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Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc-merge
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / 9p / mux.c
blob945cb368d451948156bf518ee7e40616ac09e675
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 as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to:
21 * Free Software Foundation
22 * 51 Franklin Street, Fifth Floor
23 * Boston, MA 02111-1301 USA
24 *
25 */
26
27 #include <linux/config.h>
28 #include <linux/module.h>
29 #include <linux/errno.h>
30 #include <linux/fs.h>
31 #include <linux/poll.h>
32 #include <linux/kthread.h>
33 #include <linux/idr.h>
34
35 #include "debug.h"
36 #include "v9fs.h"
37 #include "9p.h"
38 #include "conv.h"
39 #include "transport.h"
40 #include "mux.h"
41
42 #define ERREQFLUSH 1
43 #define SCHED_TIMEOUT 10
44 #define MAXPOLLWADDR 2
45
46 enum {
47 Rworksched = 1, /* read work scheduled or running */
48 Rpending = 2, /* can read */
49 Wworksched = 4, /* write work scheduled or running */
50 Wpending = 8, /* can write */
51 };
52
53 struct v9fs_mux_poll_task;
54
55 struct v9fs_req {
56 int tag;
57 struct v9fs_fcall *tcall;
58 struct v9fs_fcall *rcall;
59 int err;
60 v9fs_mux_req_callback cb;
61 void *cba;
62 struct list_head req_list;
63 };
64
65 struct v9fs_mux_data {
66 spinlock_t lock;
67 struct list_head mux_list;
68 struct v9fs_mux_poll_task *poll_task;
69 int msize;
70 unsigned char *extended;
71 struct v9fs_transport *trans;
72 struct v9fs_idpool tidpool;
73 int err;
74 wait_queue_head_t equeue;
75 struct list_head req_list;
76 struct list_head unsent_req_list;
77 struct v9fs_fcall *rcall;
78 int rpos;
79 char *rbuf;
80 int wpos;
81 int wsize;
82 char *wbuf;
83 wait_queue_t poll_wait[MAXPOLLWADDR];
84 wait_queue_head_t *poll_waddr[MAXPOLLWADDR];
85 poll_table pt;
86 struct work_struct rq;
87 struct work_struct wq;
88 unsigned long wsched;
89 };
90
91 struct v9fs_mux_poll_task {
92 struct task_struct *task;
93 struct list_head mux_list;
94 int muxnum;
95 };
96
97 struct v9fs_mux_rpc {
98 struct v9fs_mux_data *m;
99 struct v9fs_req *req;
100 int err;
101 struct v9fs_fcall *rcall;
102 wait_queue_head_t wqueue;
103 };
104
105 static int v9fs_poll_proc(void *);
106 static void v9fs_read_work(void *);
107 static void v9fs_write_work(void *);
108 static void v9fs_pollwait(struct file *filp, wait_queue_head_t * wait_address,
109 poll_table * p);
110 static u16 v9fs_mux_get_tag(struct v9fs_mux_data *);
111 static void v9fs_mux_put_tag(struct v9fs_mux_data *, u16);
112
113 static DECLARE_MUTEX(v9fs_mux_task_lock);
114 static struct workqueue_struct *v9fs_mux_wq;
115
116 static int v9fs_mux_num;
117 static int v9fs_mux_poll_task_num;
118 static struct v9fs_mux_poll_task v9fs_mux_poll_tasks[100];
119
120 int v9fs_mux_global_init(void)
121 {
122 int i;
123
124 for (i = 0; i < ARRAY_SIZE(v9fs_mux_poll_tasks); i++)
125 v9fs_mux_poll_tasks[i].task = NULL;
126
127 v9fs_mux_wq = create_workqueue("v9fs");
128 if (!v9fs_mux_wq)
129 return -ENOMEM;
130
131 return 0;
132 }
133
134 void v9fs_mux_global_exit(void)
135 {
136 destroy_workqueue(v9fs_mux_wq);
137 }
138
139 /**
140 * v9fs_mux_calc_poll_procs - calculates the number of polling procs
141 * based on the number of mounted v9fs filesystems.
