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PM: Move definition of struct pm_ops to suspend.h
[linux-2.6/verdex.git] / net / 9p / mux.c
blobf14014793bedb2fcbee870e84a6b0bde10be88fb
1 /*
2 * net/9p/mux.c
3 *
4 * Protocol Multiplexer
5 *
6 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
7 * Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2
11 * as published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to:
20 * Free Software Foundation
21 * 51 Franklin Street, Fifth Floor
22 * Boston, MA 02111-1301 USA
23 *
24 */
25
26 #include <linux/module.h>
27 #include <linux/errno.h>
28 #include <linux/fs.h>
29 #include <linux/poll.h>
30 #include <linux/kthread.h>
31 #include <linux/idr.h>
32 #include <linux/mutex.h>
33 #include <net/9p/9p.h>
34 #include <linux/parser.h>
35 #include <net/9p/transport.h>
36 #include <net/9p/conn.h>
37
38 #define ERREQFLUSH 1
39 #define SCHED_TIMEOUT 10
40 #define MAXPOLLWADDR 2
41
42 enum {
43 Rworksched = 1, /* read work scheduled or running */
44 Rpending = 2, /* can read */
45 Wworksched = 4, /* write work scheduled or running */
46 Wpending = 8, /* can write */
47 };
48
49 enum {
50 None,
51 Flushing,
52 Flushed,
53 };
54
55 struct p9_mux_poll_task;
56
57 struct p9_req {
58 spinlock_t lock; /* protect request structure */
59 int tag;
60 struct p9_fcall *tcall;
61 struct p9_fcall *rcall;
62 int err;
63 p9_conn_req_callback cb;
64 void *cba;
65 int flush;
66 struct list_head req_list;
67 };
68
69 struct p9_conn {
70 spinlock_t lock; /* protect lock structure */
71 struct list_head mux_list;
72 struct p9_mux_poll_task *poll_task;
73 int msize;
74 unsigned char *extended;
75 struct p9_trans *trans;
76 struct p9_idpool *tagpool;
77 int err;
78 wait_queue_head_t equeue;
79 struct list_head req_list;
80 struct list_head unsent_req_list;
81 struct p9_fcall *rcall;
82 int rpos;
83 char *rbuf;
84 int wpos;
85 int wsize;
86 char *wbuf;
87 wait_queue_t poll_wait[MAXPOLLWADDR];
88 wait_queue_head_t *poll_waddr[MAXPOLLWADDR];
89 poll_table pt;
90 struct work_struct rq;
91 struct work_struct wq;
92 unsigned long wsched;
93 };
94
95 struct p9_mux_poll_task {
96 struct task_struct *task;
97 struct list_head mux_list;
98 int muxnum;
99 };
100
101 struct p9_mux_rpc {
102 struct p9_conn *m;
103 int err;
104 struct p9_fcall *tcall;
105 struct p9_fcall *rcall;
106 wait_queue_head_t wqueue;
107 };
108
109 static int p9_poll_proc(void *);
110 static void p9_read_work(struct work_struct *work);
111 static void p9_write_work(struct work_struct *work);
112 static void p9_pollwait(struct file *filp, wait_queue_head_t *wait_address,
113 poll_table * p);
114 static u16 p9_mux_get_tag(struct p9_conn *);
115 static void p9_mux_put_tag(struct p9_conn *, u16);
116
117 static DEFINE_MUTEX(p9_mux_task_lock);
118 static struct workqueue_struct *p9_mux_wq;
119
120 static int p9_mux_num;
121 static int p9_mux_poll_task_num;
122 static struct p9_mux_poll_task p9_mux_poll_tasks[100];
123
124 int p9_mux_global_init(void)
125 {
126 int i;
127
128 for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++)
129 p9_mux_poll_tasks[i].task = NULL;
130
131 p9_mux_wq = create_workqueue("v9fs");
132 if (!p9_mux_wq) {
133 printk(KERN_WARNING "v9fs: mux: creating workqueue failed\n");
134 return -ENOMEM;
135 }
136
137 return 0;
138 }
139
140 void p9_mux_global_exit(void)
141 {
142 destroy_workqueue(p9_mux_wq);
143 }
144
145 /**
146 * p9_mux_calc_poll_procs - calculates the number of polling procs
147 * based on the number of mounted v9fs filesystems.
