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[SCSI] a4000t, zorro7xx, mvme16x, bvme6000,sim710: xxx_device_remove seems buggy
[linux-2.6/x86.git] / net / 9p / mux.c
blobacb038810f3995c2b5c4b7e742d91e34c33d83bc
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 <net/9p/transport.h>
35 #include <net/9p/conn.h>
36
37 #define ERREQFLUSH 1
38 #define SCHED_TIMEOUT 10
39 #define MAXPOLLWADDR 2
40
41 enum {
42 Rworksched = 1, /* read work scheduled or running */
43 Rpending = 2, /* can read */
44 Wworksched = 4, /* write work scheduled or running */
45 Wpending = 8, /* can write */
46 };
47
48 enum {
49 None,
50 Flushing,
51 Flushed,
52 };
53
54 struct p9_mux_poll_task;
55
56 struct p9_req {
57 spinlock_t lock; /* protect request structure */
58 int tag;
59 struct p9_fcall *tcall;
60 struct p9_fcall *rcall;
61 int err;
62 p9_conn_req_callback cb;
63 void *cba;
64 int flush;
65 struct list_head req_list;
66 };
67
68 struct p9_conn {
69 spinlock_t lock; /* protect lock structure */
70 struct list_head mux_list;
71 struct p9_mux_poll_task *poll_task;
72 int msize;
73 unsigned char *extended;
74 struct p9_transport *trans;
75 struct p9_idpool *tagpool;
76 int err;
77 wait_queue_head_t equeue;
78 struct list_head req_list;
79 struct list_head unsent_req_list;
80 struct p9_fcall *rcall;
81 int rpos;
82 char *rbuf;
83 int wpos;
84 int wsize;
85 char *wbuf;
86 wait_queue_t poll_wait[MAXPOLLWADDR];
87 wait_queue_head_t *poll_waddr[MAXPOLLWADDR];
88 poll_table pt;
89 struct work_struct rq;
90 struct work_struct wq;
91 unsigned long wsched;
92 };
93
94 struct p9_mux_poll_task {
95 struct task_struct *task;
96 struct list_head mux_list;
97 int muxnum;
98 };
99
100 struct p9_mux_rpc {
101 struct p9_conn *m;
102 int err;
103 struct p9_fcall *tcall;
104 struct p9_fcall *rcall;
105 wait_queue_head_t wqueue;
106 };
107
108 static int p9_poll_proc(void *);
109 static void p9_read_work(struct work_struct *work);
110 static void p9_write_work(struct work_struct *work);
111 static void p9_pollwait(struct file *filp, wait_queue_head_t *wait_address,
112 poll_table * p);
113 static u16 p9_mux_get_tag(struct p9_conn *);
114 static void p9_mux_put_tag(struct p9_conn *, u16);
115
116 static DEFINE_MUTEX(p9_mux_task_lock);
117 static struct workqueue_struct *p9_mux_wq;
118
119 static int p9_mux_num;
120 static int p9_mux_poll_task_num;
121 static struct p9_mux_poll_task p9_mux_poll_tasks[100];
122
123 int p9_mux_global_init(void)
124 {
125 int i;
126
127 for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++)
128 p9_mux_poll_tasks[i].task = NULL;
129
130 p9_mux_wq = create_workqueue("v9fs");
131 if (!p9_mux_wq) {
132 printk(KERN_WARNING "v9fs: mux: creating workqueue failed\n");
133 return -ENOMEM;
134 }
135
136 return 0;
137 }
138
139 void p9_mux_global_exit(void)
140 {
141 destroy_workqueue(p9_mux_wq);
142 }
143
144 /**
145 * p9_mux_calc_poll_procs - calculates the number of polling procs
146 * based on the number of mounted v9fs filesystems.
147 *
148 * The current implementation returns sqrt of the number of mounts.