142 *
143 * The current implementation returns sqrt of the number of mounts.
144 */
145 inline int v9fs_mux_calc_poll_procs(int muxnum)
146 {
147 int n;
148
149 if (v9fs_mux_poll_task_num)
150 n = muxnum / v9fs_mux_poll_task_num +
151 (muxnum % v9fs_mux_poll_task_num ? 1 : 0);
152 else
153 n = 1;
154
155 if (n > ARRAY_SIZE(v9fs_mux_poll_tasks))
156 n = ARRAY_SIZE(v9fs_mux_poll_tasks);
157
158 return n;
159 }
160
161 static int v9fs_mux_poll_start(struct v9fs_mux_data *m)
162 {
163 int i, n;
164 struct v9fs_mux_poll_task *vpt, *vptlast;
165 struct task_struct *pproc;
166
167 dprintk(DEBUG_MUX, "mux %p muxnum %d procnum %d\n", m, v9fs_mux_num,
168 v9fs_mux_poll_task_num);
169 up(&v9fs_mux_task_lock);
170
171 n = v9fs_mux_calc_poll_procs(v9fs_mux_num + 1);
172 if (n > v9fs_mux_poll_task_num) {
173 for (i = 0; i < ARRAY_SIZE(v9fs_mux_poll_tasks); i++) {
174 if (v9fs_mux_poll_tasks[i].task == NULL) {
175 vpt = &v9fs_mux_poll_tasks[i];
176 dprintk(DEBUG_MUX, "create proc %p\n", vpt);
177 pproc = kthread_create(v9fs_poll_proc, vpt,
178 "v9fs-poll");
179
180 if (!IS_ERR(pproc)) {
181 vpt->task = pproc;
182 INIT_LIST_HEAD(&vpt->mux_list);
183 vpt->muxnum = 0;
184 v9fs_mux_poll_task_num++;
185 wake_up_process(vpt->task);
186 }
187 break;
188 }
189 }
190
191 if (i >= ARRAY_SIZE(v9fs_mux_poll_tasks))
192 dprintk(DEBUG_ERROR, "warning: no free poll slots\n");
193 }
194
195 n = (v9fs_mux_num + 1) / v9fs_mux_poll_task_num +
196 ((v9fs_mux_num + 1) % v9fs_mux_poll_task_num ? 1 : 0);
197
198 vptlast = NULL;
199 for (i = 0; i < ARRAY_SIZE(v9fs_mux_poll_tasks); i++) {
200 vpt = &v9fs_mux_poll_tasks[i];
201 if (vpt->task != NULL) {
202 vptlast = vpt;
203 if (vpt->muxnum < n) {
204 dprintk(DEBUG_MUX, "put in proc %d\n", i);
205 list_add(&m->mux_list, &vpt->mux_list);
206 vpt->muxnum++;
207 m->poll_task = vpt;
208 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
209 init_poll_funcptr(&m->pt, v9fs_pollwait);
210 break;
211 }
212 }
213 }
214
215 if (i >= ARRAY_SIZE(v9fs_mux_poll_tasks)) {
216 if (vptlast == NULL)
217 return -ENOMEM;
218
219 dprintk(DEBUG_MUX, "put in proc %d\n", i);
220 list_add(&m->mux_list, &vptlast->mux_list);
221 vptlast->muxnum++;
222 m->poll_task = vptlast;
223 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
224 init_poll_funcptr(&m->pt, v9fs_pollwait);
225 }
226
227 v9fs_mux_num++;
228 down(&v9fs_mux_task_lock);
229
230 return 0;
231 }
232
233 static void v9fs_mux_poll_stop(struct v9fs_mux_data *m)
234 {
235 int i;
236 struct v9fs_mux_poll_task *vpt;
237
238 up(&v9fs_mux_task_lock);
239 vpt = m->poll_task;
240 list_del(&m->mux_list);
241 for(i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
242 if (m->poll_waddr[i] != NULL) {
243 remove_wait_queue(m->poll_waddr[i], &m->poll_wait[i]);
244 m->poll_waddr[i] = NULL;
245 }
246 }
247 vpt->muxnum--;
248 if (!vpt->muxnum) {
249 dprintk(DEBUG_MUX, "destroy proc %p\n", vpt);
250 send_sig(SIGKILL, vpt->task, 1);
251 vpt->task = NULL;
252 v9fs_mux_poll_task_num--;
253 }
254 v9fs_mux_num--;
255 down(&v9fs_mux_task_lock);
256 }
257
258 /**
259 * v9fs_mux_init - allocate and initialize the per-session mux data
260 * Creates the polling task if this is the first session.