148 *
149 * The current implementation returns sqrt of the number of mounts.
150 */
151 static int p9_mux_calc_poll_procs(int muxnum)
152 {
153 int n;
154
155 if (p9_mux_poll_task_num)
156 n = muxnum / p9_mux_poll_task_num +
157 (muxnum % p9_mux_poll_task_num ? 1 : 0);
158 else
159 n = 1;
160
161 if (n > ARRAY_SIZE(p9_mux_poll_tasks))
162 n = ARRAY_SIZE(p9_mux_poll_tasks);
163
164 return n;
165 }
166
167 static int p9_mux_poll_start(struct p9_conn *m)
168 {
169 int i, n;
170 struct p9_mux_poll_task *vpt, *vptlast;
171 struct task_struct *pproc;
172
173 P9_DPRINTK(P9_DEBUG_MUX, "mux %p muxnum %d procnum %d\n", m, p9_mux_num,
174 p9_mux_poll_task_num);
175 mutex_lock(&p9_mux_task_lock);
176
177 n = p9_mux_calc_poll_procs(p9_mux_num + 1);
178 if (n > p9_mux_poll_task_num) {
179 for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++) {
180 if (p9_mux_poll_tasks[i].task == NULL) {
181 vpt = &p9_mux_poll_tasks[i];
182 P9_DPRINTK(P9_DEBUG_MUX, "create proc %p\n",
183 vpt);
184 pproc = kthread_create(p9_poll_proc, vpt,
185 "v9fs-poll");
186
187 if (!IS_ERR(pproc)) {
188 vpt->task = pproc;
189 INIT_LIST_HEAD(&vpt->mux_list);
190 vpt->muxnum = 0;
191 p9_mux_poll_task_num++;
192 wake_up_process(vpt->task);
193 }
194 break;
195 }
196 }
197
198 if (i >= ARRAY_SIZE(p9_mux_poll_tasks))
199 P9_DPRINTK(P9_DEBUG_ERROR,
200 "warning: no free poll slots\n");
201 }
202
203 n = (p9_mux_num + 1) / p9_mux_poll_task_num +
204 ((p9_mux_num + 1) % p9_mux_poll_task_num ? 1 : 0);
205
206 vptlast = NULL;
207 for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++) {
208 vpt = &p9_mux_poll_tasks[i];
209 if (vpt->task != NULL) {
210 vptlast = vpt;
211 if (vpt->muxnum < n) {
212 P9_DPRINTK(P9_DEBUG_MUX, "put in proc %d\n", i);
213 list_add(&m->mux_list, &vpt->mux_list);
214 vpt->muxnum++;
215 m->poll_task = vpt;
216 memset(&m->poll_waddr, 0,
217 sizeof(m->poll_waddr));
218 init_poll_funcptr(&m->pt, p9_pollwait);
219 break;
220 }
221 }
222 }
223
224 if (i >= ARRAY_SIZE(p9_mux_poll_tasks)) {
225 if (vptlast == NULL)
226 return -ENOMEM;
227
228 P9_DPRINTK(P9_DEBUG_MUX, "put in proc %d\n", i);
229 list_add(&m->mux_list, &vptlast->mux_list);
230 vptlast->muxnum++;
231 m->poll_task = vptlast;
232 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
233 init_poll_funcptr(&m->pt, p9_pollwait);
234 }
235
236 p9_mux_num++;
237 mutex_unlock(&p9_mux_task_lock);
238
239 return 0;
240 }
241
242 static void p9_mux_poll_stop(struct p9_conn *m)
243 {
244 int i;
245 struct p9_mux_poll_task *vpt;
246
247 mutex_lock(&p9_mux_task_lock);
248 vpt = m->poll_task;
249 list_del(&m->mux_list);
250 for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
251 if (m->poll_waddr[i] != NULL) {
252 remove_wait_queue(m->poll_waddr[i], &m->poll_wait[i]);
253 m->poll_waddr[i] = NULL;
254 }
255 }
256 vpt->muxnum--;
257 if (!vpt->muxnum) {
258 P9_DPRINTK(P9_DEBUG_MUX, "destroy proc %p\n", vpt);
259 kthread_stop(vpt->task);
260 vpt->task = NULL;
261 p9_mux_poll_task_num--;
262 }
263 p9_mux_num--;
264 mutex_unlock(&p9_mux_task_lock);
265 }
266
267 /**
268 * p9_conn_create - allocate and initialize the per-session mux data
269 * Creates the polling task if this is the first session.