149 */
150 static int p9_mux_calc_poll_procs(int muxnum)
151 {
152 int n;
153
154 if (p9_mux_poll_task_num)
155 n = muxnum / p9_mux_poll_task_num +
156 (muxnum % p9_mux_poll_task_num ? 1 : 0);
157 else
158 n = 1;
159
160 if (n > ARRAY_SIZE(p9_mux_poll_tasks))
161 n = ARRAY_SIZE(p9_mux_poll_tasks);
162
163 return n;
164 }
165
166 static int p9_mux_poll_start(struct p9_conn *m)
167 {
168 int i, n;
169 struct p9_mux_poll_task *vpt, *vptlast;
170 struct task_struct *pproc;
171
172 P9_DPRINTK(P9_DEBUG_MUX, "mux %p muxnum %d procnum %d\n", m, p9_mux_num,
173 p9_mux_poll_task_num);
174 mutex_lock(&p9_mux_task_lock);
175
176 n = p9_mux_calc_poll_procs(p9_mux_num + 1);
177 if (n > p9_mux_poll_task_num) {
178 for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++) {
179 if (p9_mux_poll_tasks[i].task == NULL) {
180 vpt = &p9_mux_poll_tasks[i];
181 P9_DPRINTK(P9_DEBUG_MUX, "create proc %p\n",
182 vpt);
183 pproc = kthread_create(p9_poll_proc, vpt,
184 "v9fs-poll");
185
186 if (!IS_ERR(pproc)) {
187 vpt->task = pproc;
188 INIT_LIST_HEAD(&vpt->mux_list);
189 vpt->muxnum = 0;
190 p9_mux_poll_task_num++;
191 wake_up_process(vpt->task);
192 }
193 break;
194 }
195 }
196
197 if (i >= ARRAY_SIZE(p9_mux_poll_tasks))
198 P9_DPRINTK(P9_DEBUG_ERROR,
199 "warning: no free poll slots\n");
200 }
201
202 n = (p9_mux_num + 1) / p9_mux_poll_task_num +
203 ((p9_mux_num + 1) % p9_mux_poll_task_num ? 1 : 0);
204
205 vptlast = NULL;
206 for (i = 0; i < ARRAY_SIZE(p9_mux_poll_tasks); i++) {
207 vpt = &p9_mux_poll_tasks[i];
208 if (vpt->task != NULL) {
209 vptlast = vpt;
210 if (vpt->muxnum < n) {
211 P9_DPRINTK(P9_DEBUG_MUX, "put in proc %d\n", i);
212 list_add(&m->mux_list, &vpt->mux_list);
213 vpt->muxnum++;
214 m->poll_task = vpt;
215 memset(&m->poll_waddr, 0,
216 sizeof(m->poll_waddr));
217 init_poll_funcptr(&m->pt, p9_pollwait);
218 break;
219 }
220 }
221 }
222
223 if (i >= ARRAY_SIZE(p9_mux_poll_tasks)) {
224 if (vptlast == NULL)
225 return -ENOMEM;
226
227 P9_DPRINTK(P9_DEBUG_MUX, "put in proc %d\n", i);
228 list_add(&m->mux_list, &vptlast->mux_list);
229 vptlast->muxnum++;
230 m->poll_task = vptlast;
231 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
232 init_poll_funcptr(&m->pt, p9_pollwait);
233 }
234
235 p9_mux_num++;
236 mutex_unlock(&p9_mux_task_lock);
237
238 return 0;
239 }
240
241 static void p9_mux_poll_stop(struct p9_conn *m)
242 {
243 int i;
244 struct p9_mux_poll_task *vpt;
245
246 mutex_lock(&p9_mux_task_lock);
247 vpt = m->poll_task;
248 list_del(&m->mux_list);
249 for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
250 if (m->poll_waddr[i] != NULL) {
251 remove_wait_queue(m->poll_waddr[i], &m->poll_wait[i]);
252 m->poll_waddr[i] = NULL;
253 }
254 }
255 vpt->muxnum--;
256 if (!vpt->muxnum) {
257 P9_DPRINTK(P9_DEBUG_MUX, "destroy proc %p\n", vpt);
258 kthread_stop(vpt->task);
259 vpt->task = NULL;
260 p9_mux_poll_task_num--;
261 }
262 p9_mux_num--;
263 mutex_unlock(&p9_mux_task_lock);
264 }
265
266 /**
267 * p9_conn_create - allocate and initialize the per-session mux data
268 * Creates the polling task if this is the first session.
