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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, it installs a timer that
16 * is run after the packet's timeout has expired.
17 * - When a packet arrives, the data_ready handler walks the list of
18 * pending requests for that transport. If a matching XID is found, the
19 * caller is woken up, and the timer removed.
20 * - When no reply arrives within the timeout interval, the timer is
21 * fired by the kernel and runs xprt_timer(). It either adjusts the
22 * timeout values (minor timeout) or wakes up the caller with a status
23 * of -ETIMEDOUT.
24 * - When the caller receives a notification from RPC that a reply arrived,
25 * it should release the RPC slot, and process the reply.
26 * If the call timed out, it may choose to retry the operation by
27 * adjusting the initial timeout value, and simply calling rpc_call
28 * again.
29 *
30 * Support for async RPC is done through a set of RPC-specific scheduling
31 * primitives that `transparently' work for processes as well as async
32 * tasks that rely on callbacks.
33 *
34 * Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de>
35 *
36 * Transport switch API copyright (C) 2005, Chuck Lever <cel@netapp.com>
37 */
38
39 #include <linux/module.h>
40
41 #include <linux/types.h>
42 #include <linux/interrupt.h>
43 #include <linux/workqueue.h>
44 #include <linux/random.h>
45
46 #include <linux/sunrpc/clnt.h>
47
48 /*
49 * Local variables
50 */
51
52 #ifdef RPC_DEBUG
53 # undef RPC_DEBUG_DATA
54 # define RPCDBG_FACILITY RPCDBG_XPRT
55 #endif
56
57 /*
58 * Local functions
59 */
60 static void xprt_request_init(struct rpc_task *, struct rpc_xprt *);
61 static inline void do_xprt_reserve(struct rpc_task *);
62 static void xprt_connect_status(struct rpc_task *task);
63 static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
64
65 static int xprt_clear_backlog(struct rpc_xprt *xprt);
66
67 /*
68 * Serialize write access to transports, in order to prevent different
69 * requests from interfering with each other.
70 * Also prevents transport connects from colliding with writes.
71 */
72 static int
73 __xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
74 {
75 struct rpc_rqst *req = task->tk_rqstp;
76
77 if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
78 if (task == xprt->snd_task)
79 return 1;
80 goto out_sleep;
81 }
82 if (xprt->nocong || __xprt_get_cong(xprt, task)) {
83 xprt->snd_task = task;
84 if (req) {
85 req->rq_bytes_sent = 0;
86 req->rq_ntrans++;
87 }
88 return 1;
89 }
90 smp_mb__before_clear_bit();
91 clear_bit(XPRT_LOCKED, &xprt->state);
92 smp_mb__after_clear_bit();
93 out_sleep:
94 dprintk("RPC: %4d failed to lock transport %p\n", task->tk_pid, xprt);
95 task->tk_timeout = 0;
96 task->tk_status = -EAGAIN;
97 if (req && req->rq_ntrans)
98 rpc_sleep_on(&xprt->resend, task, NULL, NULL);
99 else
100 rpc_sleep_on(&xprt->sending, task, NULL, NULL);
101 return 0;
102 }
103
104 static inline int
105 xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
106 {
107 int retval;
108
109 spin_lock_bh(&xprt->transport_lock);
110 retval = __xprt_lock_write(xprt, task);
111 spin_unlock_bh(&xprt->transport_lock);
112 return retval;
113 }
114
115
116 static void
117 __xprt_lock_write_next(struct rpc_xprt *xprt)
118 {
119 struct rpc_task *task;
120
121 if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
122 return;
123 if (!xprt->nocong && RPCXPRT_CONGESTED(xprt))
124 goto out_unlock;
125 task = rpc_wake_up_next(&xprt->resend);
126 if (!task) {
127 task = rpc_wake_up_next(&xprt->sending);
128 if (!task)
129 goto out_unlock;
130 }
131 if (xprt->nocong || __xprt_get_cong(xprt, task)) {
132 struct rpc_rqst *req = task->tk_rqstp;
133 xprt->snd_task = task;
134 if (req) {
135 req->rq_bytes_sent = 0;
136 req->rq_ntrans++;
137 }
138 return;
139 }
140 out_unlock:
141 smp_mb__before_clear_bit();
142 clear_bit(XPRT_LOCKED, &xprt->state);
143 smp_mb__after_clear_bit();
144 }
145
146 /*
147 * Releases the transport for use by other requests.
