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1/*
2 * linux/net/sunrpc/xprt.c
3 *
4 * This is a generic RPC call interface supporting congestion avoidance,
5 * and asynchronous calls.
6 *
7 * The interface works like this:
8 *
9 * - When a process places a call, it allocates a request slot if
10 * one is available. Otherwise, it sleeps on the backlog queue
11 * (xprt_reserve).
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
17 * expired.
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
24 * of -ETIMEDOUT.
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
29 * again.
30 *
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.
34 *
35 * Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de>
36 *
37 * Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com>
38 */
39
40#include <linux/module.h>
41
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>
47
48#include <linux/sunrpc/clnt.h>
49#include <linux/sunrpc/metrics.h>
50#include <linux/sunrpc/bc_xprt.h>
51
52#include "sunrpc.h"
53
54/*
55 * Local variables
56 */
57
58#ifdef RPC_DEBUG
59# define RPCDBG_FACILITY RPCDBG_XPRT
60#endif
61
62/*
63 * Local functions
64 */
65static void xprt_init(struct rpc_xprt *xprt, struct net *net);
66static void xprt_request_init(struct rpc_task *, struct rpc_xprt *);
67static void xprt_connect_status(struct rpc_task *task);
68static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
69static void xprt_destroy(struct rpc_xprt *xprt);
70
71static DEFINE_SPINLOCK(xprt_list_lock);
72static LIST_HEAD(xprt_list);
73
74/*
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
80 *
81 * - a reply is received and
82 * - a full number of requests are outstanding and
83 * - the congestion window hasn't been updated recently.
84 */
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)
89
90#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
91
92/**
93 * xprt_register_transport - register a transport implementation
94 * @transport: transport to register
95 *
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.
98 *
99 * Returns:
100 * 0: transport successfully registered
101 * -EEXIST: transport already registered
102 * -EINVAL: transport module being unloaded
103 */
104int xprt_register_transport(struct xprt_class *transport)
105{
106 struct xprt_class *t;
107 int result;
108
109 result = -EEXIST;
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)
114 goto out;
115 }
116
117 list_add_tail(&transport->list, &xprt_list);
118 printk(KERN_INFO "RPC: Registered %s transport module.\n",
119 transport->name);
120 result = 0;
121
122out:
123 spin_unlock(&xprt_list_lock);
124 return result;
125}
126EXPORT_SYMBOL_GPL(xprt_register_transport);
127
128/**
129 * xprt_unregister_transport - unregister a transport implementation
130 * @transport: transport to unregister
131 *
132 * Returns:
133 * 0: transport successfully unregistered
134 * -ENOENT: transport never registered
135 */
136int xprt_unregister_transport(struct xprt_class *transport)
137{
138 struct xprt_class *t;
139 int result;
140
141 result = 0;
142 spin_lock(&xprt_list_lock);
143 list_for_each_entry(t, &xprt_list, list) {
144 if (t == transport) {
145 printk(KERN_INFO
146 "RPC: Unregistered %s transport module.\n",
147 transport->name);
148 list_del_init(&transport->list);
149 goto out;
150 }
151 }
152 result = -ENOENT;
153
154out:
155 spin_unlock(&xprt_list_lock);
156 return result;
157}
158EXPORT_SYMBOL_GPL(xprt_unregister_transport);
159
160/**
161 * xprt_load_transport - load a transport implementation
162 * @transport_name: transport to load
163 *
164 * Returns:
165 * 0: transport successfully loaded
166 * -ENOENT: transport module not available
167 */
168int xprt_load_transport(const char *transport_name)
169{
170 struct xprt_class *t;
171 int result;
172
173 result = 0;
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);
178 goto out;
179 }
180 }
181 spin_unlock(&xprt_list_lock);
182 result = request_module("xprt%s", transport_name);
183out:
184 return result;
185}
186EXPORT_SYMBOL_GPL(xprt_load_transport);
187
188/**
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
192 *
193 * This prevents mixing the payload of separate requests, and prevents
194 * transport connects from colliding with writes. No congestion control
195 * is provided.
