[PATCH] briq_panel: read() and write() get __user pointers, damnit
[linux-2.6/verdex.git] / fs / 9p / mux.c
blob90a79c784549f108f4929a7865295deaf0a69b23
1 /*
2 * linux/fs/9p/mux.c
4 * Protocol Multiplexer
6 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
7 * Copyright (C) 2004-2005 by Latchesar Ionkov <lucho@ionkov.net>
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.
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.
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
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>
34 #include "debug.h"
35 #include "v9fs.h"
36 #include "9p.h"
37 #include "conv.h"
38 #include "transport.h"
39 #include "mux.h"
41 #define ERREQFLUSH 1
42 #define SCHED_TIMEOUT 10
43 #define MAXPOLLWADDR 2
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 */
52 enum {
53 None,
54 Flushing,
55 Flushed,
58 struct v9fs_mux_poll_task;
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;
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;
98 struct v9fs_mux_poll_task {
99 struct task_struct *task;
100 struct list_head mux_list;
101 int muxnum;
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;
112 static int v9fs_poll_proc(void *);
113 static void v9fs_read_work(void *);
114 static void v9fs_write_work(void *);
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);
120 static DEFINE_MUTEX(v9fs_mux_task_lock);
121 static struct workqueue_struct *v9fs_mux_wq;
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];
127 int v9fs_mux_global_init(void)
129 int i;
131 for (i = 0; i < ARRAY_SIZE(v9fs_mux_poll_tasks); i++)
132 v9fs_mux_poll_tasks[i].task = NULL;
134 v9fs_mux_wq = create_workqueue("v9fs");
135 if (!v9fs_mux_wq)
136 return -ENOMEM;
138 return 0;
141 void v9fs_mux_global_exit(void)
143 destroy_workqueue(v9fs_mux_wq);
147 * v9fs_mux_calc_poll_procs - calculates the number of polling procs
148 * based on the number of mounted v9fs filesystems.
150 * The current implementation returns sqrt of the number of mounts.
152 static int v9fs_mux_calc_poll_procs(int muxnum)
154 int n;
156 if (v9fs_mux_poll_task_num)
157 n = muxnum / v9fs_mux_poll_task_num +
158 (muxnum % v9fs_mux_poll_task_num ? 1 : 0);
159 else
160 n = 1;
162 if (n > ARRAY_SIZE(v9fs_mux_poll_tasks))
163 n = ARRAY_SIZE(v9fs_mux_poll_tasks);
165 return n;
168 static int v9fs_mux_poll_start(struct v9fs_mux_data *m)
170 int i, n;
171 struct v9fs_mux_poll_task *vpt, *vptlast;
172 struct task_struct *pproc;
174 dprintk(DEBUG_MUX, "mux %p muxnum %d procnum %d\n", m, v9fs_mux_num,
175 v9fs_mux_poll_task_num);
176 mutex_lock(&v9fs_mux_task_lock);
178 n = v9fs_mux_calc_poll_procs(v9fs_mux_num + 1);
179 if (n > v9fs_mux_poll_task_num) {
180 for (i = 0; i < ARRAY_SIZE(v9fs_mux_poll_tasks); i++) {
181 if (v9fs_mux_poll_tasks[i].task == NULL) {
182 vpt = &v9fs_mux_poll_tasks[i];
183 dprintk(DEBUG_MUX, "create proc %p\n", vpt);
184 pproc = kthread_create(v9fs_poll_proc, vpt,
185 "v9fs-poll");
187 if (!IS_ERR(pproc)) {
188 vpt->task = pproc;
189 INIT_LIST_HEAD(&vpt->mux_list);
190 vpt->muxnum = 0;
191 v9fs_mux_poll_task_num++;