269 *
270 * @trans - transport structure
271 * @msize - maximum message size
272 * @extended - pointer to the extended flag
273 */
274 struct p9_conn *p9_conn_create(struct p9_transport *trans, int msize,
275 unsigned char *extended)
276 {
277 int i, n;
278 struct p9_conn *m, *mtmp;
279
280 P9_DPRINTK(P9_DEBUG_MUX, "transport %p msize %d\n", trans, msize);
281 m = kmalloc(sizeof(struct p9_conn), GFP_KERNEL);
282 if (!m)
283 return ERR_PTR(-ENOMEM);
284
285 spin_lock_init(&m->lock);
286 INIT_LIST_HEAD(&m->mux_list);
287 m->msize = msize;
288 m->extended = extended;
289 m->trans = trans;
290 m->tagpool = p9_idpool_create();
291 if (!m->tagpool) {
292 kfree(m);
293 return ERR_PTR(PTR_ERR(m->tagpool));
294 }
295
296 m->err = 0;
297 init_waitqueue_head(&m->equeue);
298 INIT_LIST_HEAD(&m->req_list);
299 INIT_LIST_HEAD(&m->unsent_req_list);
300 m->rcall = NULL;
301 m->rpos = 0;
302 m->rbuf = NULL;
303 m->wpos = m->wsize = 0;
304 m->wbuf = NULL;
305 INIT_WORK(&m->rq, p9_read_work);
306 INIT_WORK(&m->wq, p9_write_work);
307 m->wsched = 0;
308 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
309 m->poll_task = NULL;
310 n = p9_mux_poll_start(m);
311 if (n)
312 return ERR_PTR(n);
313
314 n = trans->poll(trans, &m->pt);
315 if (n & POLLIN) {
316 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
317 set_bit(Rpending, &m->wsched);
318 }
319
320 if (n & POLLOUT) {
321 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
322 set_bit(Wpending, &m->wsched);
323 }
324
325 for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
326 if (IS_ERR(m->poll_waddr[i])) {
327 p9_mux_poll_stop(m);
328 mtmp = (void *)m->poll_waddr; /* the error code */
329 kfree(m);
330 m = mtmp;
331 break;
332 }
333 }
334
335 return m;
336 }
337 EXPORT_SYMBOL(p9_conn_create);
338
339 /**
340 * p9_mux_destroy - cancels all pending requests and frees mux resources
341 */
342 void p9_conn_destroy(struct p9_conn *m)
343 {
344 P9_DPRINTK(P9_DEBUG_MUX, "mux %p prev %p next %p\n", m,
345 m->mux_list.prev, m->mux_list.next);
346 p9_conn_cancel(m, -ECONNRESET);
347
348 if (!list_empty(&m->req_list)) {
349 /* wait until all processes waiting on this session exit */
350 P9_DPRINTK(P9_DEBUG_MUX,
351 "mux %p waiting for empty request queue\n", m);
352 wait_event_timeout(m->equeue, (list_empty(&m->req_list)), 5000);
353 P9_DPRINTK(P9_DEBUG_MUX, "mux %p request queue empty: %d\n", m,
354 list_empty(&m->req_list));
355 }
356
357 p9_mux_poll_stop(m);
358 m->trans = NULL;
359 p9_idpool_destroy(m->tagpool);
360 kfree(m);
361 }
362 EXPORT_SYMBOL(p9_conn_destroy);
363
364 /**
365 * p9_pollwait - called by files poll operation to add v9fs-poll task
366 * to files wait queue
367 */
368 static void
369 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address,
370 poll_table * p)
371 {
372 int i;
373 struct p9_conn *m;
374
375 m = container_of(p, struct p9_conn, pt);
376 for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++)
377 if (m->poll_waddr[i] == NULL)
378 break;
379
380 if (i >= ARRAY_SIZE(m->poll_waddr)) {
381 P9_DPRINTK(P9_DEBUG_ERROR, "not enough wait_address slots\n");
382 return;
383 }
384
385 m->poll_waddr[i] = wait_address;
386