270 *
271 * @trans - transport structure
272 * @msize - maximum message size
273 * @extended - pointer to the extended flag
274 */
275 struct p9_conn *p9_conn_create(struct p9_trans *trans, int msize,
276 unsigned char *extended)
277 {
278 int i, n;
279 struct p9_conn *m, *mtmp;
280
281 P9_DPRINTK(P9_DEBUG_MUX, "transport %p msize %d\n", trans, msize);
282 m = kmalloc(sizeof(struct p9_conn), GFP_KERNEL);
283 if (!m)
284 return ERR_PTR(-ENOMEM);
285
286 spin_lock_init(&m->lock);
287 INIT_LIST_HEAD(&m->mux_list);
288 m->msize = msize;
289 m->extended = extended;
290 m->trans = trans;
291 m->tagpool = p9_idpool_create();
292 if (IS_ERR(m->tagpool)) {
293 mtmp = ERR_PTR(-ENOMEM);
294 kfree(m);
295 return mtmp;
296 }
297
298 m->err = 0;
299 init_waitqueue_head(&m->equeue);
300 INIT_LIST_HEAD(&m->req_list);
301 INIT_LIST_HEAD(&m->unsent_req_list);
302 m->rcall = NULL;
303 m->rpos = 0;
304 m->rbuf = NULL;
305 m->wpos = m->wsize = 0;
306 m->wbuf = NULL;
307 INIT_WORK(&m->rq, p9_read_work);
308 INIT_WORK(&m->wq, p9_write_work);
309 m->wsched = 0;
310 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
311 m->poll_task = NULL;
312 n = p9_mux_poll_start(m);
313 if (n) {
314 kfree(m);
315 return ERR_PTR(n);
316 }
317
318 n = trans->poll(trans, &m->pt);
319 if (n & POLLIN) {
320 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
321 set_bit(Rpending, &m->wsched);
322 }
323
324 if (n & POLLOUT) {
325 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
326 set_bit(Wpending, &m->wsched);
327 }
328
329 for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
330 if (IS_ERR(m->poll_waddr[i])) {
331 p9_mux_poll_stop(m);
332 mtmp = (void *)m->poll_waddr; /* the error code */
333 kfree(m);
334 m = mtmp;
335 break;
336 }
337 }
338
339 return m;
340 }
341 EXPORT_SYMBOL(p9_conn_create);
342
343 /**
344 * p9_mux_destroy - cancels all pending requests and frees mux resources
345 */
346 void p9_conn_destroy(struct p9_conn *m)
347 {
348 P9_DPRINTK(P9_DEBUG_MUX, "mux %p prev %p next %p\n", m,
349 m->mux_list.prev, m->mux_list.next);
350 p9_conn_cancel(m, -ECONNRESET);
351
352 if (!list_empty(&m->req_list)) {
353 /* wait until all processes waiting on this session exit */
354 P9_DPRINTK(P9_DEBUG_MUX,
355 "mux %p waiting for empty request queue\n", m);
356 wait_event_timeout(m->equeue, (list_empty(&m->req_list)), 5000);
357 P9_DPRINTK(P9_DEBUG_MUX, "mux %p request queue empty: %d\n", m,
358 list_empty(&m->req_list));
359 }
360
361 p9_mux_poll_stop(m);
362 m->trans = NULL;
363 p9_idpool_destroy(m->tagpool);
364 kfree(m);
365 }
366 EXPORT_SYMBOL(p9_conn_destroy);
367
368 /**
369 * p9_pollwait - called by files poll operation to add v9fs-poll task
370 * to files wait queue
371 */
372 static void
373 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address,
374 poll_table * p)
375 {
376 int i;
377 struct p9_conn *m;
378
379 m = container_of(p, struct p9_conn, pt);
380 for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++)
381 if (m->poll_waddr[i] == NULL)
382 break;
383
384 if (i >= ARRAY_SIZE(m->poll_waddr)) {
385 P9_DPRINTK(P9_DEBUG_ERROR, "not enough wait_address slots\n");
386 return;
387 }
388
389 m->poll_waddr[i] = wait_address;