196 */
197int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
198{
199 struct rpc_rqst *req = task->tk_rqstp;
200 int priority;
201
202 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
203 if (task == xprt->snd_task)
204 return 1;
205 goto out_sleep;
206 }
207 xprt->snd_task = task;
208 if (req != NULL) {
209 req->rq_bytes_sent = 0;
210 req->rq_ntrans++;
211 }
212
213 return 1;
214
215out_sleep:
216 dprintk("RPC: %5u failed to lock transport %p\n",
217 task->tk_pid, xprt);
218 task->tk_timeout = 0;
219 task->tk_status = -EAGAIN;
220 if (req == NULL)
221 priority = RPC_PRIORITY_LOW;
222 else if (!req->rq_ntrans)
223 priority = RPC_PRIORITY_NORMAL;
224 else
225 priority = RPC_PRIORITY_HIGH;
226 rpc_sleep_on_priority(&xprt->sending, task, NULL, priority);
227 return 0;
228}
229EXPORT_SYMBOL_GPL(xprt_reserve_xprt);
230
231static void xprt_clear_locked(struct rpc_xprt *xprt)
232{
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();
238 } else
239 queue_work(rpciod_workqueue, &xprt->task_cleanup);
240}
241
242/*
243 * xprt_reserve_xprt_cong - serialize write access to transports
244 * @task: task that is requesting access to the transport
245 *
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.
249 */
250int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
251{
252 struct rpc_rqst *req = task->tk_rqstp;
253 int priority;
254
255 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
256 if (task == xprt->snd_task)
257 return 1;
258 goto out_sleep;
259 }
260 if (req == NULL) {
261 xprt->snd_task = task;
262 return 1;
263 }
264 if (__xprt_get_cong(xprt, task)) {
265 xprt->snd_task = task;
266 req->rq_bytes_sent = 0;
267 req->rq_ntrans++;
268 return 1;
269 }
270 xprt_clear_locked(xprt);
271out_sleep:
272 dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt);
273 task->tk_timeout = 0;
274 task->tk_status = -EAGAIN;
275 if (req == NULL)
276 priority = RPC_PRIORITY_LOW;
277 else if (!req->rq_ntrans)
278 priority = RPC_PRIORITY_NORMAL;
279 else
280 priority = RPC_PRIORITY_HIGH;
281 rpc_sleep_on_priority(&xprt->sending, task, NULL, priority);
282 return 0;
283}
284EXPORT_SYMBOL_GPL(xprt_reserve_xprt_cong);
285
286static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
287{
288 int retval;
289
290 spin_lock_bh(&xprt->transport_lock);
291 retval = xprt->ops->reserve_xprt(xprt, task);
292 spin_unlock_bh(&xprt->transport_lock);
293 return retval;
294}
295
296static bool __xprt_lock_write_func(struct rpc_task *task, void *data)
297{
298 struct rpc_xprt *xprt = data;
299 struct rpc_rqst *req;
300
301 req = task->tk_rqstp;
302 xprt->snd_task = task;
303 if (req) {
304 req->rq_bytes_sent = 0;
305 req->rq_ntrans++;
306 }
307 return true;
308}
309
310static void __xprt_lock_write_next(struct rpc_xprt *xprt)
311{
312 if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
313 return;
314
315 if (rpc_wake_up_first(&xprt->sending, __xprt_lock_write_func, xprt))
316 return;
317 xprt_clear_locked(xprt);
318}
319
320static bool __xprt_lock_write_cong_func(struct rpc_task *task, void *data)
321{
322 struct rpc_xprt *xprt = data;
323 struct rpc_rqst *req;
324
325 req = task->tk_rqstp;
326 if (req == NULL) {
327 xprt->snd_task = task;
328 return true;
329 }
330 if (__xprt_get_cong(xprt, task)) {
331 xprt->snd_task = task;
332 req->rq_bytes_sent = 0;
333 req->rq_ntrans++;
334 return true;
335 }
336 return false;
337}
338
339static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
340{
341 if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
342 return;
343 if (RPCXPRT_CONGESTED(xprt))
344 goto out_unlock;
345 if (rpc_wake_up_first(&xprt->sending, __xprt_lock_write_cong_func, xprt))
346 return;
347out_unlock:
348 xprt_clear_locked(xprt);
349}
350
351/**
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
355 *
356 * Note that "task" can be NULL. No congestion control is provided.
357 */
358void xprt_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
359{
360 if (xprt->snd_task == task) {
361 xprt_clear_locked(xprt);
362 __xprt_lock_write_next(xprt);
363 }
364}
365EXPORT_SYMBOL_GPL(xprt_release_xprt);
366
367/**
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
371 *
372 * Note that "task" can be NULL. Another task is awoken to use the
373 * transport if the transport's congestion window allows it.