192 wake_up_process(vpt->task);
194 break;
198 if (i >= ARRAY_SIZE(v9fs_mux_poll_tasks))
199 dprintk(DEBUG_ERROR, "warning: no free poll slots\n");
202 n = (v9fs_mux_num + 1) / v9fs_mux_poll_task_num +
203 ((v9fs_mux_num + 1) % v9fs_mux_poll_task_num ? 1 : 0);
205 vptlast = NULL;
206 for (i = 0; i < ARRAY_SIZE(v9fs_mux_poll_tasks); i++) {
207 vpt = &v9fs_mux_poll_tasks[i];
208 if (vpt->task != NULL) {
209 vptlast = vpt;
210 if (vpt->muxnum < n) {
211 dprintk(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, sizeof(m->poll_waddr));
216 init_poll_funcptr(&m->pt, v9fs_pollwait);
217 break;
222 if (i >= ARRAY_SIZE(v9fs_mux_poll_tasks)) {
223 if (vptlast == NULL)
224 return -ENOMEM;
226 dprintk(DEBUG_MUX, "put in proc %d\n", i);
227 list_add(&m->mux_list, &vptlast->mux_list);
228 vptlast->muxnum++;
229 m->poll_task = vptlast;
230 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
231 init_poll_funcptr(&m->pt, v9fs_pollwait);
234 v9fs_mux_num++;
235 mutex_unlock(&v9fs_mux_task_lock);
237 return 0;
240 static void v9fs_mux_poll_stop(struct v9fs_mux_data *m)
242 int i;
243 struct v9fs_mux_poll_task *vpt;
245 mutex_lock(&v9fs_mux_task_lock);
246 vpt = m->poll_task;
247 list_del(&m->mux_list);
248 for(i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
249 if (m->poll_waddr[i] != NULL) {
250 remove_wait_queue(m->poll_waddr[i], &m->poll_wait[i]);
251 m->poll_waddr[i] = NULL;
254 vpt->muxnum--;
255 if (!vpt->muxnum) {
256 dprintk(DEBUG_MUX, "destroy proc %p\n", vpt);
257 send_sig(SIGKILL, vpt->task, 1);
258 vpt->task = NULL;
259 v9fs_mux_poll_task_num--;
261 v9fs_mux_num--;
262 mutex_unlock(&v9fs_mux_task_lock);
266 * v9fs_mux_init - allocate and initialize the per-session mux data
267 * Creates the polling task if this is the first session.
269 * @trans - transport structure
270 * @msize - maximum message size
271 * @extended - pointer to the extended flag
273 struct v9fs_mux_data *v9fs_mux_init(struct v9fs_transport *trans, int msize,
274 unsigned char *extended)
276 int i, n;
277 struct v9fs_mux_data *m, *mtmp;
279 dprintk(DEBUG_MUX, "transport %p msize %d\n", trans, msize);
280 m = kmalloc(sizeof(struct v9fs_mux_data), GFP_KERNEL);
281 if (!m)
282 return ERR_PTR(-ENOMEM);
284 spin_lock_init(&m->lock);
285 INIT_LIST_HEAD(&m->mux_list);
286 m->msize = msize;
287 m->extended = extended;
288 m->trans = trans;
289 idr_init(&m->tagpool.pool);
290 init_MUTEX(&m->tagpool.lock);
291 m->err = 0;
292 init_waitqueue_head(&m->equeue);
293 INIT_LIST_HEAD(&m->req_list);
294 INIT_LIST_HEAD(&m->unsent_req_list);
295 m->rcall = NULL;
296 m->rpos = 0;
297 m->rbuf = NULL;
298 m->wpos = m->wsize = 0;
299 m->wbuf = NULL;
300 INIT_WORK(&m->rq, v9fs_read_work, m);
301 INIT_WORK(&m->wq, v9fs_write_work, m);
302 m->wsched = 0;
303 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
304 m->poll_task = NULL;
305 n = v9fs_mux_poll_start(m);
306 if (n)
307 return ERR_PTR(n);
309 n = trans->poll(trans, &m->pt);
310 if (n & POLLIN) {
311 dprintk(DEBUG_MUX, "mux %p can read\n", m);
312 set_bit(Rpending, &m->wsched);
315 if (n & POLLOUT) {