148 */
149 static void
150 __xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
151 {
152 if (xprt->snd_task == task) {
153 xprt->snd_task = NULL;
154 smp_mb__before_clear_bit();
155 clear_bit(XPRT_LOCKED, &xprt->state);
156 smp_mb__after_clear_bit();
157 __xprt_lock_write_next(xprt);
158 }
159 }
160
161 static inline void
162 xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
163 {
164 spin_lock_bh(&xprt->transport_lock);
165 __xprt_release_write(xprt, task);
166 spin_unlock_bh(&xprt->transport_lock);
167 }
168
169 /*
170 * Van Jacobson congestion avoidance. Check if the congestion window
171 * overflowed. Put the task to sleep if this is the case.
172 */
173 static int
174 __xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task)
175 {
176 struct rpc_rqst *req = task->tk_rqstp;
177
178 if (req->rq_cong)
179 return 1;
180 dprintk("RPC: %4d xprt_cwnd_limited cong = %ld cwnd = %ld\n",
181 task->tk_pid, xprt->cong, xprt->cwnd);
182 if (RPCXPRT_CONGESTED(xprt))
183 return 0;
184 req->rq_cong = 1;
185 xprt->cong += RPC_CWNDSCALE;
186 return 1;
187 }
188
189 /*
190 * Adjust the congestion window, and wake up the next task
191 * that has been sleeping due to congestion
192 */
193 static void
194 __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
195 {
196 if (!req->rq_cong)
197 return;
198 req->rq_cong = 0;
199 xprt->cong -= RPC_CWNDSCALE;
200 __xprt_lock_write_next(xprt);
201 }
202
203 /*
204 * Adjust RPC congestion window
205 * We use a time-smoothed congestion estimator to avoid heavy oscillation.
206 */
207 static void
208 xprt_adjust_cwnd(struct rpc_xprt *xprt, int result)
209 {
210 unsigned long cwnd;
211
212 cwnd = xprt->cwnd;
213 if (result >= 0 && cwnd <= xprt->cong) {
214 /* The (cwnd >> 1) term makes sure
215 * the result gets rounded properly. */
216 cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd;
217 if (cwnd > RPC_MAXCWND(xprt))
218 cwnd = RPC_MAXCWND(xprt);
219 __xprt_lock_write_next(xprt);
220 } else if (result == -ETIMEDOUT) {
221 cwnd >>= 1;
222 if (cwnd < RPC_CWNDSCALE)
223 cwnd = RPC_CWNDSCALE;
224 }
225 dprintk("RPC: cong %ld, cwnd was %ld, now %ld\n",
226 xprt->cong, xprt->cwnd, cwnd);
227 xprt->cwnd = cwnd;
228 }
229
230 /**
231 * xprt_wake_pending_tasks - wake all tasks on a transport's pending queue
232 * @xprt: transport with waiting tasks
233 * @status: result code to plant in each task before waking it
234 *
235 */
236 void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status)
237 {
238 if (status < 0)
239 rpc_wake_up_status(&xprt->pending, status);
240 else
241 rpc_wake_up(&xprt->pending);
242 }
243
244 /**
245 * xprt_wait_for_buffer_space - wait for transport output buffer to clear
246 * @task: task to be put to sleep
247 *
248 */
249 void xprt_wait_for_buffer_space(struct rpc_task *task)
250 {
251 struct rpc_rqst *req = task->tk_rqstp;
252 struct rpc_xprt *xprt = req->rq_xprt;
253
254 task->tk_timeout = req->rq_timeout;
255 rpc_sleep_on(&xprt->pending, task, NULL, NULL);
256 }
257
258 /**
259 * xprt_write_space - wake the task waiting for transport output buffer space
260 * @xprt: transport with waiting tasks
261 *
262 * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
263 */
264 void xprt_write_space(struct rpc_xprt *xprt)
265 {
266 if (unlikely(xprt->shutdown))
267 return;
268
269 spin_lock_bh(&xprt->transport_lock);
270 if (xprt->snd_task) {
271 dprintk("RPC: write space: waking waiting task on xprt %p\n",
272 xprt);
273 rpc_wake_up_task(xprt->snd_task);
274 }