374 */
375void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
376{
377 if (xprt->snd_task == task) {
378 xprt_clear_locked(xprt);
379 __xprt_lock_write_next_cong(xprt);
380 }
381}
382EXPORT_SYMBOL_GPL(xprt_release_xprt_cong);
383
384static inline void xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
385{
386 spin_lock_bh(&xprt->transport_lock);
387 xprt->ops->release_xprt(xprt, task);
388 spin_unlock_bh(&xprt->transport_lock);
389}
390
391/*
392 * Van Jacobson congestion avoidance. Check if the congestion window
393 * overflowed. Put the task to sleep if this is the case.
394 */
395static int
396__xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task)
397{
398 struct rpc_rqst *req = task->tk_rqstp;
399
400 if (req->rq_cong)
401 return 1;
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))
405 return 0;
406 req->rq_cong = 1;
407 xprt->cong += RPC_CWNDSCALE;
408 return 1;
409}
410
411/*
412 * Adjust the congestion window, and wake up the next task
413 * that has been sleeping due to congestion
414 */
415static void
416__xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
417{
418 if (!req->rq_cong)
419 return;
420 req->rq_cong = 0;
421 xprt->cong -= RPC_CWNDSCALE;
422 __xprt_lock_write_next_cong(xprt);
423}
424
425/**
426 * xprt_release_rqst_cong - housekeeping when request is complete
427 * @task: RPC request that recently completed
428 *
429 * Useful for transports that require congestion control.
430 */
431void xprt_release_rqst_cong(struct rpc_task *task)
432{
433 __xprt_put_cong(task->tk_xprt, task->tk_rqstp);
434}
435EXPORT_SYMBOL_GPL(xprt_release_rqst_cong);
436
437/**
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
441 *
442 * We use a time-smoothed congestion estimator to avoid heavy oscillation.
443 */
444void xprt_adjust_cwnd(struct rpc_task *task, int result)
445{
446 struct rpc_rqst *req = task->tk_rqstp;
447 struct rpc_xprt *xprt = task->tk_xprt;
448 unsigned long cwnd = xprt->cwnd;
449
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) {
458 cwnd >>= 1;
459 if (cwnd < RPC_CWNDSCALE)
460 cwnd = RPC_CWNDSCALE;
461 }
462 dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n",
463 xprt->cong, xprt->cwnd, cwnd);
464 xprt->cwnd = cwnd;
465 __xprt_put_cong(xprt, req);
466}
467EXPORT_SYMBOL_GPL(xprt_adjust_cwnd);
468
469/**
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
473 *
474 */
475void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status)
476{
477 if (status < 0)
478 rpc_wake_up_status(&xprt->pending, status);
479 else
480 rpc_wake_up(&xprt->pending);
481}
482EXPORT_SYMBOL_GPL(xprt_wake_pending_tasks);
483
484/**
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
488 */
489void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action)
490{
491 struct rpc_rqst *req = task->tk_rqstp;
492 struct rpc_xprt *xprt = req->rq_xprt;
493
494 task->tk_timeout = req->rq_timeout;
495 rpc_sleep_on(&xprt->pending, task, action);
496}
497EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space);
498
499/**
500 * xprt_write_space - wake the task waiting for transport output buffer space
501 * @xprt: transport with waiting tasks
502 *
503 * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
504 */
505void xprt_write_space(struct rpc_xprt *xprt)
506{
507 if (unlikely(xprt->shutdown))
508 return;
509
510 spin_lock_bh(&xprt->transport_lock);
511 if (xprt->snd_task) {
512 dprintk("RPC: write space: waking waiting task on "
513 "xprt %p\n", xprt);
514 rpc_wake_up_queued_task(&xprt->pending, xprt->snd_task);
515 }
516 spin_unlock_bh(&xprt->transport_lock);
517}
518EXPORT_SYMBOL_GPL(xprt_write_space);
519
520/**
521 * xprt_set_retrans_timeout_def - set a request's retransmit timeout
522 * @task: task whose timeout is to be set
523 *
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.
527 */
528void xprt_set_retrans_timeout_def(struct rpc_task *task)
529{
530 task->tk_timeout = task->tk_rqstp->rq_timeout;
531}
532EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_def);
533
534/*
535 * xprt_set_retrans_timeout_rtt - set a request's retransmit timeout
536 * @task: task whose timeout is to be set
537 *
538 * Set a request's retransmit timeout using the RTT estimator.