316 dprintk(DEBUG_MUX, "mux %p can write\n", m);
317 set_bit(Wpending, &m->wsched);
320 for(i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
321 if (IS_ERR(m->poll_waddr[i])) {
322 v9fs_mux_poll_stop(m);
323 mtmp = (void *)m->poll_waddr; /* the error code */
324 kfree(m);
325 m = mtmp;
326 break;
330 return m;
334 * v9fs_mux_destroy - cancels all pending requests and frees mux resources
336 void v9fs_mux_destroy(struct v9fs_mux_data *m)
338 dprintk(DEBUG_MUX, "mux %p prev %p next %p\n", m,
339 m->mux_list.prev, m->mux_list.next);
340 v9fs_mux_cancel(m, -ECONNRESET);
342 if (!list_empty(&m->req_list)) {
343 /* wait until all processes waiting on this session exit */
344 dprintk(DEBUG_MUX, "mux %p waiting for empty request queue\n",
346 wait_event_timeout(m->equeue, (list_empty(&m->req_list)), 5000);
347 dprintk(DEBUG_MUX, "mux %p request queue empty: %d\n", m,
348 list_empty(&m->req_list));
351 v9fs_mux_poll_stop(m);
352 m->trans = NULL;
354 kfree(m);
358 * v9fs_pollwait - called by files poll operation to add v9fs-poll task
359 * to files wait queue
361 static void
362 v9fs_pollwait(struct file *filp, wait_queue_head_t * wait_address,
363 poll_table * p)
365 int i;
366 struct v9fs_mux_data *m;
368 m = container_of(p, struct v9fs_mux_data, pt);
369 for(i = 0; i < ARRAY_SIZE(m->poll_waddr); i++)
370 if (m->poll_waddr[i] == NULL)
371 break;
373 if (i >= ARRAY_SIZE(m->poll_waddr)) {
374 dprintk(DEBUG_ERROR, "not enough wait_address slots\n");
375 return;
378 m->poll_waddr[i] = wait_address;
380 if (!wait_address) {
381 dprintk(DEBUG_ERROR, "no wait_address\n");
382 m->poll_waddr[i] = ERR_PTR(-EIO);
383 return;
386 init_waitqueue_entry(&m->poll_wait[i], m->poll_task->task);
387 add_wait_queue(wait_address, &m->poll_wait[i]);
391 * v9fs_poll_mux - polls a mux and schedules read or write works if necessary
393 static void v9fs_poll_mux(struct v9fs_mux_data *m)
395 int n;
397 if (m->err < 0)
398 return;
400 n = m->trans->poll(m->trans, NULL);
401 if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) {
402 dprintk(DEBUG_MUX, "error mux %p err %d\n", m, n);
403 if (n >= 0)
404 n = -ECONNRESET;
405 v9fs_mux_cancel(m, n);
408 if (n & POLLIN) {
409 set_bit(Rpending, &m->wsched);
410 dprintk(DEBUG_MUX, "mux %p can read\n", m);
411 if (!test_and_set_bit(Rworksched, &m->wsched)) {
412 dprintk(DEBUG_MUX, "schedule read work mux %p\n", m);
413 queue_work(v9fs_mux_wq, &m->rq);
417 if (n & POLLOUT) {
418 set_bit(Wpending, &m->wsched);
419 dprintk(DEBUG_MUX, "mux %p can write\n", m);
420 if ((m->wsize || !list_empty(&m->unsent_req_list))
421 && !test_and_set_bit(Wworksched, &m->wsched)) {
422 dprintk(DEBUG_MUX, "schedule write work mux %p\n", m);
423 queue_work(v9fs_mux_wq, &m->wq);
429 * v9fs_poll_proc - polls all v9fs transports for new events and queues
430 * the appropriate work to the work queue
432 static int v9fs_poll_proc(void *a)
434 struct v9fs_mux_data *m, *mtmp;
435 struct v9fs_mux_poll_task *vpt;
437 vpt = a;
438 dprintk(DEBUG_MUX, "start %p %p\n", current, vpt);
439 allow_signal(SIGKILL);
440 while (!kthread_should_stop()) {