387 if (!wait_address) {
388 P9_DPRINTK(P9_DEBUG_ERROR, "no wait_address\n");
389 m->poll_waddr[i] = ERR_PTR(-EIO);
390 return;
391 }
392
393 init_waitqueue_entry(&m->poll_wait[i], m->poll_task->task);
394 add_wait_queue(wait_address, &m->poll_wait[i]);
395 }
396
397 /**
398 * p9_poll_mux - polls a mux and schedules read or write works if necessary
399 */
400 static void p9_poll_mux(struct p9_conn *m)
401 {
402 int n;
403
404 if (m->err < 0)
405 return;
406
407 n = m->trans->poll(m->trans, NULL);
408 if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) {
409 P9_DPRINTK(P9_DEBUG_MUX, "error mux %p err %d\n", m, n);
410 if (n >= 0)
411 n = -ECONNRESET;
412 p9_conn_cancel(m, n);
413 }
414
415 if (n & POLLIN) {
416 set_bit(Rpending, &m->wsched);
417 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
418 if (!test_and_set_bit(Rworksched, &m->wsched)) {
419 P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
420 queue_work(p9_mux_wq, &m->rq);
421 }
422 }
423
424 if (n & POLLOUT) {
425 set_bit(Wpending, &m->wsched);
426 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
427 if ((m->wsize || !list_empty(&m->unsent_req_list))
428 && !test_and_set_bit(Wworksched, &m->wsched)) {
429 P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
430 queue_work(p9_mux_wq, &m->wq);
431 }
432 }
433 }
434
435 /**
436 * p9_poll_proc - polls all v9fs transports for new events and queues
437 * the appropriate work to the work queue
438 */
439 static int p9_poll_proc(void *a)
440 {
441 struct p9_conn *m, *mtmp;
442 struct p9_mux_poll_task *vpt;
443
444 vpt = a;
445 P9_DPRINTK(P9_DEBUG_MUX, "start %p %p\n", current, vpt);
446 while (!kthread_should_stop()) {
447 set_current_state(TASK_INTERRUPTIBLE);
448
449 list_for_each_entry_safe(m, mtmp, &vpt->mux_list, mux_list) {
450 p9_poll_mux(m);
451 }
452
453 P9_DPRINTK(P9_DEBUG_MUX, "sleeping...\n");
454 schedule_timeout(SCHED_TIMEOUT * HZ);
455 }
456
457 __set_current_state(TASK_RUNNING);
458 P9_DPRINTK(P9_DEBUG_MUX, "finish\n");
459 return 0;
460 }
461
462 /**
463 * p9_write_work - called when a transport can send some data
464 */
465 static void p9_write_work(struct work_struct *work)
466 {
467 int n, err;
468 struct p9_conn *m;
469 struct p9_req *req;
470
471 m = container_of(work, struct p9_conn, wq);
472
473 if (m->err < 0) {
474 clear_bit(Wworksched, &m->wsched);
475 return;
476 }
477
478 if (!m->wsize) {
479 if (list_empty(&m->unsent_req_list)) {
480 clear_bit(Wworksched, &m->wsched);
481 return;
482 }
483
484 spin_lock(&m->lock);
485 again:
486 req = list_entry(m->unsent_req_list.next, struct p9_req,
487 req_list);
488 list_move_tail(&req->req_list, &m->req_list);
489 if (req->err == ERREQFLUSH)
490 goto again;
491
492 m->wbuf = req->tcall->sdata;
493 m->wsize = req->tcall->size;
494 m->wpos = 0;
495 spin_unlock(&m->lock);
496 }
497
498 P9_DPRINTK(P9_DEBUG_MUX, "mux %p pos %d size %d\n", m, m->wpos,
499 m->wsize);
500 clear_bit(Wpending, &m->wsched);
501 err = m->trans->write(m->trans, m->wbuf + m->wpos, m->wsize - m->wpos);
502 P9_DPRINTK(P9_DEBUG_MUX, "mux %p sent %d bytes\n", m, err);
503 if (err == -EAGAIN) {
504 clear_bit(Wworksched, &m->wsched);