539 */
540void xprt_set_retrans_timeout_rtt(struct rpc_task *task)
541{
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;
547
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;
552}
553EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_rtt);
554
555static void xprt_reset_majortimeo(struct rpc_rqst *req)
556{
557 const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout;
558
559 req->rq_majortimeo = req->rq_timeout;
560 if (to->to_exponential)
561 req->rq_majortimeo <<= to->to_retries;
562 else
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;
567}
568
569/**
570 * xprt_adjust_timeout - adjust timeout values for next retransmit
571 * @req: RPC request containing parameters to use for the adjustment
572 *
573 */
574int xprt_adjust_timeout(struct rpc_rqst *req)
575{
576 struct rpc_xprt *xprt = req->rq_xprt;
577 const struct rpc_timeout *to = req->rq_task->tk_client->cl_timeout;
578 int status = 0;
579
580 if (time_before(jiffies, req->rq_majortimeo)) {
581 if (to->to_exponential)
582 req->rq_timeout <<= 1;
583 else
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;
587 req->rq_retries++;
588 } else {
589 req->rq_timeout = to->to_initval;
590 req->rq_retries = 0;
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);
596 status = -ETIMEDOUT;
597 }
598
599 if (req->rq_timeout == 0) {
600 printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n");
601 req->rq_timeout = 5 * HZ;
602 }
603 return status;
604}
605
606static void xprt_autoclose(struct work_struct *work)
607{
608 struct rpc_xprt *xprt =
609 container_of(work, struct rpc_xprt, task_cleanup);
610
611 xprt->ops->close(xprt);
612 clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
613 xprt_release_write(xprt, NULL);
614}
615
616/**
617 * xprt_disconnect_done - mark a transport as disconnected
618 * @xprt: transport to flag for disconnect
619 *
620 */
621void xprt_disconnect_done(struct rpc_xprt *xprt)
622{
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);
628}
629EXPORT_SYMBOL_GPL(xprt_disconnect_done);
630
631/**
632 * xprt_force_disconnect - force a transport to disconnect
633 * @xprt: transport to disconnect
634 *
635 */
636void xprt_force_disconnect(struct rpc_xprt *xprt)
637{
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);
646}
647
648/**
649 * xprt_conditional_disconnect - force a transport to disconnect
650 * @xprt: transport to disconnect
651 * @cookie: 'connection cookie'
652 *
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.
657 *
658 */
659void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie)
660{
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)
664 goto out;
665 if (test_bit(XPRT_CLOSING, &xprt->state) || !xprt_connected(xprt))
666 goto out;
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);
672out:
673 spin_unlock_bh(&xprt->transport_lock);
674}
675
676static void
677xprt_init_autodisconnect(unsigned long data)
678{
679 struct rpc_xprt *xprt = (struct rpc_xprt *)data;
680
681 spin_lock(&xprt->transport_lock);
682 if (!list_empty(&xprt->recv) || xprt->shutdown)
683 goto out_abort;
684 if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
685 goto out_abort;
686 spin_unlock(&xprt->transport_lock);
687 set_bit(XPRT_CONNECTION_CLOSE, &xprt->state);
688 queue_work(rpciod_workqueue, &xprt->task_cleanup);
689 return;
690out_abort:
691 spin_unlock(&xprt->transport_lock);
692}
693
694/**
695 * xprt_connect - schedule a transport connect operation
696 * @task: RPC task that is requesting the connect
697 *
698 */
699void xprt_connect(struct rpc_task *task)
700{
701 struct rpc_xprt *xprt = task->tk_xprt;
702
703 dprintk("RPC: %5u xprt_connect xprt %p %s connected\n", task->tk_pid,
704 xprt, (xprt_connected(xprt) ? "is" : "is not"));
705
706 if (!xprt_bound(xprt)) {
707 task->tk_status = -EAGAIN;
708 return;
709 }
710 if (!xprt_lock_write(xprt, task))
711 return;
712
713 if (test_and_clear_bit(XPRT_CLOSE_WAIT, &xprt->state))
714 xprt->ops->close(xprt);
715
716 if (xprt_connected(xprt))
717 xprt_release_write(xprt, task);
718 else {
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);
722
723 if (test_bit(XPRT_CLOSING, &xprt->state))
724 return;
725 if (xprt_test_and_set_connecting(xprt))
726 return;
727 xprt->stat.connect_start = jiffies;
728 xprt->ops->connect(task);
729 }
730}
731
732static void xprt_connect_status(struct rpc_task *task)
733{
734 struct rpc_xprt *xprt = task->tk_xprt;
735
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",
740 task->tk_pid);
741 return;
742 }
743
744 switch (task->tk_status) {
745 case -EAGAIN:
746 dprintk("RPC: %5u xprt_connect_status: retrying\n", task->tk_pid);
747 break;
748 case -ETIMEDOUT:
749 dprintk("RPC: %5u xprt_connect_status: connect attempt timed "
750 "out\n", task->tk_pid);
751 break;
752 default:
753 dprintk("RPC: %5u xprt_connect_status: error %d connecting to "
754 "server %s\n", task->tk_pid, -task->tk_status,
755 xprt->servername);
756 xprt_release_write(xprt, task);
757 task->tk_status = -EIO;
758 }
759}
760
761/**
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
765 *
766 */
767struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, __be32 xid)
768{
769 struct rpc_rqst *entry;
770
771 list_for_each_entry(entry, &xprt->recv, rq_list)
772 if (entry->rq_xid == xid)
773 return entry;
774
775 dprintk("RPC: xprt_lookup_rqst did not find xid %08x\n",
776 ntohl(xid));
777 xprt->stat.bad_xids++;
778 return NULL;
779}
780EXPORT_SYMBOL_GPL(xprt_lookup_rqst);
781
782static void xprt_update_rtt(struct rpc_task *task)
783{
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));
788
789 if (timer) {
790 if (req->rq_ntrans == 1)
791 rpc_update_rtt(rtt, timer, m);
792 rpc_set_timeo(rtt, timer, req->rq_ntrans - 1);
793 }
794}
795
796/**
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
800 *
801 * Caller holds transport lock.