275 spin_unlock_bh(&xprt->transport_lock);
276 }
277
278 static void xprt_reset_majortimeo(struct rpc_rqst *req)
279 {
280 struct rpc_timeout *to = &req->rq_xprt->timeout;
281
282 req->rq_majortimeo = req->rq_timeout;
283 if (to->to_exponential)
284 req->rq_majortimeo <<= to->to_retries;
285 else
286 req->rq_majortimeo += to->to_increment * to->to_retries;
287 if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0)
288 req->rq_majortimeo = to->to_maxval;
289 req->rq_majortimeo += jiffies;
290 }
291
292 /**
293 * xprt_adjust_timeout - adjust timeout values for next retransmit
294 * @req: RPC request containing parameters to use for the adjustment
295 *
296 */
297 int xprt_adjust_timeout(struct rpc_rqst *req)
298 {
299 struct rpc_xprt *xprt = req->rq_xprt;
300 struct rpc_timeout *to = &xprt->timeout;
301 int status = 0;
302
303 if (time_before(jiffies, req->rq_majortimeo)) {
304 if (to->to_exponential)
305 req->rq_timeout <<= 1;
306 else
307 req->rq_timeout += to->to_increment;
308 if (to->to_maxval && req->rq_timeout >= to->to_maxval)
309 req->rq_timeout = to->to_maxval;
310 req->rq_retries++;
311 pprintk("RPC: %lu retrans\n", jiffies);
312 } else {
313 req->rq_timeout = to->to_initval;
314 req->rq_retries = 0;
315 xprt_reset_majortimeo(req);
316 /* Reset the RTT counters == "slow start" */
317 spin_lock_bh(&xprt->transport_lock);
318 rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval);
319 spin_unlock_bh(&xprt->transport_lock);
320 pprintk("RPC: %lu timeout\n", jiffies);
321 status = -ETIMEDOUT;
322 }
323
324 if (req->rq_timeout == 0) {
325 printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n");
326 req->rq_timeout = 5 * HZ;
327 }
328 return status;
329 }
330
331 static void xprt_autoclose(void *args)
332 {
333 struct rpc_xprt *xprt = (struct rpc_xprt *)args;
334
335 xprt_disconnect(xprt);
336 xprt->ops->close(xprt);
337 xprt_release_write(xprt, NULL);
338 }
339
340 /**
341 * xprt_disconnect - mark a transport as disconnected
342 * @xprt: transport to flag for disconnect
343 *
344 */
345 void xprt_disconnect(struct rpc_xprt *xprt)
346 {
347 dprintk("RPC: disconnected transport %p\n", xprt);
348 spin_lock_bh(&xprt->transport_lock);
349 xprt_clear_connected(xprt);
350 xprt_wake_pending_tasks(xprt, -ENOTCONN);
351 spin_unlock_bh(&xprt->transport_lock);
352 }
353
354 static void
355 xprt_init_autodisconnect(unsigned long data)
356 {
357 struct rpc_xprt *xprt = (struct rpc_xprt *)data;
358
359 spin_lock(&xprt->transport_lock);
360 if (!list_empty(&xprt->recv) || xprt->shutdown)
361 goto out_abort;
362 if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
363 goto out_abort;
364 spin_unlock(&xprt->transport_lock);
365 if (xprt_connecting(xprt))
366 xprt_release_write(xprt, NULL);
367 else
368 schedule_work(&xprt->task_cleanup);
369 return;
370 out_abort:
371 spin_unlock(&xprt->transport_lock);
372 }
373
374 /**
375 * xprt_connect - schedule a transport connect operation
376 * @task: RPC task that is requesting the connect
377 *
378 */
379 void xprt_connect(struct rpc_task *task)
380 {
381 struct rpc_xprt *xprt = task->tk_xprt;
382
383 dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task->tk_pid,
384 xprt, (xprt_connected(xprt) ? "is" : "is not"));
385
386 if (xprt->shutdown) {
387 task->tk_status = -EIO;
388 return;
389 }
390 if (!xprt->addr.sin_port) {
391 task->tk_status = -EIO;
392 return;
393 }
394 if (!xprt_lock_write(xprt, task))
395 return;
396 if (xprt_connected(xprt))
397 xprt_release_write(xprt, task);
398 else {
399 if (task->tk_rqstp)