441 set_current_state(TASK_INTERRUPTIBLE);
442 if (signal_pending(current))
443 break;
445 list_for_each_entry_safe(m, mtmp, &vpt->mux_list, mux_list) {
446 v9fs_poll_mux(m);
449 dprintk(DEBUG_MUX, "sleeping...\n");
450 schedule_timeout(SCHED_TIMEOUT * HZ);
453 __set_current_state(TASK_RUNNING);
454 dprintk(DEBUG_MUX, "finish\n");
455 return 0;
459 * v9fs_write_work - called when a transport can send some data
461 static void v9fs_write_work(void *a)
463 int n, err;
464 struct v9fs_mux_data *m;
465 struct v9fs_req *req;
467 m = a;
469 if (m->err < 0) {
470 clear_bit(Wworksched, &m->wsched);
471 return;
474 if (!m->wsize) {
475 if (list_empty(&m->unsent_req_list)) {
476 clear_bit(Wworksched, &m->wsched);
477 return;
480 spin_lock(&m->lock);
481 again:
482 req = list_entry(m->unsent_req_list.next, struct v9fs_req,
483 req_list);
484 list_move_tail(&req->req_list, &m->req_list);
485 if (req->err == ERREQFLUSH)
486 goto again;
488 m->wbuf = req->tcall->sdata;
489 m->wsize = req->tcall->size;
490 m->wpos = 0;
491 dump_data(m->wbuf, m->wsize);
492 spin_unlock(&m->lock);
495 dprintk(DEBUG_MUX, "mux %p pos %d size %d\n", m, m->wpos, m->wsize);
496 clear_bit(Wpending, &m->wsched);
497 err = m->trans->write(m->trans, m->wbuf + m->wpos, m->wsize - m->wpos);
498 dprintk(DEBUG_MUX, "mux %p sent %d bytes\n", m, err);
499 if (err == -EAGAIN) {
500 clear_bit(Wworksched, &m->wsched);
501 return;
504 if (err <= 0)
505 goto error;
507 m->wpos += err;
508 if (m->wpos == m->wsize)
509 m->wpos = m->wsize = 0;
511 if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
512 if (test_and_clear_bit(Wpending, &m->wsched))
513 n = POLLOUT;
514 else
515 n = m->trans->poll(m->trans, NULL);
517 if (n & POLLOUT) {
518 dprintk(DEBUG_MUX, "schedule write work mux %p\n", m);
519 queue_work(v9fs_mux_wq, &m->wq);
520 } else
521 clear_bit(Wworksched, &m->wsched);
522 } else
523 clear_bit(Wworksched, &m->wsched);
525 return;
527 error:
528 v9fs_mux_cancel(m, err);
529 clear_bit(Wworksched, &m->wsched);
532 static void process_request(struct v9fs_mux_data *m, struct v9fs_req *req)
534 int ecode;
535 struct v9fs_str *ename;
537 if (!req->err && req->rcall->id == RERROR) {
538 ecode = req->rcall->params.rerror.errno;
539 ename = &req->rcall->params.rerror.error;
541 dprintk(DEBUG_MUX, "Rerror %.*s\n", ename->len, ename->str);
543 if (*m->extended)
544 req->err = -ecode;
546 if (!req->err) {
547 req->err = v9fs_errstr2errno(ename->str, ename->len);
549 if (!req->err) { /* string match failed */
550 PRINT_FCALL_ERROR("unknown error", req->rcall);
553 if (!req->err)
554 req->err = -ESERVERFAULT;
556 } else if (req->tcall && req->rcall->id != req->tcall->id + 1) {
557 dprintk(DEBUG_ERROR, "fcall mismatch: expected %d, got %d\n",
558 req->tcall->id + 1, req->rcall->id);
559 if (!req->err)
560 req->err = -EIO;
565 * v9fs_read_work - called when there is some data to be read from a transport
567 static void v9fs_read_work(void *a)
569 int n, err;
570 struct v9fs_mux_data *m;
571 struct v9fs_req *req, *rptr, *rreq;
572 struct v9fs_fcall *rcall;
573 char *rbuf;
575 m = a;