802 */
803void xprt_complete_rqst(struct rpc_task *task, int copied)
804{
805 struct rpc_rqst *req = task->tk_rqstp;
806 struct rpc_xprt *xprt = req->rq_xprt;
807
808 dprintk("RPC: %5u xid %08x complete (%d bytes received)\n",
809 task->tk_pid, ntohl(req->rq_xid), copied);
810
811 xprt->stat.recvs++;
812 req->rq_rtt = ktime_sub(ktime_get(), req->rq_xtime);
813 if (xprt->ops->timer != NULL)
814 xprt_update_rtt(task);
815
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 */
820 smp_wmb();
821 req->rq_reply_bytes_recvd = copied;
822 rpc_wake_up_queued_task(&xprt->pending, task);
823}
824EXPORT_SYMBOL_GPL(xprt_complete_rqst);
825
826static void xprt_timer(struct rpc_task *task)
827{
828 struct rpc_rqst *req = task->tk_rqstp;
829 struct rpc_xprt *xprt = req->rq_xprt;
830
831 if (task->tk_status != -ETIMEDOUT)
832 return;
833 dprintk("RPC: %5u xprt_timer\n", task->tk_pid);
834
835 spin_lock_bh(&xprt->transport_lock);
836 if (!req->rq_reply_bytes_recvd) {
837 if (xprt->ops->timer)
838 xprt->ops->timer(task);
839 } else
840 task->tk_status = 0;
841 spin_unlock_bh(&xprt->transport_lock);
842}
843
844static inline int xprt_has_timer(struct rpc_xprt *xprt)
845{
846 return xprt->idle_timeout != 0;
847}
848
849/**
850 * xprt_prepare_transmit - reserve the transport before sending a request
851 * @task: RPC task about to send a request
852 *
853 */
854int xprt_prepare_transmit(struct rpc_task *task)
855{
856 struct rpc_rqst *req = task->tk_rqstp;
857 struct rpc_xprt *xprt = req->rq_xprt;
858 int err = 0;
859
860 dprintk("RPC: %5u xprt_prepare_transmit\n", task->tk_pid);
861
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;
865 goto out_unlock;
866 }
867 if (!xprt->ops->reserve_xprt(xprt, task))
868 err = -EAGAIN;
869out_unlock:
870 spin_unlock_bh(&xprt->transport_lock);
871 return err;
872}
873
874void xprt_end_transmit(struct rpc_task *task)
875{
876 xprt_release_write(task->tk_rqstp->rq_xprt, task);
877}
878
879/**
880 * xprt_transmit - send an RPC request on a transport
881 * @task: controlling RPC task
882 *
883 * We have to copy the iovec because sendmsg fiddles with its contents.