261 *
262 * @trans - transport structure
263 * @msize - maximum message size
264 * @extended - pointer to the extended flag
265 */
266 struct v9fs_mux_data *v9fs_mux_init(struct v9fs_transport *trans, int msize,
267 unsigned char *extended)
268 {
269 int i, n;
270 struct v9fs_mux_data *m, *mtmp;
271
272 dprintk(DEBUG_MUX, "transport %p msize %d\n", trans, msize);
273 m = kmalloc(sizeof(struct v9fs_mux_data), GFP_KERNEL);
274 if (!m)
275 return ERR_PTR(-ENOMEM);
276
277 spin_lock_init(&m->lock);
278 INIT_LIST_HEAD(&m->mux_list);
279 m->msize = msize;
280 m->extended = extended;
281 m->trans = trans;
282 idr_init(&m->tidpool.pool);
283 init_MUTEX(&m->tidpool.lock);
284 m->err = 0;
285 init_waitqueue_head(&m->equeue);
286 INIT_LIST_HEAD(&m->req_list);
287 INIT_LIST_HEAD(&m->unsent_req_list);
288 m->rcall = NULL;
289 m->rpos = 0;
290 m->rbuf = NULL;
291 m->wpos = m->wsize = 0;
292 m->wbuf = NULL;
293 INIT_WORK(&m->rq, v9fs_read_work, m);
294 INIT_WORK(&m->wq, v9fs_write_work, m);
295 m->wsched = 0;
296 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
297 m->poll_task = NULL;
298 n = v9fs_mux_poll_start(m);
299 if (n)
300 return ERR_PTR(n);
301
302 n = trans->poll(trans, &m->pt);
303 if (n & POLLIN) {
304 dprintk(DEBUG_MUX, "mux %p can read\n", m);
305 set_bit(Rpending, &m->wsched);
306 }
307
308 if (n & POLLOUT) {
309 dprintk(DEBUG_MUX, "mux %p can write\n", m);
310 set_bit(Wpending, &m->wsched);
311 }
312
313 for(i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
314 if (IS_ERR(m->poll_waddr[i])) {
315 v9fs_mux_poll_stop(m);
316 mtmp = (void *)m->poll_waddr; /* the error code */
317 kfree(m);
318 m = mtmp;
319 break;
320 }
321 }
322
323 return m;
324 }
325
326 /**
327 * v9fs_mux_destroy - cancels all pending requests and frees mux resources
328 */
329 void v9fs_mux_destroy(struct v9fs_mux_data *m)
330 {
331 dprintk(DEBUG_MUX, "mux %p prev %p next %p\n", m,
332 m->mux_list.prev, m->mux_list.next);
333 v9fs_mux_cancel(m, -ECONNRESET);
334
335 if (!list_empty(&m->req_list)) {
336 /* wait until all processes waiting on this session exit */
337 dprintk(DEBUG_MUX, "mux %p waiting for empty request queue\n",
338 m);
339 wait_event_timeout(m->equeue, (list_empty(&m->req_list)), 5000);
340 dprintk(DEBUG_MUX, "mux %p request queue empty: %d\n", m,
341 list_empty(&m->req_list));
342 }
343
344 v9fs_mux_poll_stop(m);
345 m->trans = NULL;
346
347 kfree(m);
348 }
349
350 /**
351 * v9fs_pollwait - called by files poll operation to add v9fs-poll task
352 * to files wait queue
353 */
354 static void
355 v9fs_pollwait(struct file *filp, wait_queue_head_t * wait_address,
356 poll_table * p)
357 {
358 int i;
359 struct v9fs_mux_data *m;
360
361 m = container_of(p, struct v9fs_mux_data, pt);
362 for(i = 0; i < ARRAY_SIZE(m->poll_waddr); i++)
363 if (m->poll_waddr[i] == NULL)
