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ext3: copy i_flags to inode flags on write
[deliverable/linux.git] / fs / 9p / mux.c
1 /*
2 * linux/fs/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
34 #include "debug.h"
35 #include "v9fs.h"
36 #include "9p.h"
37 #include "conv.h"
38 #include "transport.h"
39 #include "mux.h"
40
41 #define ERREQFLUSH 1
42 #define SCHED_TIMEOUT 10
43 #define MAXPOLLWADDR 2
44
45 enum {
46 Rworksched = 1, /* read work scheduled or running */
47 Rpending = 2, /* can read */
48 Wworksched = 4, /* write work scheduled or running */
49 Wpending = 8, /* can write */
50 };
51
52 enum {
53 None,
54 Flushing,
55 Flushed,
56 };
57
58 struct v9fs_mux_poll_task;
59
60 struct v9fs_req {
61 spinlock_t lock;
62 int tag;
63 struct v9fs_fcall *tcall;
64 struct v9fs_fcall *rcall;
65 int err;
66 v9fs_mux_req_callback cb;
67 void *cba;
68 int flush;
69 struct list_head req_list;
70 };
71
72 struct v9fs_mux_data {
73 spinlock_t lock;
74 struct list_head mux_list;
75 struct v9fs_mux_poll_task *poll_task;
76 int msize;
77 unsigned char *extended;
78 struct v9fs_transport *trans;
79 struct v9fs_idpool tagpool;
80 int err;
81 wait_queue_head_t equeue;
82 struct list_head req_list;
83 struct list_head unsent_req_list;
84 struct v9fs_fcall *rcall;
85 int rpos;
86 char *rbuf;
87 int wpos;
88 int wsize;
89 char *wbuf;
90 wait_queue_t poll_wait[MAXPOLLWADDR];
91 wait_queue_head_t *poll_waddr[MAXPOLLWADDR];
92 poll_table pt;
93 struct work_struct rq;
94 struct work_struct wq;
95 unsigned long wsched;
96 };
97
98 struct v9fs_mux_poll_task {
99 struct task_struct *task;
100 struct list_head mux_list;
101 int muxnum;
102 };
103
104 struct v9fs_mux_rpc {
105 struct v9fs_mux_data *m;
106 int err;
107 struct v9fs_fcall *tcall;
108 struct v9fs_fcall *rcall;
109 wait_queue_head_t wqueue;
110 };
111
112 static int v9fs_poll_proc(void *);
113 static void v9fs_read_work(struct work_struct *work);
114 static void v9fs_write_work(struct work_struct *work);
115 static void v9fs_pollwait(struct file *filp, wait_queue_head_t * wait_address,
116 poll_table * p);
117 static u16 v9fs_mux_get_tag(struct v9fs_mux_data *);
118 static void v9fs_mux_put_tag(struct v9fs_mux_data *, u16);
119
120 static DEFINE_MUTEX(v9fs_mux_task_lock);
121 static struct workqueue_struct *v9fs_mux_wq;
122
123 static int v9fs_mux_num;
124 static int v9fs_mux_poll_task_num;
125 static struct v9fs_mux_poll_task v9fs_mux_poll_tasks[100];
126
127 int v9fs_mux_global_init(void)
128 {
129 int i;
130
131 for (i = 0; i < ARRAY_SIZE(v9fs_mux_poll_tasks); i++)
132 v9fs_mux_poll_tasks[i].task = NULL;
133
134 v9fs_mux_wq = create_workqueue("v9fs");
135 if (!v9fs_mux_wq) {
136 printk(KERN_WARNING "v9fs: mux: creating workqueue failed\n");
137 return -ENOMEM;
138 }
139
140 return 0;
141 }
142
143 void v9fs_mux_global_exit(void)
144 {
145 destroy_workqueue(v9fs_mux_wq);
146 }
147
148 /**
149 * v9fs_mux_calc_poll_procs - calculates the number of polling procs
150 * based on the number of mounted v9fs filesystems.
151 *
152 * The current implementation returns sqrt of the number of mounts.