505 return;
506 }
507
508 if (err < 0)
509 goto error;
510 else if (err == 0) {
511 err = -EREMOTEIO;
512 goto error;
513 }
514
515 m->wpos += err;
516 if (m->wpos == m->wsize)
517 m->wpos = m->wsize = 0;
518
519 if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
520 if (test_and_clear_bit(Wpending, &m->wsched))
521 n = POLLOUT;
522 else
523 n = m->trans->poll(m->trans, NULL);
524
525 if (n & POLLOUT) {
526 P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
527 queue_work(p9_mux_wq, &m->wq);
528 } else
529 clear_bit(Wworksched, &m->wsched);
530 } else
531 clear_bit(Wworksched, &m->wsched);
532
533 return;
534
535 error:
536 p9_conn_cancel(m, err);
537 clear_bit(Wworksched, &m->wsched);
538 }
539
540 static void process_request(struct p9_conn *m, struct p9_req *req)
541 {
542 int ecode;
543 struct p9_str *ename;
544
545 if (!req->err && req->rcall->id == P9_RERROR) {
546 ecode = req->rcall->params.rerror.errno;
547 ename = &req->rcall->params.rerror.error;
548
549 P9_DPRINTK(P9_DEBUG_MUX, "Rerror %.*s\n", ename->len,
550 ename->str);
551
552 if (*m->extended)
553 req->err = -ecode;
554
555 if (!req->err) {
556 req->err = p9_errstr2errno(ename->str, ename->len);
557
558 if (!req->err) { /* string match failed */
559 PRINT_FCALL_ERROR("unknown error", req->rcall);
560 }
561
562 if (!req->err)
563 req->err = -ESERVERFAULT;
564 }
565 } else if (req->tcall && req->rcall->id != req->tcall->id + 1) {
566 P9_DPRINTK(P9_DEBUG_ERROR,
567 "fcall mismatch: expected %d, got %d\n",
568 req->tcall->id + 1, req->rcall->id);
569 if (!req->err)
570 req->err = -EIO;
571 }
572 }
573
574 /**
575 * p9_read_work - called when there is some data to be read from a transport
576 */
577 static void p9_read_work(struct work_struct *work)
578 {
579 int n, err;
580 struct p9_conn *m;
581 struct p9_req *req, *rptr, *rreq;
582 struct p9_fcall *rcall;
583 char *rbuf;
584
585 m = container_of(work, struct p9_conn, rq);
586
587 if (m->err < 0)
588 return;
589
590 rcall = NULL;
591 P9_DPRINTK(P9_DEBUG_MUX, "start mux %p pos %d\n", m, m->rpos);
592
593 if (!m->rcall) {
594 m->rcall =
595 kmalloc(sizeof(struct p9_fcall) + m->msize, GFP_KERNEL);
596 if (!m->rcall) {
597 err = -ENOMEM;
598 goto error;
599 }
600
601 m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
602 m->rpos = 0;
603 }
604
605 clear_bit(Rpending, &m->wsched);
606 err = m->trans->read(m->trans, m->rbuf + m->rpos, m->msize - m->rpos);
607 P9_DPRINTK(P9_DEBUG_MUX, "mux %p got %d bytes\n", m, err);
608 if (err == -EAGAIN) {
609 clear_bit(Rworksched, &m->wsched);
610 return;
611 }
612
613 if (err <= 0)
614 goto error;
615
616 m->rpos += err;
617 while (m->rpos > 4) {
618 n = le32_to_cpu(*(__le32 *) m->rbuf);
619 if (n >= m->msize) {
620 P9_DPRINTK(P9_DEBUG_ERROR,
621 "requested packet size too big: %d\n", n);
622 err = -EIO;
623 goto error;
624 }
625
626 if (m->rpos < n)
627 break;
628
629 err =
630 p9_deserialize_fcall(m->rbuf, n, m->rcall, *m->extended);
631 if (err < 0) {
632 goto error;
633 }
634
635 #ifdef CONFIG_NET_9P_DEBUG
636 if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
637 char buf[150];
638
639 p9_printfcall(buf, sizeof(buf), m->rcall,