884 */
885void xprt_transmit(struct rpc_task *task)
886{
887 struct rpc_rqst *req = task->tk_rqstp;
888 struct rpc_xprt *xprt = req->rq_xprt;
889 int status, numreqs;
890
891 dprintk("RPC: %5u xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
892
893 if (!req->rq_reply_bytes_recvd) {
894 if (list_empty(&req->rq_list) && rpc_reply_expected(task)) {
895 /*
896 * Add to the list only if we're expecting a reply
897 */
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);
908 }
909 } else if (!req->rq_bytes_sent)
910 return;
911
912 req->rq_connect_cookie = xprt->connect_cookie;
913 req->rq_xtime = ktime_get();
914 status = xprt->ops->send_request(task);
915 if (status != 0) {
916 task->tk_status = status;
917 return;
918 }
919
920 dprintk("RPC: %5u xmit complete\n", task->tk_pid);
921 task->tk_flags |= RPC_TASK_SENT;
922 spin_lock_bh(&xprt->transport_lock);
923
924 xprt->ops->set_retrans_timeout(task);
925
926 numreqs = atomic_read(&xprt->num_reqs);
927 if (numreqs > xprt->stat.max_slots)
928 xprt->stat.max_slots = numreqs;
929 xprt->stat.sends++;
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;
934
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)) {
939 /*
940 * Sleep on the pending queue since
941 * we're expecting a reply.
942 */
943 rpc_sleep_on(&xprt->pending, task, xprt_timer);
944 }
945 spin_unlock_bh(&xprt->transport_lock);
946}
947
948static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt, gfp_t gfp_flags)
949{
950 struct rpc_rqst *req = ERR_PTR(-EAGAIN);
951
952 if (!atomic_add_unless(&xprt->num_reqs, 1, xprt->max_reqs))
953 goto out;
954 req = kzalloc(sizeof(struct rpc_rqst), gfp_flags);
955 if (req != NULL)
956 goto out;
957 atomic_dec(&xprt->num_reqs);
958 req = ERR_PTR(-ENOMEM);
959out:
960 return req;
961}
962
963static bool xprt_dynamic_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
964{
965 if (atomic_add_unless(&xprt->num_reqs, -1, xprt->min_reqs)) {
966 kfree(req);
967 return true;
968 }
969 return false;
970}
971
972static void xprt_alloc_slot(struct rpc_task *task)
973{
974 struct rpc_xprt *xprt = task->tk_xprt;
975 struct rpc_rqst *req;
976
977 if (!list_empty(&xprt->free)) {
978 req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
979 list_del(&req->rq_list);
980 goto out_init_req;
981 }
982 req = xprt_dynamic_alloc_slot(xprt, GFP_NOWAIT|__GFP_NOWARN);
983 if (!IS_ERR(req))
984 goto out_init_req;
985 switch (PTR_ERR(req)) {
986 case -ENOMEM:
987 dprintk("RPC: dynamic allocation of request slot "
988 "failed! Retrying\n");
989 task->tk_status = -ENOMEM;
990 break;
991 case -EAGAIN:
992 rpc_sleep_on(&xprt->backlog, task, NULL);
993 dprintk("RPC: waiting for request slot\n");
994 default:
995 task->tk_status = -EAGAIN;
996 }
997 return;
998out_init_req:
999 task->tk_status = 0;
1000 task->tk_rqstp = req;
1001 xprt_request_init(task, xprt);
1002}
1003
1004static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req)
1005{
1006 spin_lock(&xprt->reserve_lock);
1007 if (!xprt_dynamic_free_slot(xprt, req)) {
1008 memset(req, 0, sizeof(*req)); /* mark unused */
1009 list_add(&req->rq_list, &xprt->free);
1010 }
1011 rpc_wake_up_next(&xprt->backlog);
1012 spin_unlock(&xprt->reserve_lock);
1013}
1014
1015static void xprt_free_all_slots(struct rpc_xprt *xprt)
1016{
1017 struct rpc_rqst *req;
1018 while (!list_empty(&xprt->free)) {
1019 req = list_first_entry(&xprt->free, struct rpc_rqst, rq_list);
1020 list_del(&req->rq_list);
1021 kfree(req);
1022 }
1023}
1024
1025struct rpc_xprt *xprt_alloc(struct net *net, size_t size,
1026 unsigned int num_prealloc,
1027 unsigned int max_alloc)
1028{
1029 struct rpc_xprt *xprt;
1030 struct rpc_rqst *req;
1031 int i;
1032
1033 xprt = kzalloc(size, GFP_KERNEL);
1034 if (xprt == NULL)
1035 goto out;
1036
1037 xprt_init(xprt, net);
1038
1039 for (i = 0; i < num_prealloc; i++) {
1040 req = kzalloc(sizeof(struct rpc_rqst), GFP_KERNEL);
1041 if (!req)
1042 break;
1043 list_add(&req->rq_list, &xprt->free);
1044 }
1045 if (i < num_prealloc)
1046 goto out_free;
1047 if (max_alloc > num_prealloc)
1048 xprt->max_reqs = max_alloc;
1049 else
1050 xprt->max_reqs = num_prealloc;
1051 xprt->min_reqs = num_prealloc;
1052 atomic_set(&xprt->num_reqs, num_prealloc);
1053
1054 return xprt;
1055
1056out_free:
1057 xprt_free(xprt);
1058out:
1059 return NULL;
1060}
1061EXPORT_SYMBOL_GPL(xprt_alloc);
1062
1063void xprt_free(struct rpc_xprt *xprt)
1064{
1065 put_net(xprt->xprt_net);
1066 xprt_free_all_slots(xprt);
1067 kfree(xprt);
1068}
1069EXPORT_SYMBOL_GPL(xprt_free);
1070
1071/**
1072 * xprt_reserve - allocate an RPC request slot
1073 * @task: RPC task requesting a slot allocation
1074 *
1075 * If no more slots are available, place the task on the transport's
1076 * backlog queue.