153 */
154 static int v9fs_mux_calc_poll_procs(int muxnum)
155 {
156 int n;
157
158 if (v9fs_mux_poll_task_num)
159 n = muxnum / v9fs_mux_poll_task_num +
160 (muxnum % v9fs_mux_poll_task_num ? 1 : 0);
161 else
162 n = 1;
163
164 if (n > ARRAY_SIZE(v9fs_mux_poll_tasks))
165 n = ARRAY_SIZE(v9fs_mux_poll_tasks);
166
167 return n;
168 }
169
170 static int v9fs_mux_poll_start(struct v9fs_mux_data *m)
171 {
172 int i, n;
173 struct v9fs_mux_poll_task *vpt, *vptlast;
174 struct task_struct *pproc;
175
176 dprintk(DEBUG_MUX, "mux %p muxnum %d procnum %d\n", m, v9fs_mux_num,
177 v9fs_mux_poll_task_num);
178 mutex_lock(&v9fs_mux_task_lock);
179
180 n = v9fs_mux_calc_poll_procs(v9fs_mux_num + 1);
181 if (n > v9fs_mux_poll_task_num) {
182 for (i = 0; i < ARRAY_SIZE(v9fs_mux_poll_tasks); i++) {
183 if (v9fs_mux_poll_tasks[i].task == NULL) {
184 vpt = &v9fs_mux_poll_tasks[i];
185 dprintk(DEBUG_MUX, "create proc %p\n", vpt);
186 pproc = kthread_create(v9fs_poll_proc, vpt,
187 "v9fs-poll");
188
189 if (!IS_ERR(pproc)) {
190 vpt->task = pproc;
191 INIT_LIST_HEAD(&vpt->mux_list);
192 vpt->muxnum = 0;
193 v9fs_mux_poll_task_num++;
194 wake_up_process(vpt->task);
195 }
196 break;
197 }
198 }
199
200 if (i >= ARRAY_SIZE(v9fs_mux_poll_tasks))
201 dprintk(DEBUG_ERROR, "warning: no free poll slots\n");
202 }
203
204 n = (v9fs_mux_num + 1) / v9fs_mux_poll_task_num +
205 ((v9fs_mux_num + 1) % v9fs_mux_poll_task_num ? 1 : 0);
206
207 vptlast = NULL;
208 for (i = 0; i < ARRAY_SIZE(v9fs_mux_poll_tasks); i++) {
209 vpt = &v9fs_mux_poll_tasks[i];
210 if (vpt->task != NULL) {
211 vptlast = vpt;
212 if (vpt->muxnum < n) {
213 dprintk(DEBUG_MUX, "put in proc %d\n", i);
214 list_add(&m->mux_list, &vpt->mux_list);
215 vpt->muxnum++;
216 m->poll_task = vpt;
217 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
218 init_poll_funcptr(&m->pt, v9fs_pollwait);
219 break;
220 }
221 }
222 }
223
224 if (i >= ARRAY_SIZE(v9fs_mux_poll_tasks)) {
225 if (vptlast == NULL)
226 return -ENOMEM;
227
228 dprintk(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, v9fs_pollwait);
234 }
235
236 v9fs_mux_num++;
237 mutex_unlock(&v9fs_mux_task_lock);
238
239 return 0;
240 }
241
242 static void v9fs_mux_poll_stop(struct v9fs_mux_data *m)
243 {
244 int i;
245 struct v9fs_mux_poll_task *vpt;
246
247 mutex_lock(&v9fs_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 dprintk(DEBUG_MUX, "destroy proc %p\n", vpt);
259 kthread_stop(vpt->task);
260 vpt->task = NULL;
261 v9fs_mux_poll_task_num--;
262 }
263 v9fs_mux_num--;
264 mutex_unlock(&v9fs_mux_task_lock);
265 }
266
267 /**
268 * v9fs_mux_init - 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 v9fs_mux_data *v9fs_mux_init(struct v9fs_transport *trans, int msize,
276 unsigned char *extended)
277 {
278 int i, n;
279 struct v9fs_mux_data *m, *mtmp;
280
281 dprintk(DEBUG_MUX, "transport %p msize %d\n", trans, msize);
282 m = kmalloc(sizeof(struct v9fs_mux_data), 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 idr_init(&m->tagpool.pool);