577 if (m->err < 0)
578 return;
580 rcall = NULL;
581 dprintk(DEBUG_MUX, "start mux %p pos %d\n", m, m->rpos);
583 if (!m->rcall) {
584 m->rcall =
585 kmalloc(sizeof(struct v9fs_fcall) + m->msize, GFP_KERNEL);
586 if (!m->rcall) {
587 err = -ENOMEM;
588 goto error;
591 m->rbuf = (char *)m->rcall + sizeof(struct v9fs_fcall);
592 m->rpos = 0;
595 clear_bit(Rpending, &m->wsched);
596 err = m->trans->read(m->trans, m->rbuf + m->rpos, m->msize - m->rpos);
597 dprintk(DEBUG_MUX, "mux %p got %d bytes\n", m, err);
598 if (err == -EAGAIN) {
599 clear_bit(Rworksched, &m->wsched);
600 return;
603 if (err <= 0)
604 goto error;
606 m->rpos += err;
607 while (m->rpos > 4) {
608 n = le32_to_cpu(*(__le32 *) m->rbuf);
609 if (n >= m->msize) {
610 dprintk(DEBUG_ERROR,
611 "requested packet size too big: %d\n", n);
612 err = -EIO;
613 goto error;
616 if (m->rpos < n)
617 break;
619 dump_data(m->rbuf, n);
620 err =
621 v9fs_deserialize_fcall(m->rbuf, n, m->rcall, *m->extended);
622 if (err < 0) {
623 goto error;
626 if ((v9fs_debug_level&DEBUG_FCALL) == DEBUG_FCALL) {
627 char buf[150];
629 v9fs_printfcall(buf, sizeof(buf), m->rcall,
630 *m->extended);
631 printk(KERN_NOTICE ">>> %p %s\n", m, buf);
634 rcall = m->rcall;
635 rbuf = m->rbuf;
636 if (m->rpos > n) {
637 m->rcall = kmalloc(sizeof(struct v9fs_fcall) + m->msize,
638 GFP_KERNEL);
639 if (!m->rcall) {
640 err = -ENOMEM;
641 goto error;
644 m->rbuf = (char *)m->rcall + sizeof(struct v9fs_fcall);
645 memmove(m->rbuf, rbuf + n, m->rpos - n);
646 m->rpos -= n;
647 } else {
648 m->rcall = NULL;
649 m->rbuf = NULL;
650 m->rpos = 0;
653 dprintk(DEBUG_MUX, "mux %p fcall id %d tag %d\n", m, rcall->id,
654 rcall->tag);
656 req = NULL;
657 spin_lock(&m->lock);
658 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
659 if (rreq->tag == rcall->tag) {
660 req = rreq;
661 if (req->flush != Flushing)
662 list_del(&req->req_list);
663 break;
666 spin_unlock(&m->lock);
668 if (req) {
669 req->rcall = rcall;
670 process_request(m, req);
672 if (req->flush != Flushing) {
673 if (req->cb)
674 (*req->cb) (req, req->cba);
675 else
676 kfree(req->rcall);
678 wake_up(&m->equeue);
680 } else {
681 if (err >= 0 && rcall->id != RFLUSH)
682 dprintk(DEBUG_ERROR,
683 "unexpected response mux %p id %d tag %d\n",
684 m, rcall->id, rcall->tag);
685 kfree(rcall);
689 if (!list_empty(&m->req_list)) {
690 if (test_and_clear_bit(Rpending, &m->wsched))
691 n = POLLIN;
692 else
693 n = m->trans->poll(m->trans, NULL);
695 if (n & POLLIN) {
696 dprintk(DEBUG_MUX, "schedule read work mux %p\n", m);
697 queue_work(v9fs_mux_wq, &m->rq);
698 } else
699 clear_bit(Rworksched, &m->wsched);
700 } else
701 clear_bit(Rworksched, &m->wsched);
703 return;
705 error:
706 v9fs_mux_cancel(m, err);
707 clear_bit(Rworksched, &m->wsched);
711 * v9fs_send_request - send 9P request
712 * The function can sleep until the request is scheduled for sending.
713 * The function can be interrupted. Return from the function is not
714 * a guarantee that the request is sent successfully. Can return errors
715 * that can be retrieved by PTR_ERR macros.