364 break;
365
366 if (i >= ARRAY_SIZE(m->poll_waddr)) {
367 dprintk(DEBUG_ERROR, "not enough wait_address slots\n");
368 return;
369 }
370
371 m->poll_waddr[i] = wait_address;
372
373 if (!wait_address) {
374 dprintk(DEBUG_ERROR, "no wait_address\n");
375 m->poll_waddr[i] = ERR_PTR(-EIO);
376 return;
377 }
378
379 init_waitqueue_entry(&m->poll_wait[i], m->poll_task->task);
380 add_wait_queue(wait_address, &m->poll_wait[i]);
381 }
382
383 /**
384 * v9fs_poll_mux - polls a mux and schedules read or write works if necessary
385 */
386 static inline void v9fs_poll_mux(struct v9fs_mux_data *m)
387 {
388 int n;
389
390 if (m->err < 0)
391 return;
392
393 n = m->trans->poll(m->trans, NULL);
394 if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) {
395 dprintk(DEBUG_MUX, "error mux %p err %d\n", m, n);
396 if (n >= 0)
397 n = -ECONNRESET;
398 v9fs_mux_cancel(m, n);
399 }
400
401 if (n & POLLIN) {
402 set_bit(Rpending, &m->wsched);
403 dprintk(DEBUG_MUX, "mux %p can read\n", m);
404 if (!test_and_set_bit(Rworksched, &m->wsched)) {
405 dprintk(DEBUG_MUX, "schedule read work mux %p\n", m);
406 queue_work(v9fs_mux_wq, &m->rq);
407 }
408 }
409
410 if (n & POLLOUT) {
411 set_bit(Wpending, &m->wsched);
412 dprintk(DEBUG_MUX, "mux %p can write\n", m);
413 if ((m->wsize || !list_empty(&m->unsent_req_list))
414 && !test_and_set_bit(Wworksched, &m->wsched)) {
415 dprintk(DEBUG_MUX, "schedule write work mux %p\n", m);
416 queue_work(v9fs_mux_wq, &m->wq);
417 }
418 }
419 }
420
421 /**
422 * v9fs_poll_proc - polls all v9fs transports for new events and queues
423 * the appropriate work to the work queue
424 */
425 static int v9fs_poll_proc(void *a)
426 {
427 struct v9fs_mux_data *m, *mtmp;
428 struct v9fs_mux_poll_task *vpt;
429
430 vpt = a;
431 dprintk(DEBUG_MUX, "start %p %p\n", current, vpt);
432 allow_signal(SIGKILL);
433 while (!kthread_should_stop()) {
434 set_current_state(TASK_INTERRUPTIBLE);
435 if (signal_pending(current))
436 break;
437
438 list_for_each_entry_safe(m, mtmp, &vpt->mux_list, mux_list) {
439 v9fs_poll_mux(m);
440 }
441
442 dprintk(DEBUG_MUX, "sleeping...\n");
443 schedule_timeout(SCHED_TIMEOUT * HZ);
444 }
445
446 __set_current_state(TASK_RUNNING);
447 dprintk(DEBUG_MUX, "finish\n");
448 return 0;
449 }
450
451 /**
452 * v9fs_write_work - called when a transport can send some data
453 */
454 static void v9fs_write_work(void *a)
455 {
456 int n, err;
457 struct v9fs_mux_data *m;
458 struct v9fs_req *req;
459
460 m = a;
461
462 if (m->err < 0) {
463 clear_bit(Wworksched, &m->wsched);
464 return;
465 }
466
467 if (!m->wsize) {
468 if (list_empty(&m->unsent_req_list)) {
469 clear_bit(Wworksched, &m->wsched);
470 return;
471 }
472
473 spin_lock(&m->lock);
474 req =
475 list_entry(m->unsent_req_list.next, struct v9fs_req,