292 init_MUTEX(&m->tagpool.lock);
293 m->err = 0;
294 init_waitqueue_head(&m->equeue);
295 INIT_LIST_HEAD(&m->req_list);
296 INIT_LIST_HEAD(&m->unsent_req_list);
297 m->rcall = NULL;
298 m->rpos = 0;
299 m->rbuf = NULL;
300 m->wpos = m->wsize = 0;
301 m->wbuf = NULL;
302 INIT_WORK(&m->rq, v9fs_read_work);
303 INIT_WORK(&m->wq, v9fs_write_work);
304 m->wsched = 0;
305 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
306 m->poll_task = NULL;
307 n = v9fs_mux_poll_start(m);
308 if (n)
309 return ERR_PTR(n);
310
311 n = trans->poll(trans, &m->pt);
312 if (n & POLLIN) {
313 dprintk(DEBUG_MUX, "mux %p can read\n", m);
314 set_bit(Rpending, &m->wsched);
315 }
316
317 if (n & POLLOUT) {
318 dprintk(DEBUG_MUX, "mux %p can write\n", m);
319 set_bit(Wpending, &m->wsched);
320 }
321
322 for(i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
323 if (IS_ERR(m->poll_waddr[i])) {
324 v9fs_mux_poll_stop(m);
325 mtmp = (void *)m->poll_waddr; /* the error code */
326 kfree(m);
327 m = mtmp;
328 break;
329 }
330 }
331
332 return m;
333 }
334
335 /**
336 * v9fs_mux_destroy - cancels all pending requests and frees mux resources
337 */
338 void v9fs_mux_destroy(struct v9fs_mux_data *m)
339 {
340 dprintk(DEBUG_MUX, "mux %p prev %p next %p\n", m,
341 m->mux_list.prev, m->mux_list.next);
342 v9fs_mux_cancel(m, -ECONNRESET);
343
344 if (!list_empty(&m->req_list)) {
345 /* wait until all processes waiting on this session exit */
346 dprintk(DEBUG_MUX, "mux %p waiting for empty request queue\n",
347 m);
348 wait_event_timeout(m->equeue, (list_empty(&m->req_list)), 5000);
349 dprintk(DEBUG_MUX, "mux %p request queue empty: %d\n", m,
350 list_empty(&m->req_list));
351 }
352
353 v9fs_mux_poll_stop(m);
354 m->trans = NULL;
355
356 kfree(m);
357 }
358
359 /**
360 * v9fs_pollwait - called by files poll operation to add v9fs-poll task
361 * to files wait queue
362 */
363 static void
364 v9fs_pollwait(struct file *filp, wait_queue_head_t * wait_address,
365 poll_table * p)
366 {
367 int i;
368 struct v9fs_mux_data *m;
369
370 m = container_of(p, struct v9fs_mux_data, pt);
371 for(i = 0; i < ARRAY_SIZE(m->poll_waddr); i++)
372 if (m->poll_waddr[i] == NULL)
373 break;
374
375 if (i >= ARRAY_SIZE(m->poll_waddr)) {
376 dprintk(DEBUG_ERROR, "not enough wait_address slots\n");
377 return;
378 }
379
380 m->poll_waddr[i] = wait_address;
381
382 if (!wait_address) {
383 dprintk(DEBUG_ERROR, "no wait_address\n");
384 m->poll_waddr[i] = ERR_PTR(-EIO);
385 return;
386 }
387
388 init_waitqueue_entry(&m->poll_wait[i], m->poll_task->task);
389 add_wait_queue(wait_address, &m->poll_wait[i]);
390 }
391
392 /**
393 * v9fs_poll_mux - polls a mux and schedules read or write works if necessary
394 */
395 static void v9fs_poll_mux(struct v9fs_mux_data *m)
396 {
397 int n;
398
399 if (m->err < 0)
400 return;
401
402 n = m->trans->poll(m->trans, NULL);
403 if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) {
404 dprintk(DEBUG_MUX, "error mux %p err %d\n", m, n);