400 task->tk_rqstp->rq_bytes_sent = 0;
401
402 task->tk_timeout = RPC_CONNECT_TIMEOUT;
403 rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL);
404 xprt->ops->connect(task);
405 }
406 return;
407 }
408
409 static void xprt_connect_status(struct rpc_task *task)
410 {
411 struct rpc_xprt *xprt = task->tk_xprt;
412
413 if (task->tk_status >= 0) {
414 dprintk("RPC: %4d xprt_connect_status: connection established\n",
415 task->tk_pid);
416 return;
417 }
418
419 switch (task->tk_status) {
420 case -ECONNREFUSED:
421 case -ECONNRESET:
422 dprintk("RPC: %4d xprt_connect_status: server %s refused connection\n",
423 task->tk_pid, task->tk_client->cl_server);
424 break;
425 case -ENOTCONN:
426 dprintk("RPC: %4d xprt_connect_status: connection broken\n",
427 task->tk_pid);
428 break;
429 case -ETIMEDOUT:
430 dprintk("RPC: %4d xprt_connect_status: connect attempt timed out\n",
431 task->tk_pid);
432 break;
433 default:
434 dprintk("RPC: %4d xprt_connect_status: error %d connecting to server %s\n",
435 task->tk_pid, -task->tk_status, task->tk_client->cl_server);
436 xprt_release_write(xprt, task);
437 task->tk_status = -EIO;
438 return;
439 }
440
441 /* if soft mounted, just cause this RPC to fail */
442 if (RPC_IS_SOFT(task)) {
443 xprt_release_write(xprt, task);
444 task->tk_status = -EIO;
445 }
446 }
447
448 /**
449 * xprt_lookup_rqst - find an RPC request corresponding to an XID
450 * @xprt: transport on which the original request was transmitted
451 * @xid: RPC XID of incoming reply
452 *
453 */
454 struct rpc_rqst *xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid)
455 {
456 struct list_head *pos;
457 struct rpc_rqst *req = NULL;
458
459 list_for_each(pos, &xprt->recv) {
460 struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list);
461 if (entry->rq_xid == xid) {
462 req = entry;
463 break;
464 }
465 }
466 return req;
467 }
468
469 /**
470 * xprt_complete_rqst - called when reply processing is complete
471 * @xprt: controlling transport
472 * @req: RPC request that just completed
473 * @copied: actual number of bytes received from the transport
474 *
475 */
476 void xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied)
477 {
478 struct rpc_task *task = req->rq_task;
479 struct rpc_clnt *clnt = task->tk_client;
480
481 /* Adjust congestion window */
482 if (!xprt->nocong) {
483 unsigned timer = task->tk_msg.rpc_proc->p_timer;
484 xprt_adjust_cwnd(xprt, copied);
485 __xprt_put_cong(xprt, req);
486 if (timer) {
487 if (req->rq_ntrans == 1)
488 rpc_update_rtt(clnt->cl_rtt, timer,
489 (long)jiffies - req->rq_xtime);
490 rpc_set_timeo(clnt->cl_rtt, timer, req->rq_ntrans - 1);
491 }
492 }
493
494 #ifdef RPC_PROFILE
495 /* Profile only reads for now */
496 if (copied > 1024) {
497 static unsigned long nextstat;
498 static unsigned long pkt_rtt, pkt_len, pkt_cnt;
499
500 pkt_cnt++;
501 pkt_len += req->rq_slen + copied;
502 pkt_rtt += jiffies - req->rq_xtime;
503 if (time_before(nextstat, jiffies)) {
504 printk("RPC: %lu %ld cwnd\n", jiffies, xprt->cwnd);
505 printk("RPC: %ld %ld %ld %ld stat\n",
506 jiffies, pkt_cnt, pkt_len, pkt_rtt);
507 pkt_rtt = pkt_len = pkt_cnt = 0;
508 nextstat = jiffies + 5 * HZ;
509 }
510 }
511 #endif
512
513 dprintk("RPC: %4d has input (%d bytes)\n", task->tk_pid, copied);
514 list_del_init(&req->rq_list);
515 req->rq_received = req->rq_private_buf.len = copied;
516
517 /* ... and wake up the process. */
518 rpc_wake_up_task(task);
519 return;
520 }
521
522 /*
523 * RPC receive timeout handler.