1077 */
1078void xprt_reserve(struct rpc_task *task)
1079{
1080 struct rpc_xprt *xprt = task->tk_xprt;
1081
1082 task->tk_status = 0;
1083 if (task->tk_rqstp != NULL)
1084 return;
1085
1086 /* Note: grabbing the xprt_lock_write() here is not strictly needed,
1087 * but ensures that we throttle new slot allocation if the transport
1088 * is congested (e.g. if reconnecting or if we're out of socket
1089 * write buffer space).
1090 */
1091 task->tk_timeout = 0;
1092 task->tk_status = -EAGAIN;
1093 if (!xprt_lock_write(xprt, task))
1094 return;
1095
1096 spin_lock(&xprt->reserve_lock);
1097 xprt_alloc_slot(task);
1098 spin_unlock(&xprt->reserve_lock);
1099 xprt_release_write(xprt, task);
1100}
1101
1102static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt)
1103{
1104 return (__force __be32)xprt->xid++;
1105}
1106
1107static inline void xprt_init_xid(struct rpc_xprt *xprt)
1108{
1109 xprt->xid = net_random();
1110}
1111
1112static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
1113{
1114 struct rpc_rqst *req = task->tk_rqstp;
1115
1116 INIT_LIST_HEAD(&req->rq_list);
1117 req->rq_timeout = task->tk_client->cl_timeout->to_initval;
1118 req->rq_task = task;
1119 req->rq_xprt = xprt;
1120 req->rq_buffer = NULL;
1121 req->rq_xid = xprt_alloc_xid(xprt);
1122 req->rq_release_snd_buf = NULL;
1123 xprt_reset_majortimeo(req);
1124 dprintk("RPC: %5u reserved req %p xid %08x\n", task->tk_pid,
1125 req, ntohl(req->rq_xid));
1126}
1127
1128/**
1129 * xprt_release - release an RPC request slot
1130 * @task: task which is finished with the slot
1131 *
1132 */
1133void xprt_release(struct rpc_task *task)
1134{
1135 struct rpc_xprt *xprt;
1136 struct rpc_rqst *req;
1137
1138 if (!(req = task->tk_rqstp))
1139 return;
1140
1141 xprt = req->rq_xprt;
1142 if (task->tk_ops->rpc_count_stats != NULL)
1143 task->tk_ops->rpc_count_stats(task, task->tk_calldata);
1144 else if (task->tk_client)
1145 rpc_count_iostats(task, task->tk_client->cl_metrics);
1146 spin_lock_bh(&xprt->transport_lock);
1147 xprt->ops->release_xprt(xprt, task);
1148 if (xprt->ops->release_request)
1149 xprt->ops->release_request(task);
1150 if (!list_empty(&req->rq_list))
1151 list_del(&req->rq_list);
1152 xprt->last_used = jiffies;
1153 if (list_empty(&xprt->recv) && xprt_has_timer(xprt))
1154 mod_timer(&xprt->timer,
1155 xprt->last_used + xprt->idle_timeout);
1156 spin_unlock_bh(&xprt->transport_lock);
1157 if (req->rq_buffer)
1158 xprt->ops->buf_free(req->rq_buffer);
1159 if (req->rq_cred != NULL)
1160 put_rpccred(req->rq_cred);
1161 task->tk_rqstp = NULL;
1162 if (req->rq_release_snd_buf)
1163 req->rq_release_snd_buf(req);
1164
1165 dprintk("RPC: %5u release request %p\n", task->tk_pid, req);
1166 if (likely(!bc_prealloc(req)))
1167 xprt_free_slot(xprt, req);
1168 else
1169 xprt_free_bc_request(req);
1170}
1171
1172static void xprt_init(struct rpc_xprt *xprt, struct net *net)
1173{
1174 atomic_set(&xprt->count, 1);
1175
1176 spin_lock_init(&xprt->transport_lock);
1177 spin_lock_init(&xprt->reserve_lock);
1178
1179 INIT_LIST_HEAD(&xprt->free);
1180 INIT_LIST_HEAD(&xprt->recv);
1181#if defined(CONFIG_SUNRPC_BACKCHANNEL)