405 if (n >= 0)
406 n = -ECONNRESET;
407 v9fs_mux_cancel(m, n);
408 }
409
410 if (n & POLLIN) {
411 set_bit(Rpending, &m->wsched);
412 dprintk(DEBUG_MUX, "mux %p can read\n", m);
413 if (!test_and_set_bit(Rworksched, &m->wsched)) {
414 dprintk(DEBUG_MUX, "schedule read work mux %p\n", m);
415 queue_work(v9fs_mux_wq, &m->rq);
416 }
417 }
418
419 if (n & POLLOUT) {
420 set_bit(Wpending, &m->wsched);
421 dprintk(DEBUG_MUX, "mux %p can write\n", m);
422 if ((m->wsize || !list_empty(&m->unsent_req_list))
423 && !test_and_set_bit(Wworksched, &m->wsched)) {
424 dprintk(DEBUG_MUX, "schedule write work mux %p\n", m);
425 queue_work(v9fs_mux_wq, &m->wq);
426 }
427 }
428 }
429
430 /**
431 * v9fs_poll_proc - polls all v9fs transports for new events and queues
432 * the appropriate work to the work queue
433 */
434 static int v9fs_poll_proc(void *a)
435 {
436 struct v9fs_mux_data *m, *mtmp;
437 struct v9fs_mux_poll_task *vpt;
438
439 vpt = a;
440 dprintk(DEBUG_MUX, "start %p %p\n", current, vpt);
441 while (!kthread_should_stop()) {
442 set_current_state(TASK_INTERRUPTIBLE);
443
444 list_for_each_entry_safe(m, mtmp, &vpt->mux_list, mux_list) {
445 v9fs_poll_mux(m);
446 }
447
448 dprintk(DEBUG_MUX, "sleeping...\n");
449 schedule_timeout(SCHED_TIMEOUT * HZ);
450 }
451
452 __set_current_state(TASK_RUNNING);
453 dprintk(DEBUG_MUX, "finish\n");
454 return 0;
455 }
456
457 /**
458 * v9fs_write_work - called when a transport can send some data
459 */
460 static void v9fs_write_work(struct work_struct *work)
461 {
462 int n, err;
463 struct v9fs_mux_data *m;
464 struct v9fs_req *req;
465
466 m = container_of(work, struct v9fs_mux_data, wq);
467
468 if (m->err < 0) {
469 clear_bit(Wworksched, &m->wsched);
470 return;
471 }
472
473 if (!m->wsize) {
474 if (list_empty(&m->unsent_req_list)) {
475 clear_bit(Wworksched, &m->wsched);
476 return;
477 }
478
479 spin_lock(&m->lock);
480 again:
481 req = list_entry(m->unsent_req_list.next, struct v9fs_req,
482 req_list);
483 list_move_tail(&req->req_list, &m->req_list);
484 if (req->err == ERREQFLUSH)
485 goto again;
486
487 m->wbuf = req->tcall->sdata;
488 m->wsize = req->tcall->size;
489 m->wpos = 0;
490 dump_data(m->wbuf, m->wsize);
491 spin_unlock(&m->lock);
492 }
493
494 dprintk(DEBUG_MUX, "mux %p pos %d size %d\n", m, m->wpos, m->wsize);
495 clear_bit(Wpending, &m->wsched);
496 err = m->trans->write(m->trans, m->wbuf + m->wpos, m->wsize - m->wpos);
497 dprintk(DEBUG_MUX, "mux %p sent %d bytes\n", m, err);
498 if (err == -EAGAIN) {
499 clear_bit(Wworksched, &m->wsched);
500 return;
501 }
502
503 if (err <= 0)
504 goto error;
505
506 m->wpos += err;
507 if (m->wpos == m->wsize)
508 m->wpos = m->wsize = 0;
509
510 if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
511 if (test_and_clear_bit(Wpending, &m->wsched))
512 n = POLLOUT;
513 else
514 n = m->trans->poll(m->trans, NULL);
515
516 if (n & POLLOUT) {
517 dprintk(DEBUG_MUX, "schedule write work mux %p\n", m);
518 queue_work(v9fs_mux_wq, &m->wq);