717 * @m: mux data
718 * @tc: request to be sent
719 * @cb: callback function to call when response is received
720 * @cba: parameter to pass to the callback function
722 static struct v9fs_req *v9fs_send_request(struct v9fs_mux_data *m,
723 struct v9fs_fcall *tc,
724 v9fs_mux_req_callback cb, void *cba)
726 int n;
727 struct v9fs_req *req;
729 dprintk(DEBUG_MUX, "mux %p task %p tcall %p id %d\n", m, current,
730 tc, tc->id);
731 if (m->err < 0)
732 return ERR_PTR(m->err);
734 req = kmalloc(sizeof(struct v9fs_req), GFP_KERNEL);
735 if (!req)
736 return ERR_PTR(-ENOMEM);
738 if (tc->id == TVERSION)
739 n = V9FS_NOTAG;
740 else
741 n = v9fs_mux_get_tag(m);
743 if (n < 0)
744 return ERR_PTR(-ENOMEM);
746 v9fs_set_tag(tc, n);
747 if ((v9fs_debug_level&DEBUG_FCALL) == DEBUG_FCALL) {
748 char buf[150];
750 v9fs_printfcall(buf, sizeof(buf), tc, *m->extended);
751 printk(KERN_NOTICE "<<< %p %s\n", m, buf);
754 spin_lock_init(&req->lock);
755 req->tag = n;
756 req->tcall = tc;
757 req->rcall = NULL;
758 req->err = 0;
759 req->cb = cb;
760 req->cba = cba;
761 req->flush = None;
763 spin_lock(&m->lock);
764 list_add_tail(&req->req_list, &m->unsent_req_list);
765 spin_unlock(&m->lock);
767 if (test_and_clear_bit(Wpending, &m->wsched))
768 n = POLLOUT;
769 else
770 n = m->trans->poll(m->trans, NULL);
772 if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
773 queue_work(v9fs_mux_wq, &m->wq);
775 return req;
778 static void v9fs_mux_free_request(struct v9fs_mux_data *m, struct v9fs_req *req)
780 v9fs_mux_put_tag(m, req->tag);
781 kfree(req);
784 static void v9fs_mux_flush_cb(struct v9fs_req *freq, void *a)
786 v9fs_mux_req_callback cb;
787 int tag;
788 struct v9fs_mux_data *m;
789 struct v9fs_req *req, *rreq, *rptr;
791 m = a;
792 dprintk(DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
793 freq->tcall, freq->rcall, freq->err,
794 freq->tcall->params.tflush.oldtag);
796 spin_lock(&m->lock);
797 cb = NULL;
798 tag = freq->tcall->params.tflush.oldtag;
799 req = NULL;
800 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
801 if (rreq->tag == tag) {
802 req = rreq;
803 list_del(&req->req_list);
804 break;
807 spin_unlock(&m->lock);
809 if (req) {
810 spin_lock(&req->lock);
811 req->flush = Flushed;
812 spin_unlock(&req->lock);
814 if (req->cb)
815 (*req->cb) (req, req->cba);
816 else
817 kfree(req->rcall);
819 wake_up(&m->equeue);
822 kfree(freq->tcall);
823 kfree(freq->rcall);
824 v9fs_mux_free_request(m, freq);
827 static int
828 v9fs_mux_flush_request(struct v9fs_mux_data *m, struct v9fs_req *req)
830 struct v9fs_fcall *fc;
831 struct v9fs_req *rreq, *rptr;
833 dprintk(DEBUG_MUX, "mux %p req %p tag %d\n", m, req, req->tag);
835 /* if a response was received for a request, do nothing */
836 spin_lock(&req->lock);
837 if (req->rcall || req->err) {
838 spin_unlock(&req->lock);
839 dprintk(DEBUG_MUX, "mux %p req %p response already received\n", m, req);
840 return 0;
843 req->flush = Flushing;
844 spin_unlock(&req->lock);
846 spin_lock(&m->lock);
847 /* if the request is not sent yet, just remove it from the list */
848 list_for_each_entry_safe(rreq, rptr, &m->unsent_req_list, req_list) {
849 if (rreq->tag == req->tag) {
850 dprintk(DEBUG_MUX, "mux %p req %p request is not sent yet\n", m, req);
851 list_del(&rreq->req_list);
852 req->flush = Flushed;
853 spin_unlock(&m->lock);
854 if (req->cb)
855 (*req->cb) (req, req->cba);
856 return 0;
859 spin_unlock(&m->lock);
861 clear_thread_flag(TIF_SIGPENDING);
862 fc = v9fs_create_tflush(req->tag);
863 v9fs_send_request(m, fc, v9fs_mux_flush_cb, m);
864 return 1;
867 static void
868 v9fs_mux_rpc_cb(struct v9fs_req *req, void *a)
870 struct v9fs_mux_rpc *r;
872 dprintk(DEBUG_MUX, "req %p r %p\n", req, a);
873 r = a;
874 r->rcall = req->rcall;
875 r->err = req->err;
877 if (req->flush!=None && !req->err)
878 r->err = -ERESTARTSYS;
880 wake_up(&r->wqueue);
884 * v9fs_mux_rpc - sends 9P request and waits until a response is available.
885 * The function can be interrupted.