476 req_list);
477 list_move_tail(&req->req_list, &m->req_list);
478 m->wbuf = req->tcall->sdata;
479 m->wsize = req->tcall->size;
480 m->wpos = 0;
481 dump_data(m->wbuf, m->wsize);
482 spin_unlock(&m->lock);
483 }
484
485 dprintk(DEBUG_MUX, "mux %p pos %d size %d\n", m, m->wpos, m->wsize);
486 clear_bit(Wpending, &m->wsched);
487 err = m->trans->write(m->trans, m->wbuf + m->wpos, m->wsize - m->wpos);
488 dprintk(DEBUG_MUX, "mux %p sent %d bytes\n", m, err);
489 if (err == -EAGAIN) {
490 clear_bit(Wworksched, &m->wsched);
491 return;
492 }
493
494 if (err <= 0)
495 goto error;
496
497 m->wpos += err;
498 if (m->wpos == m->wsize)
499 m->wpos = m->wsize = 0;
500
501 if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
502 if (test_and_clear_bit(Wpending, &m->wsched))
503 n = POLLOUT;
504 else
505 n = m->trans->poll(m->trans, NULL);
506
507 if (n & POLLOUT) {
508 dprintk(DEBUG_MUX, "schedule write work mux %p\n", m);
509 queue_work(v9fs_mux_wq, &m->wq);
510 } else
511 clear_bit(Wworksched, &m->wsched);
512 } else
513 clear_bit(Wworksched, &m->wsched);
514
515 return;
516
517 error:
518 v9fs_mux_cancel(m, err);
519 clear_bit(Wworksched, &m->wsched);
520 }
521
522 static void process_request(struct v9fs_mux_data *m, struct v9fs_req *req)
523 {
524 int ecode, tag;
525 struct v9fs_str *ename;
526
527 tag = req->tag;
528 if (req->rcall->id == RERROR && !req->err) {
529 ecode = req->rcall->params.rerror.errno;
530 ename = &req->rcall->params.rerror.error;
531
532 dprintk(DEBUG_MUX, "Rerror %.*s\n", ename->len, ename->str);
533
534 if (*m->extended)
535 req->err = -ecode;
536
537 if (!req->err) {
538 req->err = v9fs_errstr2errno(ename->str, ename->len);
539
540 if (!req->err) { /* string match failed */
541 PRINT_FCALL_ERROR("unknown error", req->rcall);
542 }
543
544 if (!req->err)
545 req->err = -ESERVERFAULT;
546 }
547 } else if (req->tcall && req->rcall->id != req->tcall->id + 1) {
548 dprintk(DEBUG_ERROR, "fcall mismatch: expected %d, got %d\n",
549 req->tcall->id + 1, req->rcall->id);
550 if (!req->err)
551 req->err = -EIO;
552 }
553
554 if (req->cb && req->err != ERREQFLUSH) {
555 dprintk(DEBUG_MUX, "calling callback tcall %p rcall %p\n",
556 req->tcall, req->rcall);
557
558 (*req->cb) (req->cba, req->tcall, req->rcall, req->err);
559 req->cb = NULL;
560 } else
561 kfree(req->rcall);
562
563 v9fs_mux_put_tag(m, tag);
564
565 wake_up(&m->equeue);
566 kfree(req);
567 }
568
569 /**
570 * v9fs_read_work - called when there is some data to be read from a transport
571 */
572 static void v9fs_read_work(void *a)
573 {
574 int n, err;
575 struct v9fs_mux_data *m;
576 struct v9fs_req *req, *rptr, *rreq;
577 struct v9fs_fcall *rcall;
578 char *rbuf;
579
580 m = a;
581
582 if (m->err < 0)
583 return;
584
585 rcall = NULL;
586 dprintk(DEBUG_MUX, "start mux %p pos %d\n", m, m->rpos);