519 } else
520 clear_bit(Wworksched, &m->wsched);
521 } else
522 clear_bit(Wworksched, &m->wsched);
523
524 return;
525
526 error:
527 v9fs_mux_cancel(m, err);
528 clear_bit(Wworksched, &m->wsched);
529 }
530
531 static void process_request(struct v9fs_mux_data *m, struct v9fs_req *req)
532 {
533 int ecode;
534 struct v9fs_str *ename;
535
536 if (!req->err && req->rcall->id == RERROR) {
537 ecode = req->rcall->params.rerror.errno;
538 ename = &req->rcall->params.rerror.error;
539
540 dprintk(DEBUG_MUX, "Rerror %.*s\n", ename->len, ename->str);
541
542 if (*m->extended)
543 req->err = -ecode;
544
545 if (!req->err) {
546 req->err = v9fs_errstr2errno(ename->str, ename->len);
547
548 if (!req->err) { /* string match failed */
549 PRINT_FCALL_ERROR("unknown error", req->rcall);
550 }
551
552 if (!req->err)
553 req->err = -ESERVERFAULT;
554 }
555 } else if (req->tcall && req->rcall->id != req->tcall->id + 1) {
556 dprintk(DEBUG_ERROR, "fcall mismatch: expected %d, got %d\n",
557 req->tcall->id + 1, req->rcall->id);
558 if (!req->err)
559 req->err = -EIO;
560 }
561 }
562
563 /**
564 * v9fs_read_work - called when there is some data to be read from a transport
565 */
566 static void v9fs_read_work(struct work_struct *work)
567 {
568 int n, err;
569 struct v9fs_mux_data *m;
570 struct v9fs_req *req, *rptr, *rreq;
571 struct v9fs_fcall *rcall;
572 char *rbuf;
573
574 m = container_of(work, struct v9fs_mux_data, rq);
575
576 if (m->err < 0)
577 return;
578
579 rcall = NULL;
580 dprintk(DEBUG_MUX, "start mux %p pos %d\n", m, m->rpos);
581
582 if (!m->rcall) {
583 m->rcall =
584 kmalloc(sizeof(struct v9fs_fcall) + m->msize, GFP_KERNEL);
585 if (!m->rcall) {
586 err = -ENOMEM;
587 goto error;
588 }
589
590 m->rbuf = (char *)m->rcall + sizeof(struct v9fs_fcall);
591 m->rpos = 0;
592 }
593
594 clear_bit(Rpending, &m->wsched);
595 err = m->trans->read(m->trans, m->rbuf + m->rpos, m->msize - m->rpos);
596 dprintk(DEBUG_MUX, "mux %p got %d bytes\n", m, err);
597 if (err == -EAGAIN) {
598 clear_bit(Rworksched, &m->wsched);
599 return;
600 }
601
602 if (err <= 0)
603 goto error;
604
605 m->rpos += err;
606 while (m->rpos > 4) {
607 n = le32_to_cpu(*(__le32 *) m->rbuf);
608 if (n >= m->msize) {
609 dprintk(DEBUG_ERROR,
610 "requested packet size too big: %d\n", n);
611 err = -EIO;
612 goto error;
613 }
614
615 if (m->rpos < n)
616 break;
617
618 dump_data(m->rbuf, n);
619 err =
620 v9fs_deserialize_fcall(m->rbuf, n, m->rcall, *m->extended);
621 if (err < 0) {
622 goto error;
623 }
624
625 if ((v9fs_debug_level&DEBUG_FCALL) == DEBUG_FCALL) {
626 char buf[150];
627
628 v9fs_printfcall(buf, sizeof(buf), m->rcall,
629 *m->extended);
630 printk(KERN_NOTICE ">>> %p %s\n", m, buf);
631 }
632
633 rcall = m->rcall;
634 rbuf = m->rbuf;
635 if (m->rpos > n) {
636 m->rcall = kmalloc(sizeof(struct v9fs_fcall) + m->msize,
637 GFP_KERNEL);
638 if (!m->rcall) {
639 err = -ENOMEM;
640 goto error;
641 }
642
643 m->rbuf = (char *)m->rcall + sizeof(struct v9fs_fcall);