886 * @m: mux data
887 * @tc: request to be sent
888 * @rc: pointer where a pointer to the response is stored
891 v9fs_mux_rpc(struct v9fs_mux_data *m, struct v9fs_fcall *tc,
892 struct v9fs_fcall **rc)
894 int err, sigpending;
895 unsigned long flags;
896 struct v9fs_req *req;
897 struct v9fs_mux_rpc r;
899 r.err = 0;
900 r.tcall = tc;
901 r.rcall = NULL;
902 r.m = m;
903 init_waitqueue_head(&r.wqueue);
905 if (rc)
906 *rc = NULL;
908 sigpending = 0;
909 if (signal_pending(current)) {
910 sigpending = 1;
911 clear_thread_flag(TIF_SIGPENDING);
914 req = v9fs_send_request(m, tc, v9fs_mux_rpc_cb, &r);
915 if (IS_ERR(req)) {
916 err = PTR_ERR(req);
917 dprintk(DEBUG_MUX, "error %d\n", err);
918 return err;
921 err = wait_event_interruptible(r.wqueue, r.rcall != NULL || r.err < 0);
922 if (r.err < 0)
923 err = r.err;
925 if (err == -ERESTARTSYS && m->trans->status == Connected && m->err == 0) {
926 if (v9fs_mux_flush_request(m, req)) {
927 /* wait until we get response of the flush message */
928 do {
929 clear_thread_flag(TIF_SIGPENDING);
930 err = wait_event_interruptible(r.wqueue,
931 r.rcall || r.err);
932 } while (!r.rcall && !r.err && err==-ERESTARTSYS &&
933 m->trans->status==Connected && !m->err);
935 err = -ERESTARTSYS;
937 sigpending = 1;
940 if (sigpending) {
941 spin_lock_irqsave(&current->sighand->siglock, flags);
942 recalc_sigpending();
943 spin_unlock_irqrestore(&current->sighand->siglock, flags);
946 if (rc)
947 *rc = r.rcall;
948 else
949 kfree(r.rcall);
951 v9fs_mux_free_request(m, req);
952 if (err > 0)
953 err = -EIO;
955 return err;
958 #if 0
960 * v9fs_mux_rpcnb - sends 9P request without waiting for response.
961 * @m: mux data
962 * @tc: request to be sent
963 * @cb: callback function to be called when response arrives
964 * @cba: value to pass to the callback function
966 int v9fs_mux_rpcnb(struct v9fs_mux_data *m, struct v9fs_fcall *tc,
967 v9fs_mux_req_callback cb, void *a)
969 int err;
970 struct v9fs_req *req;
972 req = v9fs_send_request(m, tc, cb, a);
973 if (IS_ERR(req)) {
974 err = PTR_ERR(req);
975 dprintk(DEBUG_MUX, "error %d\n", err);
976 return PTR_ERR(req);
979 dprintk(DEBUG_MUX, "mux %p tc %p tag %d\n", m, tc, req->tag);
980 return 0;
982 #endif /* 0 */
985 * v9fs_mux_cancel - cancel all pending requests with error
986 * @m: mux data
987 * @err: error code
989 void v9fs_mux_cancel(struct v9fs_mux_data *m, int err)
991 struct v9fs_req *req, *rtmp;
992 LIST_HEAD(cancel_list);
994 dprintk(DEBUG_ERROR, "mux %p err %d\n", m, err);
995 m->err = err;
996 spin_lock(&m->lock);
997 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
998 list_move(&req->req_list, &cancel_list);
1000 list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
1001 list_move(&req->req_list, &cancel_list);
1003 spin_unlock(&m->lock);
1005 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
1006 list_del(&req->req_list);
1007 if (!req->err)
1008 req->err = err;
1010 if (req->cb)
1011 (*req->cb) (req, req->cba);
1012 else
1013 kfree(req->rcall);
1016 wake_up(&m->equeue);
1019 static u16 v9fs_mux_get_tag(struct v9fs_mux_data *m)
1021 int tag;
1023 tag = v9fs_get_idpool(&m->tagpool);
1024 if (tag < 0)
1025 return V9FS_NOTAG;
1026 else
1027 return (u16) tag;
1030 static void v9fs_mux_put_tag(struct v9fs_mux_data *m, u16 tag)
1032 if (tag != V9FS_NOTAG && v9fs_check_idpool(tag, &m->tagpool))
1033 v9fs_put_idpool(tag, &m->tagpool);