524 */
525 static void
526 xprt_timer(struct rpc_task *task)
527 {
528 struct rpc_rqst *req = task->tk_rqstp;
529 struct rpc_xprt *xprt = req->rq_xprt;
530
531 spin_lock(&xprt->transport_lock);
532 if (req->rq_received)
533 goto out;
534
535 xprt_adjust_cwnd(req->rq_xprt, -ETIMEDOUT);
536 __xprt_put_cong(xprt, req);
537
538 dprintk("RPC: %4d xprt_timer (%s request)\n",
539 task->tk_pid, req ? "pending" : "backlogged");
540
541 task->tk_status = -ETIMEDOUT;
542 out:
543 task->tk_timeout = 0;
544 rpc_wake_up_task(task);
545 spin_unlock(&xprt->transport_lock);
546 }
547
548 /**
549 * xprt_prepare_transmit - reserve the transport before sending a request
550 * @task: RPC task about to send a request
551 *
552 */
553 int xprt_prepare_transmit(struct rpc_task *task)
554 {
555 struct rpc_rqst *req = task->tk_rqstp;
556 struct rpc_xprt *xprt = req->rq_xprt;
557 int err = 0;
558
559 dprintk("RPC: %4d xprt_prepare_transmit\n", task->tk_pid);
560
561 if (xprt->shutdown)
562 return -EIO;
563
564 spin_lock_bh(&xprt->transport_lock);
565 if (req->rq_received && !req->rq_bytes_sent) {
566 err = req->rq_received;
567 goto out_unlock;
568 }
569 if (!__xprt_lock_write(xprt, task)) {
570 err = -EAGAIN;
571 goto out_unlock;
572 }
573
574 if (!xprt_connected(xprt)) {
575 err = -ENOTCONN;
576 goto out_unlock;
577 }
578 out_unlock:
579 spin_unlock_bh(&xprt->transport_lock);
580 return err;
581 }
582
583 /**
584 * xprt_transmit - send an RPC request on a transport
585 * @task: controlling RPC task
586 *
587 * We have to copy the iovec because sendmsg fiddles with its contents.
588 */
589 void xprt_transmit(struct rpc_task *task)
590 {
591 struct rpc_clnt *clnt = task->tk_client;
592 struct rpc_rqst *req = task->tk_rqstp;
593 struct rpc_xprt *xprt = req->rq_xprt;
594 int status;
595
596 dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
597
598 smp_rmb();
599 if (!req->rq_received) {
600 if (list_empty(&req->rq_list)) {
601 spin_lock_bh(&xprt->transport_lock);
602 /* Update the softirq receive buffer */
603 memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
604 sizeof(req->rq_private_buf));
605 /* Add request to the receive list */
606 list_add_tail(&req->rq_list, &xprt->recv);
607 spin_unlock_bh(&xprt->transport_lock);
608 xprt_reset_majortimeo(req);
609 /* Turn off autodisconnect */
610 del_singleshot_timer_sync(&xprt->timer);
611 }
612 } else if (!req->rq_bytes_sent)
613 return;
614
615 status = xprt->ops->send_request(task);
616 if (!status)
617 goto out_receive;
618
619 /* Note: at this point, task->tk_sleeping has not yet been set,
620 * hence there is no danger of the waking up task being put on
621 * schedq, and being picked up by a parallel run of rpciod().