644 memmove(m->rbuf, rbuf + n, m->rpos - n);
645 m->rpos -= n;
646 } else {
647 m->rcall = NULL;
648 m->rbuf = NULL;
649 m->rpos = 0;
650 }
651
652 dprintk(DEBUG_MUX, "mux %p fcall id %d tag %d\n", m, rcall->id,
653 rcall->tag);
654
655 req = NULL;
656 spin_lock(&m->lock);
657 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
658 if (rreq->tag == rcall->tag) {
659 req = rreq;
660 if (req->flush != Flushing)
661 list_del(&req->req_list);
662 break;
663 }
664 }
665 spin_unlock(&m->lock);
666
667 if (req) {
668 req->rcall = rcall;
669 process_request(m, req);
670
671 if (req->flush != Flushing) {
672 if (req->cb)
673 (*req->cb) (req, req->cba);
674 else
675 kfree(req->rcall);
676
677 wake_up(&m->equeue);
678 }
679 } else {
680 if (err >= 0 && rcall->id != RFLUSH)
681 dprintk(DEBUG_ERROR,
682 "unexpected response mux %p id %d tag %d\n",
683 m, rcall->id, rcall->tag);
684 kfree(rcall);
685 }
686 }
687
688 if (!list_empty(&m->req_list)) {
689 if (test_and_clear_bit(Rpending, &m->wsched))
690 n = POLLIN;
691 else
692 n = m->trans->poll(m->trans, NULL);
693
694 if (n & POLLIN) {
695 dprintk(DEBUG_MUX, "schedule read work mux %p\n", m);
696 queue_work(v9fs_mux_wq, &m->rq);
697 } else
698 clear_bit(Rworksched, &m->wsched);
699 } else
700 clear_bit(Rworksched, &m->wsched);
701
702 return;
703
704 error:
705 v9fs_mux_cancel(m, err);
706 clear_bit(Rworksched, &m->wsched);
707 }
708
709 /**
710 * v9fs_send_request - send 9P request
711 * The function can sleep until the request is scheduled for sending.
712 * The function can be interrupted. Return from the function is not
713 * a guarantee that the request is sent successfully. Can return errors
714 * that can be retrieved by PTR_ERR macros.
715 *
716 * @m: mux data
717 * @tc: request to be sent
718 * @cb: callback function to call when response is received
719 * @cba: parameter to pass to the callback function
720 */
721 static struct v9fs_req *v9fs_send_request(struct v9fs_mux_data *m,
722 struct v9fs_fcall *tc,
723 v9fs_mux_req_callback cb, void *cba)
724 {
725 int n;
726 struct v9fs_req *req;
727
728 dprintk(DEBUG_MUX, "mux %p task %p tcall %p id %d\n", m, current,
729 tc, tc->id);
730 if (m->err < 0)
731 return ERR_PTR(m->err);
732
733 req = kmalloc(sizeof(struct v9fs_req), GFP_KERNEL);
734 if (!req)
735 return ERR_PTR(-ENOMEM);
736
737 if (tc->id == TVERSION)
738 n = V9FS_NOTAG;
739 else
740 n = v9fs_mux_get_tag(m);
741
742 if (n < 0)
743 return ERR_PTR(-ENOMEM);
744
745 v9fs_set_tag(tc, n);
746 if ((v9fs_debug_level&DEBUG_FCALL) == DEBUG_FCALL) {
747 char buf[150];
748
749 v9fs_printfcall(buf, sizeof(buf), tc, *m->extended);
750 printk(KERN_NOTICE "<<< %p %s\n", m, buf);
751 }
752
753 spin_lock_init(&req->lock);
754 req->tag = n;
755 req->tcall = tc;
756 req->rcall = NULL;
757 req->err = 0;
758 req->cb = cb;
759 req->cba = cba;
760 req->flush = None;
761
762 spin_lock(&m->lock);
763 list_add_tail(&req->req_list, &m->unsent_req_list);
764 spin_unlock(&m->lock);