390
391 if (!wait_address) {
392 P9_DPRINTK(P9_DEBUG_ERROR, "no wait_address\n");
393 m->poll_waddr[i] = ERR_PTR(-EIO);
394 return;
395 }
396
397 init_waitqueue_entry(&m->poll_wait[i], m->poll_task->task);
398 add_wait_queue(wait_address, &m->poll_wait[i]);
399 }
400
401 /**
402 * p9_poll_mux - polls a mux and schedules read or write works if necessary
403 */
404 static void p9_poll_mux(struct p9_conn *m)
405 {
406 int n;
407
408 if (m->err < 0)
409 return;
410
411 n = m->trans->poll(m->trans, NULL);
412 if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) {
413 P9_DPRINTK(P9_DEBUG_MUX, "error mux %p err %d\n", m, n);
414 if (n >= 0)
415 n = -ECONNRESET;
416 p9_conn_cancel(m, n);
417 }
418
419 if (n & POLLIN) {
420 set_bit(Rpending, &m->wsched);
421 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
422 if (!test_and_set_bit(Rworksched, &m->wsched)) {
423 P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
424 queue_work(p9_mux_wq, &m->rq);
425 }
426 }
427
428 if (n & POLLOUT) {
429 set_bit(Wpending, &m->wsched);
430 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
431 if ((m->wsize || !list_empty(&m->unsent_req_list))
432 && !test_and_set_bit(Wworksched, &m->wsched)) {
433 P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
434 queue_work(p9_mux_wq, &m->wq);
435 }
436 }
437 }
438
439 /**
440 * p9_poll_proc - polls all v9fs transports for new events and queues
441 * the appropriate work to the work queue
442 */
443 static int p9_poll_proc(void *a)
444 {
445 struct p9_conn *m, *mtmp;
446 struct p9_mux_poll_task *vpt;
447
448 vpt = a;
449 P9_DPRINTK(P9_DEBUG_MUX, "start %p %p\n", current, vpt);
450 while (!kthread_should_stop()) {
451 set_current_state(TASK_INTERRUPTIBLE);
452
453 list_for_each_entry_safe(m, mtmp, &vpt->mux_list, mux_list) {
454 p9_poll_mux(m);
455 }
456
457 P9_DPRINTK(P9_DEBUG_MUX, "sleeping...\n");
458 schedule_timeout(SCHED_TIMEOUT * HZ);
459 }
460
461 __set_current_state(TASK_RUNNING);
462 P9_DPRINTK(P9_DEBUG_MUX, "finish\n");
463 return 0;
464 }
465
466 /**
467 * p9_write_work - called when a transport can send some data
468 */
469 static void p9_write_work(struct work_struct *work)
470 {
471 int n, err;
472 struct p9_conn *m;
473 struct p9_req *req;
474
475 m = container_of(work, struct p9_conn, wq);
476
477 if (m->err < 0) {
478 clear_bit(Wworksched, &m->wsched);
479 return;
480 }
481
482 if (!m->wsize) {
483 if (list_empty(&m->unsent_req_list)) {
484 clear_bit(Wworksched, &m->wsched);
485 return;
486 }
487
488 spin_lock(&m->lock);
489 again:
490 req = list_entry(m->unsent_req_list.next, struct p9_req,
491 req_list);
492 list_move_tail(&req->req_list, &m->req_list);
493 if (req->err == ERREQFLUSH)
494 goto again;
495
496 m->wbuf = req->tcall->sdata;
497 m->wsize = req->tcall->size;
498 m->wpos = 0;
499 spin_unlock(&m->lock);
500 }
501
502 P9_DPRINTK(P9_DEBUG_MUX, "mux %p pos %d size %d\n", m, m->wpos,
503 m->wsize);
504 clear_bit(Wpending, &m->wsched);
505 err = m->trans->write(m->trans, m->wbuf + m->wpos, m->wsize - m->wpos);
506 P9_DPRINTK(P9_DEBUG_MUX, "mux %p sent %d bytes\n", m, err);
507 if (err == -EAGAIN) {
508 clear_bit(Wworksched, &m->wsched);
