPC_MAXNETNAMELEN
) {
1243 return ERR_PTR(-EINVAL
);
1245 xprt
->servername
= kstrdup(args
->servername
, GFP_KERNEL
);
1246 if (xprt
->servername
== NULL
) {
1248 return ERR_PTR(-ENOMEM
);
1251 dprintk("RPC: created transport %p with %u slots\n", xprt
,
1258 * xprt_destroy - destroy an RPC transport, killing off all requests.
1259 * @xprt: transport to destroy
1262 static void xprt_destroy(struct rpc_xprt
*xprt
)
1264 dprintk("RPC: destroying transport %p\n", xprt
);
1266 del_timer_sync(&xprt
->timer
);
1268 rpc_destroy_wait_queue(&xprt
->binding
);
1269 rpc_destroy_wait_queue(&xprt
->pending
);
1270 rpc_destroy_wait_queue(&xprt
->sending
);
1271 rpc_destroy_wait_queue(&xprt
->backlog
);
1272 cancel_work_sync(&xprt
->task_cleanup
);
1273 kfree(xprt
->servername
);
1275 * Tear down transport state and free the rpc_xprt
1277 xprt
->ops
->destroy(xprt
);
1281 * xprt_put - release a reference to an RPC transport.
1282 * @xprt: pointer to the transport
1285 void xprt_put(struct rpc_xprt
*xprt
)
1287 if (atomic_dec_and_test(&xprt
->count
))
1292 * xprt_get - return a reference to an RPC transport.
1293 * @xprt: pointer to the transport
1296 struct rpc_xprt
*xprt_get(struct rpc_xprt
*xprt
)
1298 if (atomic_inc_not_zero(&xprt
->count
))