765
766 if (test_and_clear_bit(Wpending, &m->wsched))
767 n = POLLOUT;
768 else
769 n = m->trans->poll(m->trans, NULL);
770
771 if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
772 queue_work(v9fs_mux_wq, &m->wq);
773
774 return req;
775 }
776
777 static void v9fs_mux_free_request(struct v9fs_mux_data *m, struct v9fs_req *req)
778 {
779 v9fs_mux_put_tag(m, req->tag);
780 kfree(req);
781 }
782
783 static void v9fs_mux_flush_cb(struct v9fs_req *freq, void *a)
784 {
785 v9fs_mux_req_callback cb;
786 int tag;
787 struct v9fs_mux_data *m;
788 struct v9fs_req *req, *rreq, *rptr;
789
790 m = a;
791 dprintk(DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
792 freq->tcall, freq->rcall, freq->err,
793 freq->tcall->params.tflush.oldtag);
794
795 spin_lock(&m->lock);
796 cb = NULL;
797 tag = freq->tcall->params.tflush.oldtag;
798 req = NULL;
799 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
800 if (rreq->tag == tag) {
801 req = rreq;
802 list_del(&req->req_list);
803 break;
804 }
805 }
806 spin_unlock(&m->lock);
807
808 if (req) {
809 spin_lock(&req->lock);
810 req->flush = Flushed;
811 spin_unlock(&req->lock);
812
813 if (req->cb)
814 (*req->cb) (req, req->cba);
815 else
816 kfree(req->rcall);
817
818 wake_up(&m->equeue);
819 }
820
821 kfree(freq->tcall);
822 kfree(freq->rcall);
823 v9fs_mux_free_request(m, freq);
824 }
825
826 static int
827 v9fs_mux_flush_request(struct v9fs_mux_data *m, struct v9fs_req *req)
828 {
829 struct v9fs_fcall *fc;
830 struct v9fs_req *rreq, *rptr;
831
832 dprintk(DEBUG_MUX, "mux %p req %p tag %d\n", m, req, req->tag);
833
834 /* if a response was received for a request, do nothing */
835 spin_lock(&req->lock);
836 if (req->rcall || req->err) {
837 spin_unlock(&req->lock);
838 dprintk(DEBUG_MUX, "mux %p req %p response already received\n", m, req);
839 return 0;
840 }
841
842 req->flush = Flushing;
843 spin_unlock(&req->lock);
844
845 spin_lock(&m->lock);
846 /* if the request is not sent yet, just remove it from the list */
847 list_for_each_entry_safe(rreq, rptr, &m->unsent_req_list, req_list) {
848 if (rreq->tag == req->tag) {
849 dprintk(DEBUG_MUX, "mux %p req %p request is not sent yet\n", m, req);
850 list_del(&rreq->req_list);
851 req->flush = Flushed;
852 spin_unlock(&m->lock);
853 if (req->cb)
854 (*req->cb) (req, req->cba);
855 return 0;
856 }
857 }
858 spin_unlock(&m->lock);
859
860 clear_thread_flag(TIF_SIGPENDING);
861 fc = v9fs_create_tflush(req->tag);
862 v9fs_send_request(m, fc, v9fs_mux_flush_cb, m);
863 return 1;
864 }
865
866 static void
867 v9fs_mux_rpc_cb(struct v9fs_req *req, void *a)
868 {
869 struct v9fs_mux_rpc *r;
870
871 dprintk(DEBUG_MUX, "req %p r %p\n", req, a);
872 r = a;
873 r->rcall = req->rcall;
874 r->err = req->err;
875
876 if (req->flush!=None && !req->err)
877 r->err = -ERESTARTSYS;
878
879 wake_up(&r->wqueue);
880 }
881
882 /**
883 * v9fs_mux_rpc - sends 9P request and waits until a response is available.
884 * The function can be interrupted.