587
588 if (!m->rcall) {
589 m->rcall =
590 kmalloc(sizeof(struct v9fs_fcall) + m->msize, GFP_KERNEL);
591 if (!m->rcall) {
592 err = -ENOMEM;
593 goto error;
594 }
595
596 m->rbuf = (char *)m->rcall + sizeof(struct v9fs_fcall);
597 m->rpos = 0;
598 }
599
600 clear_bit(Rpending, &m->wsched);
601 err = m->trans->read(m->trans, m->rbuf + m->rpos, m->msize - m->rpos);
602 dprintk(DEBUG_MUX, "mux %p got %d bytes\n", m, err);
603 if (err == -EAGAIN) {
604 clear_bit(Rworksched, &m->wsched);
605 return;
606 }
607
608 if (err <= 0)
609 goto error;
610
611 m->rpos += err;
612 while (m->rpos > 4) {
613 n = le32_to_cpu(*(__le32 *) m->rbuf);
614 if (n >= m->msize) {
615 dprintk(DEBUG_ERROR,
616 "requested packet size too big: %d\n", n);
617 err = -EIO;
618 goto error;
619 }
620
621 if (m->rpos < n)
622 break;
623
624 dump_data(m->rbuf, n);
625 err =
626 v9fs_deserialize_fcall(m->rbuf, n, m->rcall, *m->extended);
627 if (err < 0) {
628 goto error;
629 }
630
631 rcall = m->rcall;
632 rbuf = m->rbuf;
633 if (m->rpos > n) {
634 m->rcall = kmalloc(sizeof(struct v9fs_fcall) + m->msize,
635 GFP_KERNEL);
636 if (!m->rcall) {
637 err = -ENOMEM;
638 goto error;
639 }
640
641 m->rbuf = (char *)m->rcall + sizeof(struct v9fs_fcall);
642 memmove(m->rbuf, rbuf + n, m->rpos - n);
643 m->rpos -= n;
644 } else {
645 m->rcall = NULL;
646 m->rbuf = NULL;
647 m->rpos = 0;
648 }
649
650 dprintk(DEBUG_MUX, "mux %p fcall id %d tag %d\n", m, rcall->id,
651 rcall->tag);
652
653 req = NULL;
654 spin_lock(&m->lock);
655 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
656 if (rreq->tag == rcall->tag) {
657 req = rreq;
658 req->rcall = rcall;
659 list_del(&req->req_list);
660 spin_unlock(&m->lock);
661 process_request(m, req);
662 break;
663 }
664
665 }
666
667 if (!req) {
668 spin_unlock(&m->lock);
669 if (err >= 0 && rcall->id != RFLUSH)
670 dprintk(DEBUG_ERROR,
671 "unexpected response mux %p id %d tag %d\n",
672 m, rcall->id, rcall->tag);
673 kfree(rcall);
674 }
675 }
676
677 if (!list_empty(&m->req_list)) {
678 if (test_and_clear_bit(Rpending, &m->wsched))
679 n = POLLIN;
680 else
681 n = m->trans->poll(m->trans, NULL);
682
683 if (n & POLLIN) {
684 dprintk(DEBUG_MUX, "schedule read work mux %p\n", m);
685 queue_work(v9fs_mux_wq, &m->rq);
686 } else
687 clear_bit(Rworksched, &m->wsched);
688 } else
689 clear_bit(Rworksched, &m->wsched);
690
691 return;
692
693 error:
694 v9fs_mux_cancel(m, err);
695 clear_bit(Rworksched, &m->wsched);
696 }
697
698 /**
699 * v9fs_send_request - send 9P request
700 * The function can sleep until the request is scheduled for sending.
701 * The function can be interrupted. Return from the function is not
702 * a guarantee that the request is sent succesfully. Can return errors
703 * that can be retrieved by PTR_ERR macros.