509 return;
510 }
511
512 if (err < 0)
513 goto error;
514 else if (err == 0) {
515 err = -EREMOTEIO;
516 goto error;
517 }
518
519 m->wpos += err;
520 if (m->wpos == m->wsize)
521 m->wpos = m->wsize = 0;
522
523 if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
524 if (test_and_clear_bit(Wpending, &m->wsched))
525 n = POLLOUT;
526 else
527 n = m->trans->poll(m->trans, NULL);
528
529 if (n & POLLOUT) {
530 P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
531 queue_work(p9_mux_wq, &m->wq);
532 } else
533 clear_bit(Wworksched, &m->wsched);
534 } else
535 clear_bit(Wworksched, &m->wsched);
536
537 return;
538
539 error:
540 p9_conn_cancel(m, err);
541 clear_bit(Wworksched, &m->wsched);
542 }
543
544 static void process_request(struct p9_conn *m, struct p9_req *req)
545 {
546 int ecode;
547 struct p9_str *ename;
548
549 if (!req->err && req->rcall->id == P9_RERROR) {
550 ecode = req->rcall->params.rerror.errno;
551 ename = &req->rcall->params.rerror.error;
552
553 P9_DPRINTK(P9_DEBUG_MUX, "Rerror %.*s\n", ename->len,
554 ename->str);
555
556 if (*m->extended)
557 req->err = -ecode;
558
559 if (!req->err) {
560 req->err = p9_errstr2errno(ename->str, ename->len);
561
562 if (!req->err) { /* string match failed */
563 PRINT_FCALL_ERROR("unknown error", req->rcall);
564 }
565
566 if (!req->err)
567 req->err = -ESERVERFAULT;
568 }
569 } else if (req->tcall && req->rcall->id != req->tcall->id + 1) {
570 P9_DPRINTK(P9_DEBUG_ERROR,
571 "fcall mismatch: expected %d, got %d\n",
572 req->tcall->id + 1, req->rcall->id);
573 if (!req->err)
574 req->err = -EIO;
575 }
576 }
577
578 /**
579 * p9_read_work - called when there is some data to be read from a transport
580 */
581 static void p9_read_work(struct work_struct *work)
582 {
583 int n, err;
584 struct p9_conn *m;
585 struct p9_req *req, *rptr, *rreq;
586 struct p9_fcall *rcall;
587 char *rbuf;
588
589 m = container_of(work, struct p9_conn, rq);
590
591 if (m->err < 0)
592 return;
593
594 rcall = NULL;
595 P9_DPRINTK(P9_DEBUG_MUX, "start mux %p pos %d\n", m, m->rpos);
596
597 if (!m->rcall) {
598 m->rcall =
599 kmalloc(sizeof(struct p9_fcall) + m->msize, GFP_KERNEL);
600 if (!m->rcall) {
601 err = -ENOMEM;
602 goto error;
603 }
604
605 m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
606 m->rpos = 0;
607 }
608
609 clear_bit(Rpending, &m->wsched);
610 err = m->trans->read(m->trans, m->rbuf + m->rpos, m->msize - m->rpos);
611 P9_DPRINTK(P9_DEBUG_MUX, "mux %p got %d bytes\n", m, err);
612 if (err == -EAGAIN) {
613 clear_bit(Rworksched, &m->wsched);
614 return;
615 }
616
617 if (err <= 0)
618 goto error;
619
620 m->rpos += err;
621 while (m->rpos > 4) {
622 n = le32_to_cpu(*(__le32 *) m->rbuf);
623 if (n >= m->msize) {
624 P9_DPRINTK(P9_DEBUG_ERROR,
625 "requested packet size too big: %d\n", n);
626 err = -EIO;
627 goto error;
628 }
629
630 if (m->rpos < n)
631 break;
632
633 err =
634 p9_deserialize_fcall(m->rbuf, n, m->rcall, *m->extended);
635 if (err < 0) {
636 goto error;
637 }
638
639 #ifdef CONFIG_NET_9P_DEBUG
640 if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
641 char buf[150];
642
643 p9_printfcall(buf, sizeof(buf), m->rcall,
644 *m->extended);
645 printk(KERN_NOTICE ">>> %p %s\n", m, buf);
646 }
647 #endif
648
649 rcall = m->rcall;
650 rbuf = m->rbuf;
651 if (m->rpos > n) {
652 m->rcall = kmalloc(sizeof(struct p9_fcall) + m->msize,
653 GFP_KERNEL);
654 if (!m->rcall) {
655 err = -ENOMEM;
656 goto error;
657 }
658
659 m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
660 memmove(m->rbuf, rbuf + n, m->rpos - n);
661 m->rpos -= n;
662 } else {
663 m->rcall = NULL;
664 m->rbuf = NULL;
665 m->rpos = 0;
666 }
667
668 P9_DPRINTK(P9_DEBUG_MUX, "mux %p fcall id %d tag %d\n", m,
669 rcall->id, rcall->tag);
670
671 req = NULL;
672 spin_lock(&m->lock);
673 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
674 if (rreq->tag == rcall->tag) {
675 req = rreq;
676 if (req->flush != Flushing)
677 list_del(&req->req_list);
678 break;
679 }
680 }
681 spin_unlock(&m->lock);
682
683 if (req) {
684 req->rcall = rcall;
685 process_request(m, req);
686
687 if (req->flush != Flushing) {
688 if (req->cb)
689 (*req->cb) (req, req->cba);
690 else
691 kfree(req->rcall);
692
693 wake_up(&m->equeue);
694 }
695 } else {
696 if (err >= 0 && rcall->id != P9_RFLUSH)
697 P9_DPRINTK(P9_DEBUG_ERROR,
698 "unexpected response mux %p id %d tag %d\n",
699 m, rcall->id, rcall->tag);
700 kfree(rcall);
701 }
702 }
703
704 if (!list_empty(&m->req_list)) {
705 if (test_and_clear_bit(Rpending, &m->wsched))
706 n = POLLIN;
707 else
708 n = m->trans->poll(m->trans, NULL);
709
710 if (n & POLLIN) {
711 P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
712 queue_work(p9_mux_wq, &m->rq);
713 } else
714 clear_bit(Rworksched, &m->wsched);
715 } else
716 clear_bit(Rworksched, &m->wsched);
717
718 return;
719
720 error:
721 p9_conn_cancel(m, err);
722 clear_bit(Rworksched, &m->wsched);
723 }
724
725 /**
726 * p9_send_request - send 9P request
727 * The function can sleep until the request is scheduled for sending.
728 * The function can be interrupted. Return from the function is not
729 * a guarantee that the request is sent successfully. Can return errors
730 * that can be retrieved by PTR_ERR macros.
731 *
732 * @m: mux data
733 * @tc: request to be sent
734 * @cb: callback function to call when response is received
735 * @cba: parameter to pass to the callback function
736 */
737 static struct p9_req *p9_send_request(struct p9_conn *m,
738 struct p9_fcall *tc,
739 p9_conn_req_callback cb, void *cba)
740 {
741 int n;
742 struct p9_req *req;
743
744 P9_DPRINTK(P9_DEBUG_MUX, "mux %p task %p tcall %p id %d\n", m, current,
745 tc, tc->id);
746 if (m->err < 0)
747 return ERR_PTR(m->err);
748
749 req = kmalloc(sizeof(struct p9_req), GFP_KERNEL);
750 if (!req)
751 return ERR_PTR(-ENOMEM);
752
753 if (tc->id == P9_TVERSION)
754 n = P9_NOTAG;
755 else
756 n = p9_mux_get_tag(m);
757
758 if (n < 0)
759 return ERR_PTR(-ENOMEM);
760
761 p9_set_tag(tc, n);
762
763 #ifdef CONFIG_NET_9P_DEBUG
764 if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
765 char buf[150];
766
767 p9_printfcall(buf, sizeof(buf), tc, *m->extended);
768 printk(KERN_NOTICE "<<< %p %s\n", m, buf);
769 }
770 #endif
771
772 spin_lock_init(&req->lock);
773 req->tag = n;
774 req->tcall = tc;
775 req->rcall = NULL;
776 req->err = 0;
777 req->cb = cb;
778 req->cba = cba;
779 req->flush = None;
780
781 spin_lock(&m->lock);
782 list_add_tail(&req->req_list, &m->unsent_req_list);
783 spin_unlock(&m->lock);
784
785 if (test_and_clear_bit(Wpending, &m->wsched))
786 n = POLLOUT;
787 else
788 n = m->trans->poll(m->trans, NULL);
789
790 if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
791 queue_work(p9_mux_wq, &m->wq);
792
793 return req;
794 }
795
796 static void p9_mux_free_request(struct p9_conn *m, struct p9_req *req)
797 {
798 p9_mux_put_tag(m, req->tag);
799 kfree(req);
800 }
801
802 static void p9_mux_flush_cb(struct p9_req *freq, void *a)
803 {
804 p9_conn_req_callback cb;
805 int tag;
806 struct p9_conn *m;
807 struct p9_req *req, *rreq, *rptr;
808
809 m = a;
810 P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
811 freq->tcall, freq->rcall, freq->err,
812 freq->tcall->params.tflush.oldtag);
813
814 spin_lock(&m->lock);
815 cb = NULL;
816 tag = freq->tcall->params.tflush.oldtag;
817 req = NULL;
818 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
819 if (rreq->tag == tag) {
820 req = rreq;
821 list_del(&req->req_list);
822 break;
823 }
824 }
825 spin_unlock(&m->lock);
826
827 if (req) {
828 spin_lock(&req->lock);
829 req->flush = Flushed;
830 spin_unlock(&req->lock);
831
832 if (req->cb)
833 (*req->cb) (req, req->cba);
834 else
835 kfree(req->rcall);
836
837 wake_up(&m->equeue);
838 }
839
840 kfree(freq->tcall);
841 kfree(freq->rcall);
842 p9_mux_free_request(m, freq);
843 }
844
845 static int
846 p9_mux_flush_request(struct p9_conn *m, struct p9_req *req)
847 {
848 struct p9_fcall *fc;
849 struct p9_req *rreq, *rptr;
850
851 P9_DPRINTK(P9_DEBUG_MUX, "mux %p req %p tag %d\n", m, req, req->tag);
852
853 /* if a response was received for a request, do nothing */
854 spin_lock(&req->lock);
855 if (req->rcall || req->err) {
856 spin_unlock(&req->lock);
857 P9_DPRINTK(P9_DEBUG_MUX,
858 "mux %p req %p response already received\n", m, req);
859 return 0;
860 }
861
862 req->flush = Flushing;
863 spin_unlock(&req->lock);
864
865 spin_lock(&m->lock);
866 /* if the request is not sent yet, just remove it from the list */
867 list_for_each_entry_safe(rreq, rptr, &m->unsent_req_list, req_list) {
868 if (rreq->tag == req->tag) {
869 P9_DPRINTK(P9_DEBUG_MUX,
870 "mux %p req %p request is not sent yet\n", m, req);
871 list_del(&rreq->req_list);
872 req->flush = Flushed;
873 spin_unlock(&m->lock);
874 if (req->cb)
875 (*req->cb) (req, req->cba);
876 return 0;
877 }
878 }
879 spin_unlock(&m->lock);
880
881 clear_thread_flag(TIF_SIGPENDING);
882 fc = p9_create_tflush(req->tag);
883 p9_send_request(m, fc, p9_mux_flush_cb, m);
884 return 1;
885 }
886
887 static void
888 p9_conn_rpc_cb(struct p9_req *req, void *a)
889 {
890 struct p9_mux_rpc *r;
891
892 P9_DPRINTK(P9_DEBUG_MUX, "req %p r %p\n", req, a);
893 r = a;
894 r->rcall = req->rcall;
895 r->err = req->err;
896
897 if (req->flush != None && !req->err)
898 r->err = -ERESTARTSYS;
899
900 wake_up(&r->wqueue);
901 }
902
903 /**
904 * p9_mux_rpc - sends 9P request and waits until a response is available.
905 * The function can be interrupted.