885 * @m: mux data
886 * @tc: request to be sent
887 * @rc: pointer where a pointer to the response is stored
888 */
889 int
890 v9fs_mux_rpc(struct v9fs_mux_data *m, struct v9fs_fcall *tc,
891 struct v9fs_fcall **rc)
892 {
893 int err, sigpending;
894 unsigned long flags;
895 struct v9fs_req *req;
896 struct v9fs_mux_rpc r;
897
898 r.err = 0;
899 r.tcall = tc;
900 r.rcall = NULL;
901 r.m = m;
902 init_waitqueue_head(&r.wqueue);
903
904 if (rc)
905 *rc = NULL;
906
907 sigpending = 0;
908 if (signal_pending(current)) {
909 sigpending = 1;
910 clear_thread_flag(TIF_SIGPENDING);
911 }
912
913 req = v9fs_send_request(m, tc, v9fs_mux_rpc_cb, &r);
914 if (IS_ERR(req)) {
915 err = PTR_ERR(req);
916 dprintk(DEBUG_MUX, "error %d\n", err);
917 return err;
918 }
919
920 err = wait_event_interruptible(r.wqueue, r.rcall != NULL || r.err < 0);
921 if (r.err < 0)
922 err = r.err;
923
924 if (err == -ERESTARTSYS && m->trans->status == Connected && m->err == 0) {
925 if (v9fs_mux_flush_request(m, req)) {
926 /* wait until we get response of the flush message */
927 do {
928 clear_thread_flag(TIF_SIGPENDING);
929 err = wait_event_interruptible(r.wqueue,
930 r.rcall || r.err);
931 } while (!r.rcall && !r.err && err==-ERESTARTSYS &&
932 m->trans->status==Connected && !m->err);
933
934 err = -ERESTARTSYS;
935 }
936 sigpending = 1;
937 }
938
939 if (sigpending) {
940 spin_lock_irqsave(&current->sighand->siglock, flags);
941 recalc_sigpending();
942 spin_unlock_irqrestore(&current->sighand->siglock, flags);
943 }
944
945 if (rc)
946 *rc = r.rcall;
947 else
948 kfree(r.rcall);
949
950 v9fs_mux_free_request(m, req);
951 if (err > 0)
952 err = -EIO;
953
954 return err;
955 }
956
957 #if 0
958 /**
959 * v9fs_mux_rpcnb - sends 9P request without waiting for response.
960 * @m: mux data
961 * @tc: request to be sent
962 * @cb: callback function to be called when response arrives
963 * @cba: value to pass to the callback function
964 */
965 int v9fs_mux_rpcnb(struct v9fs_mux_data *m, struct v9fs_fcall *tc,
966 v9fs_mux_req_callback cb, void *a)
967 {
968 int err;
969 struct v9fs_req *req;
970
971 req = v9fs_send_request(m, tc, cb, a);
972 if (IS_ERR(req)) {
973 err = PTR_ERR(req);
974 dprintk(DEBUG_MUX, "error %d\n", err);
975 return PTR_ERR(req);
976 }
977
978 dprintk(DEBUG_MUX, "mux %p tc %p tag %d\n", m, tc, req->tag);
979 return 0;
980 }
981 #endif /* 0 */
982
983 /**
984 * v9fs_mux_cancel - cancel all pending requests with error
985 * @m: mux data
986 * @err: error code
987 */
988 void v9fs_mux_cancel(struct v9fs_mux_data *m, int err)
989 {
990 struct v9fs_req *req, *rtmp;
991 LIST_HEAD(cancel_list);
992
993 dprintk(DEBUG_ERROR, "mux %p err %d\n", m, err);
994 m->err = err;
995 spin_lock(&m->lock);
996 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
997 list_move(&req->req_list, &cancel_list);
998 }
999 list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
1000 list_move(&req->req_list, &cancel_list);
1001 }
1002 spin_unlock(&m->lock);
1003
1004 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
1005 list_del(&req->req_list);
1006 if (!req->err)
1007 req->err = err;
1008
1009 if (req->cb)
1010 (*req->cb) (req, req->cba);
1011 else
1012 kfree(req->rcall);
1013 }
1014
1015 wake_up(&m->equeue);
1016 }
1017
1018 static u16 v9fs_mux_get_tag(struct v9fs_mux_data *m)
1019 {
1020 int tag;
1021
1022 tag = v9fs_get_idpool(&m->tagpool);
1023 if (tag < 0)
1024 return V9FS_NOTAG;
1025 else
1026 return (u16) tag;
1027 }
1028
1029 static void v9fs_mux_put_tag(struct v9fs_mux_data *m, u16 tag)
1030 {
1031 if (tag != V9FS_NOTAG && v9fs_check_idpool(tag, &m->tagpool))
1032 v9fs_put_idpool(tag, &m->tagpool);
1033 }
Linux kernel - Deliverables
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