640 *m->extended);
641 printk(KERN_NOTICE ">>> %p %s\n", m, buf);
642 }
643 #endif
644
645 rcall = m->rcall;
646 rbuf = m->rbuf;
647 if (m->rpos > n) {
648 m->rcall = kmalloc(sizeof(struct p9_fcall) + m->msize,
649 GFP_KERNEL);
650 if (!m->rcall) {
651 err = -ENOMEM;
652 goto error;
653 }
654
655 m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
656 memmove(m->rbuf, rbuf + n, m->rpos - n);
657 m->rpos -= n;
658 } else {
659 m->rcall = NULL;
660 m->rbuf = NULL;
661 m->rpos = 0;
662 }
663
664 P9_DPRINTK(P9_DEBUG_MUX, "mux %p fcall id %d tag %d\n", m,
665 rcall->id, rcall->tag);
666
667 req = NULL;
668 spin_lock(&m->lock);
669 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
670 if (rreq->tag == rcall->tag) {
671 req = rreq;
672 if (req->flush != Flushing)
673 list_del(&req->req_list);
674 break;
675 }
676 }
677 spin_unlock(&m->lock);
678
679 if (req) {
680 req->rcall = rcall;
681 process_request(m, req);
682
683 if (req->flush != Flushing) {
684 if (req->cb)
685 (*req->cb) (req, req->cba);
686 else
687 kfree(req->rcall);
688
689 wake_up(&m->equeue);
690 }
691 } else {
692 if (err >= 0 && rcall->id != P9_RFLUSH)
693 P9_DPRINTK(P9_DEBUG_ERROR,
694 "unexpected response mux %p id %d tag %d\n",
695 m, rcall->id, rcall->tag);
696 kfree(rcall);
697 }
698 }
699
700 if (!list_empty(&m->req_list)) {
701 if (test_and_clear_bit(Rpending, &m->wsched))
702 n = POLLIN;
703 else
704 n = m->trans->poll(m->trans, NULL);
705
706 if (n & POLLIN) {
707 P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
708 queue_work(p9_mux_wq, &m->rq);
709 } else
710 clear_bit(Rworksched, &m->wsched);
711 } else
712 clear_bit(Rworksched, &m->wsched);
713
714 return;
715
716 error:
717 p9_conn_cancel(m, err);
718 clear_bit(Rworksched, &m->wsched);
719 }
720
721 /**
722 * p9_send_request - send 9P request
723 * The function can sleep until the request is scheduled for sending.
724 * The function can be interrupted. Return from the function is not
725 * a guarantee that the request is sent successfully. Can return errors
726 * that can be retrieved by PTR_ERR macros.
727 *
728 * @m: mux data
729 * @tc: request to be sent
730 * @cb: callback function to call when response is received
731 * @cba: parameter to pass to the callback function
732 */
733 static struct p9_req *p9_send_request(struct p9_conn *m,
734 struct p9_fcall *tc,
735 p9_conn_req_callback cb, void *cba)
736 {
737 int n;
738 struct p9_req *req;
739
740 P9_DPRINTK(P9_DEBUG_MUX, "mux %p task %p tcall %p id %d\n", m, current,
741 tc, tc->id);
742 if (m->err < 0)
743 return ERR_PTR(m->err);
744
745 req = kmalloc(sizeof(struct p9_req), GFP_KERNEL);
746 if (!req)
747 return ERR_PTR(-ENOMEM);
748
749 if (tc->id == P9_TVERSION)
750 n = P9_NOTAG;
751 else
752 n = p9_mux_get_tag(m);
753
754 if (n < 0)
755 return ERR_PTR(-ENOMEM);
756
757 p9_set_tag(tc, n);
758
759 #ifdef CONFIG_NET_9P_DEBUG
760 if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
761 char buf[150];
762
763 p9_printfcall(buf, sizeof(buf), tc, *m->extended);
764 printk(KERN_NOTICE "<<< %p %s\n", m, buf);
765 }
766 #endif
767
768 spin_lock_init(&req->lock);
769 req->tag = n;
770 req->tcall = tc;