906 * @m: mux data
907 * @tc: request to be sent
908 * @rc: pointer where a pointer to the response is stored
909 */
910 int
911 p9_conn_rpc(struct p9_conn *m, struct p9_fcall *tc,
912 struct p9_fcall **rc)
913 {
914 int err, sigpending;
915 unsigned long flags;
916 struct p9_req *req;
917 struct p9_mux_rpc r;
918
919 r.err = 0;
920 r.tcall = tc;
921 r.rcall = NULL;
922 r.m = m;
923 init_waitqueue_head(&r.wqueue);
924
925 if (rc)
926 *rc = NULL;
927
928 sigpending = 0;
929 if (signal_pending(current)) {
930 sigpending = 1;
931 clear_thread_flag(TIF_SIGPENDING);
932 }
933
934 req = p9_send_request(m, tc, p9_conn_rpc_cb, &r);
935 if (IS_ERR(req)) {
936 err = PTR_ERR(req);
937 P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
938 return err;
939 }
940
941 err = wait_event_interruptible(r.wqueue, r.rcall != NULL || r.err < 0);
942 if (r.err < 0)
943 err = r.err;
944
945 if (err == -ERESTARTSYS && m->trans->status == Connected
946 && m->err == 0) {
947 if (p9_mux_flush_request(m, req)) {
948 /* wait until we get response of the flush message */
949 do {
950 clear_thread_flag(TIF_SIGPENDING);
951 err = wait_event_interruptible(r.wqueue,
952 r.rcall || r.err);
953 } while (!r.rcall && !r.err && err == -ERESTARTSYS &&
954 m->trans->status == Connected && !m->err);
955
956 err = -ERESTARTSYS;
957 }
958 sigpending = 1;
959 }
960
961 if (sigpending) {
962 spin_lock_irqsave(&current->sighand->siglock, flags);
963 recalc_sigpending();
964 spin_unlock_irqrestore(&current->sighand->siglock, flags);
965 }
966
967 if (rc)
968 *rc = r.rcall;
969 else
970 kfree(r.rcall);
971
972 p9_mux_free_request(m, req);
973 if (err > 0)
974 err = -EIO;
975
976 return err;
977 }
978 EXPORT_SYMBOL(p9_conn_rpc);
979
980 #ifdef P9_NONBLOCK
981 /**
982 * p9_conn_rpcnb - sends 9P request without waiting for response.
983 * @m: mux data
984 * @tc: request to be sent
985 * @cb: callback function to be called when response arrives
986 * @cba: value to pass to the callback function
987 */
988 int p9_conn_rpcnb(struct p9_conn *m, struct p9_fcall *tc,
989 p9_conn_req_callback cb, void *a)
990 {
991 int err;
992 struct p9_req *req;
993
994 req = p9_send_request(m, tc, cb, a);
995 if (IS_ERR(req)) {
996 err = PTR_ERR(req);
997 P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
998 return PTR_ERR(req);
999 }
1000
1001 P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p tag %d\n", m, tc, req->tag);
1002 return 0;
1003 }
1004 EXPORT_SYMBOL(p9_conn_rpcnb);
1005 #endif /* P9_NONBLOCK */
1006
1007 /**
1008 * p9_conn_cancel - cancel all pending requests with error
1009 * @m: mux data
1010 * @err: error code
1011 */
1012 void p9_conn_cancel(struct p9_conn *m, int err)
1013 {
1014 struct p9_req *req, *rtmp;
1015 LIST_HEAD(cancel_list);
1016
1017 P9_DPRINTK(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
1018 m->err = err;
1019 spin_lock(&m->lock);
1020 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
1021 list_move(&req->req_list, &cancel_list);
1022 }
1023 list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
1024 list_move(&req->req_list, &cancel_list);
1025 }
1026 spin_unlock(&m->lock);
1027
1028 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
1029 list_del(&req->req_list);
1030 if (!req->err)
1031 req->err = err;
1032
1033 if (req->cb)
1034 (*req->cb) (req, req->cba);
1035 else
1036 kfree(req->rcall);
1037 }
1038
1039 wake_up(&m->equeue);
1040 }
1041 EXPORT_SYMBOL(p9_conn_cancel);
1042
1043 static u16 p9_mux_get_tag(struct p9_conn *m)
1044 {
1045 int tag;
1046
1047 tag = p9_idpool_get(m->tagpool);
1048 if (tag < 0)
1049 return P9_NOTAG;
1050 else
1051 return (u16) tag;
1052 }
1053
1054 static void p9_mux_put_tag(struct p9_conn *m, u16 tag)
1055 {
1056 if (tag != P9_NOTAG && p9_idpool_check(tag, m->tagpool))
1057 p9_idpool_put(tag, m->tagpool);
1058 }
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