704 *
705 * @m: mux data
706 * @tc: request to be sent
707 * @cb: callback function to call when response is received
708 * @cba: parameter to pass to the callback function
709 */
710 static struct v9fs_req *v9fs_send_request(struct v9fs_mux_data *m,
711 struct v9fs_fcall *tc,
712 v9fs_mux_req_callback cb, void *cba)
713 {
714 int n;
715 struct v9fs_req *req;
716
717 dprintk(DEBUG_MUX, "mux %p task %p tcall %p id %d\n", m, current,
718 tc, tc->id);
719 if (m->err < 0)
720 return ERR_PTR(m->err);
721
722 req = kmalloc(sizeof(struct v9fs_req), GFP_KERNEL);
723 if (!req)
724 return ERR_PTR(-ENOMEM);
725
726 if (tc->id == TVERSION)
727 n = V9FS_NOTAG;
728 else
729 n = v9fs_mux_get_tag(m);
730
731 if (n < 0)
732 return ERR_PTR(-ENOMEM);
733
734 v9fs_set_tag(tc, n);
735
736 req->tag = n;
737 req->tcall = tc;
738 req->rcall = NULL;
739 req->err = 0;
740 req->cb = cb;
741 req->cba = cba;
742
743 spin_lock(&m->lock);
744 list_add_tail(&req->req_list, &m->unsent_req_list);
745 spin_unlock(&m->lock);
746
747 if (test_and_clear_bit(Wpending, &m->wsched))
748 n = POLLOUT;
749 else
750 n = m->trans->poll(m->trans, NULL);
751
752 if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
753 queue_work(v9fs_mux_wq, &m->wq);
754
755 return req;
756 }
757
758 static inline void
759 v9fs_mux_flush_cb(void *a, struct v9fs_fcall *tc, struct v9fs_fcall *rc,
760 int err)
761 {
762 v9fs_mux_req_callback cb;
763 int tag;
764 struct v9fs_mux_data *m;
765 struct v9fs_req *req, *rptr;
766
767 m = a;
768 dprintk(DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m, tc,
769 rc, err, tc->params.tflush.oldtag);
770
771 spin_lock(&m->lock);
772 cb = NULL;
773 tag = tc->params.tflush.oldtag;
774 list_for_each_entry_safe(req, rptr, &m->req_list, req_list) {
775 if (req->tag == tag) {
776 list_del(&req->req_list);
777 if (req->cb) {
778 cb = req->cb;
779 req->cb = NULL;
780 spin_unlock(&m->lock);
781 (*cb) (req->cba, req->tcall, req->rcall,
782 req->err);
783 }
784 kfree(req);
785 wake_up(&m->equeue);
786 break;
787 }
788 }
789
790 if (!cb)
791 spin_unlock(&m->lock);
792
793 v9fs_mux_put_tag(m, tag);
794 kfree(tc);
795 kfree(rc);
796 }
797
798 static void
799 v9fs_mux_flush_request(struct v9fs_mux_data *m, struct v9fs_req *req)
800 {
801 struct v9fs_fcall *fc;
802
803 dprintk(DEBUG_MUX, "mux %p req %p tag %d\n", m, req, req->tag);
804
805 fc = v9fs_create_tflush(req->tag);
806 v9fs_send_request(m, fc, v9fs_mux_flush_cb, m);
807 }
808
809 static void
810 v9fs_mux_rpc_cb(void *a, struct v9fs_fcall *tc, struct v9fs_fcall *rc, int err)
811 {
812 struct v9fs_mux_rpc *r;
813
814 if (err == ERREQFLUSH) {
815 dprintk(DEBUG_MUX, "err req flush\n");
816 return;
817 }
818
819 r = a;
820 dprintk(DEBUG_MUX, "mux %p req %p tc %p rc %p err %d\n", r->m, r->req,
821 tc, rc, err);
822 r->rcall = rc;
823 r->err = err;
824 wake_up(&r->wqueue);
825 }
826
827 /**
828 * v9fs_mux_rpc - sends 9P request and waits until a response is available.
829 * The function can be interrupted.