771 req->rcall = NULL;
772 req->err = 0;
773 req->cb = cb;
774 req->cba = cba;
775 req->flush = None;
776
777 spin_lock(&m->lock);
778 list_add_tail(&req->req_list, &m->unsent_req_list);
779 spin_unlock(&m->lock);
780
781 if (test_and_clear_bit(Wpending, &m->wsched))
782 n = POLLOUT;
783 else
784 n = m->trans->poll(m->trans, NULL);
785
786 if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
787 queue_work(p9_mux_wq, &m->wq);
788
789 return req;
790 }
791
792 static void p9_mux_free_request(struct p9_conn *m, struct p9_req *req)
793 {
794 p9_mux_put_tag(m, req->tag);
795 kfree(req);
796 }
797
798 static void p9_mux_flush_cb(struct p9_req *freq, void *a)
799 {
800 p9_conn_req_callback cb;
801 int tag;
802 struct p9_conn *m;
803 struct p9_req *req, *rreq, *rptr;
804
805 m = a;
806 P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
807 freq->tcall, freq->rcall, freq->err,
808 freq->tcall->params.tflush.oldtag);
809
810 spin_lock(&m->lock);
811 cb = NULL;
812 tag = freq->tcall->params.tflush.oldtag;
813 req = NULL;
814 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
815 if (rreq->tag == tag) {
816 req = rreq;
817 list_del(&req->req_list);
818 break;
819 }
820 }
821 spin_unlock(&m->lock);
822
823 if (req) {
824 spin_lock(&req->lock);
825 req->flush = Flushed;
826 spin_unlock(&req->lock);
827
828 if (req->cb)
829 (*req->cb) (req, req->cba);
830 else
831 kfree(req->rcall);
832
833 wake_up(&m->equeue);
834 }
835
836 kfree(freq->tcall);
837 kfree(freq->rcall);
838 p9_mux_free_request(m, freq);
839 }
840
841 static int
842 p9_mux_flush_request(struct p9_conn *m, struct p9_req *req)
843 {
844 struct p9_fcall *fc;
845 struct p9_req *rreq, *rptr;
846
847 P9_DPRINTK(P9_DEBUG_MUX, "mux %p req %p tag %d\n", m, req, req->tag);
848
849 /* if a response was received for a request, do nothing */
850 spin_lock(&req->lock);
851 if (req->rcall || req->err) {
852 spin_unlock(&req->lock);
853 P9_DPRINTK(P9_DEBUG_MUX,
854 "mux %p req %p response already received\n", m, req);
855 return 0;
856 }
857
858 req->flush = Flushing;
859 spin_unlock(&req->lock);
860
861 spin_lock(&m->lock);
862 /* if the request is not sent yet, just remove it from the list */
863 list_for_each_entry_safe(rreq, rptr, &m->unsent_req_list, req_list) {
864 if (rreq->tag == req->tag) {
865 P9_DPRINTK(P9_DEBUG_MUX,
866 "mux %p req %p request is not sent yet\n", m, req);
867 list_del(&rreq->req_list);
868 req->flush = Flushed;
869 spin_unlock(&m->lock);
870 if (req->cb)
871 (*req->cb) (req, req->cba);
872 return 0;
873 }
874 }
875 spin_unlock(&m->lock);
876
877 clear_thread_flag(TIF_SIGPENDING);
878 fc = p9_create_tflush(req->tag);
879 p9_send_request(m, fc, p9_mux_flush_cb, m);
880 return 1;
881 }
882
883 static void
884 p9_conn_rpc_cb(struct p9_req *req, void *a)
885 {
886 struct p9_mux_rpc *r;
887
888 P9_DPRINTK(P9_DEBUG_MUX, "req %p r %p\n", req, a);
889 r = a;
890 r->rcall = req->rcall;
891 r->err = req->err;
892
893 if (req->flush != None && !req->err)
894 r->err = -ERESTARTSYS;
895
896 wake_up(&r->wqueue);
897 }
898
899 /**
900 * p9_mux_rpc - sends 9P request and waits until a response is available.
901 * The function can be interrupted.