622 */
623 task->tk_status = status;
624
625 switch (status) {
626 case -ECONNREFUSED:
627 task->tk_timeout = RPC_REESTABLISH_TIMEOUT;
628 rpc_sleep_on(&xprt->sending, task, NULL, NULL);
629 case -EAGAIN:
630 case -ENOTCONN:
631 return;
632 default:
633 if (xprt->stream)
634 xprt_disconnect(xprt);
635 }
636 xprt_release_write(xprt, task);
637 return;
638 out_receive:
639 dprintk("RPC: %4d xmit complete\n", task->tk_pid);
640 /* Set the task's receive timeout value */
641 spin_lock_bh(&xprt->transport_lock);
642 if (!xprt->nocong) {
643 int timer = task->tk_msg.rpc_proc->p_timer;
644 task->tk_timeout = rpc_calc_rto(clnt->cl_rtt, timer);
645 task->tk_timeout <<= rpc_ntimeo(clnt->cl_rtt, timer) + req->rq_retries;
646 if (task->tk_timeout > xprt->timeout.to_maxval || task->tk_timeout == 0)
647 task->tk_timeout = xprt->timeout.to_maxval;
648 } else
649 task->tk_timeout = req->rq_timeout;
650 /* Don't race with disconnect */
651 if (!xprt_connected(xprt))
652 task->tk_status = -ENOTCONN;
653 else if (!req->rq_received)
654 rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);
655 __xprt_release_write(xprt, task);
656 spin_unlock_bh(&xprt->transport_lock);
657 }
658
659 static inline void do_xprt_reserve(struct rpc_task *task)
660 {
661 struct rpc_xprt *xprt = task->tk_xprt;
662
663 task->tk_status = 0;
664 if (task->tk_rqstp)
665 return;
666 if (!list_empty(&xprt->free)) {
667 struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
668 list_del_init(&req->rq_list);
669 task->tk_rqstp = req;
670 xprt_request_init(task, xprt);
671 return;
672 }
673 dprintk("RPC: waiting for request slot\n");
674 task->tk_status = -EAGAIN;
675 task->tk_timeout = 0;
676 rpc_sleep_on(&xprt->backlog, task, NULL, NULL);
677 }
678
679 /**
680 * xprt_reserve - allocate an RPC request slot
681 * @task: RPC task requesting a slot allocation
682 *
683 * If no more slots are available, place the task on the transport's
684 * backlog queue.
685 */
686 void xprt_reserve(struct rpc_task *task)
687 {
688 struct rpc_xprt *xprt = task->tk_xprt;
689
690 task->tk_status = -EIO;
691 if (!xprt->shutdown) {
692 spin_lock(&xprt->reserve_lock);
693 do_xprt_reserve(task);
694 spin_unlock(&xprt->reserve_lock);
695 }
696 }
697
698 static inline u32 xprt_alloc_xid(struct rpc_xprt *xprt)
699 {
700 return xprt->xid++;
701 }
702
703 static inline void xprt_init_xid(struct rpc_xprt *xprt)
704 {
705 get_random_bytes(&xprt->xid, sizeof(xprt->xid));
706 }
707
708 static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
709 {
710 struct rpc_rqst *req = task->tk_rqstp;
711
712 req->rq_timeout = xprt->timeout.to_initval;
713 req->rq_task = task;
714 req->rq_xprt = xprt;
715 req->rq_xid = xprt_alloc_xid(xprt);
716 dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
717 req, ntohl(req->rq_xid));
718 }
719
720 /**
721 * xprt_release - release an RPC request slot
722 * @task: task which is finished with the slot
723 *
724 */
725 void xprt_release(struct rpc_task *task)
726 {
727 struct rpc_xprt *xprt = task->tk_xprt;
728 struct rpc_rqst *req;
729
730 if (!(req = task->tk_rqstp))
731 return;
732 spin_lock_bh(&xprt->transport_lock);
733 __xprt_release_write(xprt, task);
734 __xprt_put_cong(xprt, req);
735 if (!list_empty(&req->rq_list))
736 list_del(&req->rq_list);
737 xprt->last_used = jiffies;
738 if (list_empty(&xprt->recv) && !xprt->shutdown)
739 mod_timer(&xprt->timer,
740 xprt->last_used + RPC_IDLE_DISCONNECT_TIMEOUT);
741 spin_unlock_bh(&xprt->transport_lock);
742 task->tk_rqstp = NULL;
743 memset(req, 0, sizeof(*req)); /* mark unused */
744
745 dprintk("RPC: %4d release request %p\n", task->tk_pid, req);