1182 spin_lock_init(&xprt->bc_pa_lock);
1183 INIT_LIST_HEAD(&xprt->bc_pa_list);
1184#endif /* CONFIG_SUNRPC_BACKCHANNEL */
1185
1186 xprt->last_used = jiffies;
1187 xprt->cwnd = RPC_INITCWND;
1188 xprt->bind_index = 0;
1189
1190 rpc_init_wait_queue(&xprt->binding, "xprt_binding");
1191 rpc_init_wait_queue(&xprt->pending, "xprt_pending");
1192 rpc_init_priority_wait_queue(&xprt->sending, "xprt_sending");
1193 rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
1194
1195 xprt_init_xid(xprt);
1196
1197 xprt->xprt_net = get_net(net);
1198}
1199
1200/**
1201 * xprt_create_transport - create an RPC transport
1202 * @args: rpc transport creation arguments
1203 *
1204 */
1205struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
1206{
1207 struct rpc_xprt *xprt;
1208 struct xprt_class *t;
1209
1210 spin_lock(&xprt_list_lock);
1211 list_for_each_entry(t, &xprt_list, list) {
1212 if (t->ident == args->ident) {
1213 spin_unlock(&xprt_list_lock);
1214 goto found;
1215 }
1216 }
1217 spin_unlock(&xprt_list_lock);
1218 printk(KERN_ERR "RPC: transport (%d) not supported\n", args->ident);
1219 return ERR_PTR(-EIO);
1220
1221found:
1222 xprt = t->setup(args);
1223 if (IS_ERR(xprt)) {
1224 dprintk("RPC: xprt_create_transport: failed, %ld\n",
1225 -PTR_ERR(xprt));
1226 goto out;
1227 }
1228 INIT_WORK(&xprt->task_cleanup, xprt_autoclose);
1229 if (xprt_has_timer(xprt))
1230 setup_timer(&xprt->timer, xprt_init_autodisconnect,
1231 (unsigned long)xprt);
1232 else
1233 init_timer(&xprt->timer);
1234
1235 if (strlen(args->servername) > RPC_MAXNETNAMELEN) {
1236 xprt_destroy(xprt);
1237 return ERR_PTR(-EINVAL);
1238 }
1239 xprt->servername = kstrdup(args->servername, GFP_KERNEL);
1240 if (xprt->servername == NULL) {
1241 xprt_destroy(xprt);
1242 return ERR_PTR(-ENOMEM);
1243 }
1244
1245 dprintk("RPC: created transport %p with %u slots\n", xprt,
1246 xprt->max_reqs);
1247out:
1248 return xprt;
1249}
1250
1251/**
1252 * xprt_destroy - destroy an RPC transport, killing off all requests.
1253 * @xprt: transport to destroy
1254 *
1255 */
1256static void xprt_destroy(struct rpc_xprt *xprt)
1257{
1258 dprintk("RPC: destroying transport %p\n", xprt);
1259 xprt->shutdown = 1;
1260 del_timer_sync(&xprt->timer);
1261
1262 rpc_destroy_wait_queue(&xprt->binding);
1263 rpc_destroy_wait_queue(&xprt->pending);
1264 rpc_destroy_wait_queue(&xprt->sending);
1265 rpc_destroy_wait_queue(&xprt->backlog);
1266 cancel_work_sync(&xprt->task_cleanup);
1267 kfree(xprt->servername);
1268 /*
1269 * Tear down transport state and free the rpc_xprt
1270 */
1271 xprt->ops->destroy(xprt);
1272}
1273
1274/**
1275 * xprt_put - release a reference to an RPC transport.
1276 * @xprt: pointer to the transport
1277 *
1278 */
1279void xprt_put(struct rpc_xprt *xprt)
1280{
1281 if (atomic_dec_and_test(&xprt->count))
1282 xprt_destroy(xprt);
1283}
1284
1285/**
1286 * xprt_get - return a reference to an RPC transport.
1287 * @xprt: pointer to the transport
1288 *
1289 */
1290struct rpc_xprt *xprt_get(struct rpc_xprt *xprt)
1291{
1292 if (atomic_inc_not_zero(&xprt->count))
1293 return xprt;
1294 return NULL;
1295}