902 * @m: mux data
903 * @tc: request to be sent
904 * @rc: pointer where a pointer to the response is stored
905 */
906 int
907 p9_conn_rpc(struct p9_conn *m, struct p9_fcall *tc,
908 struct p9_fcall **rc)
909 {
910 int err, sigpending;
911 unsigned long flags;
912 struct p9_req *req;
913 struct p9_mux_rpc r;
914
915 r.err = 0;
916 r.tcall = tc;
917 r.rcall = NULL;
918 r.m = m;
919 init_waitqueue_head(&r.wqueue);
920
921 if (rc)
922 *rc = NULL;
923
924 sigpending = 0;
925 if (signal_pending(current)) {
926 sigpending = 1;
927 clear_thread_flag(TIF_SIGPENDING);
928 }
929
930 req = p9_send_request(m, tc, p9_conn_rpc_cb, &r);
931 if (IS_ERR(req)) {
932 err = PTR_ERR(req);
933 P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
934 return err;
935 }
936
937 err = wait_event_interruptible(r.wqueue, r.rcall != NULL || r.err < 0);
938 if (r.err < 0)
939 err = r.err;
940
941 if (err == -ERESTARTSYS && m->trans->status == Connected
942 && m->err == 0) {
943 if (p9_mux_flush_request(m, req)) {
944 /* wait until we get response of the flush message */
945 do {
946 clear_thread_flag(TIF_SIGPENDING);
947 err = wait_event_interruptible(r.wqueue,
948 r.rcall || r.err);
949 } while (!r.rcall && !r.err && err == -ERESTARTSYS &&
950 m->trans->status == Connected && !m->err);
951
952 err = -ERESTARTSYS;
953 }
954 sigpending = 1;
955 }
956
957 if (sigpending) {
958 spin_lock_irqsave(&current->sighand->siglock, flags);
959 recalc_sigpending();
960 spin_unlock_irqrestore(&current->sighand->siglock, flags);
961 }
962
963 if (rc)
964 *rc = r.rcall;
965 else
966 kfree(r.rcall);
967
968 p9_mux_free_request(m, req);
969 if (err > 0)
970 err = -EIO;
971
972 return err;
973 }
974 EXPORT_SYMBOL(p9_conn_rpc);
975
976 #ifdef P9_NONBLOCK
977 /**
978 * p9_conn_rpcnb - sends 9P request without waiting for response.
979 * @m: mux data
980 * @tc: request to be sent
981 * @cb: callback function to be called when response arrives
982 * @cba: value to pass to the callback function
983 */
984 int p9_conn_rpcnb(struct p9_conn *m, struct p9_fcall *tc,
985 p9_conn_req_callback cb, void *a)
986 {
987 int err;
988 struct p9_req *req;
989
990 req = p9_send_request(m, tc, cb, a);
991 if (IS_ERR(req)) {
992 err = PTR_ERR(req);
993 P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
994 return PTR_ERR(req);
995 }
996
997 P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p tag %d\n", m, tc, req->tag);
998 return 0;
999 }
1000 EXPORT_SYMBOL(p9_conn_rpcnb);
1001 #endif /* P9_NONBLOCK */
1002
1003 /**
1004 * p9_conn_cancel - cancel all pending requests with error
1005 * @m: mux data
1006 * @err: error code
1007 */
1008 void p9_conn_cancel(struct p9_conn *m, int err)
1009 {
1010 struct p9_req *req, *rtmp;
1011 LIST_HEAD(cancel_list);
1012
1013 P9_DPRINTK(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
1014 m->err = err;
1015 spin_lock(&m->lock);
1016 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
1017 list_move(&req->req_list, &cancel_list);
1018 }
1019 list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
1020 list_move(&req->req_list, &cancel_list);
1021 }
1022 spin_unlock(&m->lock);
1023
1024 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
1025 list_del(&req->req_list);
1026 if (!req->err)
1027 req->err = err;
1028
1029 if (req->cb)
1030 (*req->cb) (req, req->cba);
1031 else
1032 kfree(req->rcall);
1033 }
1034
1035 wake_up(&m->equeue);
1036 }
1037 EXPORT_SYMBOL(p9_conn_cancel);
1038
1039 static u16 p9_mux_get_tag(struct p9_conn *m)
1040 {
1041 int tag;
1042
1043 tag = p9_idpool_get(m->tagpool);
1044 if (tag < 0)
1045 return P9_NOTAG;
1046 else
1047 return (u16) tag;
1048 }
1049
1050 static void p9_mux_put_tag(struct p9_conn *m, u16 tag)
1051 {
1052 if (tag != P9_NOTAG && p9_idpool_check(tag, m->tagpool))
1053 p9_idpool_put(tag, m->tagpool);
1054 }
x86 "subsystem" repository