746
747 spin_lock(&xprt->reserve_lock);
748 list_add(&req->rq_list, &xprt->free);
749 xprt_clear_backlog(xprt);
750 spin_unlock(&xprt->reserve_lock);
751 }
752
753 /**
754 * xprt_set_timeout - set constant RPC timeout
755 * @to: RPC timeout parameters to set up
756 * @retr: number of retries
757 * @incr: amount of increase after each retry
758 *
759 */
760 void xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr)
761 {
762 to->to_initval =
763 to->to_increment = incr;
764 to->to_maxval = to->to_initval + (incr * retr);
765 to->to_retries = retr;
766 to->to_exponential = 0;
767 }
768
769 static struct rpc_xprt *xprt_setup(int proto, struct sockaddr_in *ap, struct rpc_timeout *to)
770 {
771 int result;
772 struct rpc_xprt *xprt;
773 struct rpc_rqst *req;
774
775 if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL)
776 return ERR_PTR(-ENOMEM);
777 memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */
778
779 xprt->addr = *ap;
780
781 switch (proto) {
782 case IPPROTO_UDP:
783 result = xs_setup_udp(xprt, to);
784 break;
785 case IPPROTO_TCP:
786 result = xs_setup_tcp(xprt, to);
787 break;
788 default:
789 printk(KERN_ERR "RPC: unrecognized transport protocol: %d\n",
790 proto);
791 result = -EIO;
792 break;
793 }
794 if (result) {
795 kfree(xprt);
796 return ERR_PTR(result);
797 }
798
799 spin_lock_init(&xprt->transport_lock);
800 spin_lock_init(&xprt->reserve_lock);
801 init_waitqueue_head(&xprt->cong_wait);
802
803 INIT_LIST_HEAD(&xprt->free);
804 INIT_LIST_HEAD(&xprt->recv);
805 INIT_WORK(&xprt->task_cleanup, xprt_autoclose, xprt);
806 init_timer(&xprt->timer);
807 xprt->timer.function = xprt_init_autodisconnect;
808 xprt->timer.data = (unsigned long) xprt;
809 xprt->last_used = jiffies;
810
811 rpc_init_wait_queue(&xprt->pending, "xprt_pending");
812 rpc_init_wait_queue(&xprt->sending, "xprt_sending");
813 rpc_init_wait_queue(&xprt->resend, "xprt_resend");
814 rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
815
816 /* initialize free list */
817 for (req = &xprt->slot[xprt->max_reqs-1]; req >= &xprt->slot[0]; req--)
818 list_add(&req->rq_list, &xprt->free);
819
820 xprt_init_xid(xprt);
821
822 dprintk("RPC: created transport %p with %u slots\n", xprt,
823 xprt->max_reqs);
824
825 return xprt;
826 }
827
828 /**
829 * xprt_create_proto - create an RPC client transport
830 * @proto: requested transport protocol
831 * @sap: remote peer's address
832 * @to: timeout parameters for new transport
833 *
834 */
835 struct rpc_xprt *xprt_create_proto(int proto, struct sockaddr_in *sap, struct rpc_timeout *to)
836 {
837 struct rpc_xprt *xprt;
838
839 xprt = xprt_setup(proto, sap, to);
840 if (IS_ERR(xprt))
841 dprintk("RPC: xprt_create_proto failed\n");
842 else
843 dprintk("RPC: xprt_create_proto created xprt %p\n", xprt);
844 return xprt;
845 }
846
847 static void xprt_shutdown(struct rpc_xprt *xprt)
848 {
849 xprt->shutdown = 1;
850 rpc_wake_up(&xprt->sending);
851 rpc_wake_up(&xprt->resend);
852 xprt_wake_pending_tasks(xprt, -EIO);
853 rpc_wake_up(&xprt->backlog);
854 wake_up(&xprt->cong_wait);
855 del_timer_sync(&xprt->timer);
856 }
857
858 static int xprt_clear_backlog(struct rpc_xprt *xprt) {
859 rpc_wake_up_next(&xprt->backlog);
860 wake_up(&xprt->cong_wait);
861 return 1;
862 }
863
864 /**
865 * xprt_destroy - destroy an RPC transport, killing off all requests.
866 * @xprt: transport to destroy
867 *
868 */
869 int xprt_destroy(struct rpc_xprt *xprt)
870 {
871 dprintk("RPC: destroying transport %p\n", xprt);
872 xprt_shutdown(xprt);
873 xprt->ops->destroy(xprt);
874 kfree(xprt);
875
876 return 0;
877 }