830 * @m: mux data
831 * @tc: request to be sent
832 * @rc: pointer where a pointer to the response is stored
833 */
834 int
835 v9fs_mux_rpc(struct v9fs_mux_data *m, struct v9fs_fcall *tc,
836 struct v9fs_fcall **rc)
837 {
838 int err;
839 unsigned long flags;
840 struct v9fs_req *req;
841 struct v9fs_mux_rpc r;
842
843 r.err = 0;
844 r.rcall = NULL;
845 r.m = m;
846 init_waitqueue_head(&r.wqueue);
847
848 if (rc)
849 *rc = NULL;
850
851 req = v9fs_send_request(m, tc, v9fs_mux_rpc_cb, &r);
852 if (IS_ERR(req)) {
853 err = PTR_ERR(req);
854 dprintk(DEBUG_MUX, "error %d\n", err);
855 return PTR_ERR(req);
856 }
857
858 r.req = req;
859 dprintk(DEBUG_MUX, "mux %p tc %p tag %d rpc %p req %p\n", m, tc,
860 req->tag, &r, req);
861 err = wait_event_interruptible(r.wqueue, r.rcall != NULL || r.err < 0);
862 if (r.err < 0)
863 err = r.err;
864
865 if (err == -ERESTARTSYS && m->trans->status == Connected && m->err == 0) {
866 spin_lock(&m->lock);
867 req->tcall = NULL;
868 req->err = ERREQFLUSH;
869 spin_unlock(&m->lock);
870
871 clear_thread_flag(TIF_SIGPENDING);
872 v9fs_mux_flush_request(m, req);
873 spin_lock_irqsave(&current->sighand->siglock, flags);
874 recalc_sigpending();
875 spin_unlock_irqrestore(&current->sighand->siglock, flags);
876 }
877
878 if (!err) {
879 if (r.rcall)
880 dprintk(DEBUG_MUX, "got response id %d tag %d\n",
881 r.rcall->id, r.rcall->tag);
882
883 if (rc)
884 *rc = r.rcall;
885 else
886 kfree(r.rcall);
887 } else {
888 kfree(r.rcall);
889 dprintk(DEBUG_MUX, "got error %d\n", err);
890 if (err > 0)
891 err = -EIO;
892 }
893
894 return err;
895 }
896
897 /**
898 * v9fs_mux_rpcnb - sends 9P request without waiting for response.
899 * @m: mux data
900 * @tc: request to be sent
901 * @cb: callback function to be called when response arrives
902 * @cba: value to pass to the callback function
903 */
904 int v9fs_mux_rpcnb(struct v9fs_mux_data *m, struct v9fs_fcall *tc,
905 v9fs_mux_req_callback cb, void *a)
906 {
907 int err;
908 struct v9fs_req *req;
909
910 req = v9fs_send_request(m, tc, cb, a);
911 if (IS_ERR(req)) {
912 err = PTR_ERR(req);
913 dprintk(DEBUG_MUX, "error %d\n", err);
914 return PTR_ERR(req);
915 }
916
917 dprintk(DEBUG_MUX, "mux %p tc %p tag %d\n", m, tc, req->tag);
918 return 0;
919 }
920
921 /**
922 * v9fs_mux_cancel - cancel all pending requests with error
923 * @m: mux data
924 * @err: error code
925 */
926 void v9fs_mux_cancel(struct v9fs_mux_data *m, int err)
927 {
928 struct v9fs_req *req, *rtmp;
929 LIST_HEAD(cancel_list);
930
931 dprintk(DEBUG_MUX, "mux %p err %d\n", m, err);
932 m->err = err;
933 spin_lock(&m->lock);
934 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
935 list_move(&req->req_list, &cancel_list);
936 }
937 spin_unlock(&m->lock);
938
939 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
940 list_del(&req->req_list);
941 if (!req->err)
942 req->err = err;
943
944 if (req->cb)
945 (*req->cb) (req->cba, req->tcall, req->rcall, req->err);
946 else
947 kfree(req->rcall);
948
949 kfree(req);
950 }
951
952 wake_up(&m->equeue);
953 }
954
955 static u16 v9fs_mux_get_tag(struct v9fs_mux_data *m)
956 {
957 int tag;
958
959 tag = v9fs_get_idpool(&m->tidpool);
960 if (tag < 0)
961 return V9FS_NOTAG;
962 else
963 return (u16) tag;
964 }
965
966 static void v9fs_mux_put_tag(struct v9fs_mux_data *m, u16 tag)
967 {
968 if (tag != V9FS_NOTAG && v9fs_check_idpool(tag, &m->tidpool))
969 v9fs_put_idpool(tag, &m->tidpool);
970 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree