?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
ACPI: thinkpad-acpi: fix regression on HKEY LID event handling
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / net / 9p / mux.c
blob5d70558c4c6124065cc3f6371473dd67ed0a9db9
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 (IS_ERR(m->tagpool)) {
292 mtmp = ERR_PTR(-ENOMEM);
293 kfree(m);
294 return mtmp;
295 }
296
297 m->err = 0;
298 init_waitqueue_head(&m->equeue);
299 INIT_LIST_HEAD(&m->req_list);
300 INIT_LIST_HEAD(&m->unsent_req_list);
301 m->rcall = NULL;
302 m->rpos = 0;
303 m->rbuf = NULL;
304 m->wpos = m->wsize = 0;
305 m->wbuf = NULL;
306 INIT_WORK(&m->rq, p9_read_work);
307 INIT_WORK(&m->wq, p9_write_work);
308 m->wsched = 0;
309 memset(&m->poll_waddr, 0, sizeof(m->poll_waddr));
310 m->poll_task = NULL;
311 n = p9_mux_poll_start(m);
312 if (n) {
313 kfree(m);
314 return ERR_PTR(n);
315 }
316
317 n = trans->poll(trans, &m->pt);
318 if (n & POLLIN) {
319 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
320 set_bit(Rpending, &m->wsched);
321 }
322
323 if (n & POLLOUT) {
324 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
325 set_bit(Wpending, &m->wsched);
326 }
327
328 for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++) {
329 if (IS_ERR(m->poll_waddr[i])) {
330 p9_mux_poll_stop(m);
331 mtmp = (void *)m->poll_waddr; /* the error code */
332 kfree(m);
333 m = mtmp;
334 break;
335 }
336 }
337
338 return m;
339 }
340 EXPORT_SYMBOL(p9_conn_create);
341
342 /**
343 * p9_mux_destroy - cancels all pending requests and frees mux resources
344 */
345 void p9_conn_destroy(struct p9_conn *m)
346 {
347 P9_DPRINTK(P9_DEBUG_MUX, "mux %p prev %p next %p\n", m,
348 m->mux_list.prev, m->mux_list.next);
349 p9_conn_cancel(m, -ECONNRESET);
350
351 if (!list_empty(&m->req_list)) {
352 /* wait until all processes waiting on this session exit */
353 P9_DPRINTK(P9_DEBUG_MUX,
354 "mux %p waiting for empty request queue\n", m);
355 wait_event_timeout(m->equeue, (list_empty(&m->req_list)), 5000);
356 P9_DPRINTK(P9_DEBUG_MUX, "mux %p request queue empty: %d\n", m,
357 list_empty(&m->req_list));
358 }
359
360 p9_mux_poll_stop(m);
361 m->trans = NULL;
362 p9_idpool_destroy(m->tagpool);
363 kfree(m);
364 }
365 EXPORT_SYMBOL(p9_conn_destroy);
366
367 /**
368 * p9_pollwait - called by files poll operation to add v9fs-poll task
369 * to files wait queue
370 */
371 static void
372 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address,
373 poll_table * p)
374 {
375 int i;
376 struct p9_conn *m;
377
378 m = container_of(p, struct p9_conn, pt);
379 for (i = 0; i < ARRAY_SIZE(m->poll_waddr); i++)
380 if (m->poll_waddr[i] == NULL)
381 break;
382
383 if (i >= ARRAY_SIZE(m->poll_waddr)) {
384 P9_DPRINTK(P9_DEBUG_ERROR, "not enough wait_address slots\n");
385 return;
386 }
387
388 m->poll_waddr[i] = wait_address;
389
390 if (!wait_address) {
391 P9_DPRINTK(P9_DEBUG_ERROR, "no wait_address\n");
392 m->poll_waddr[i] = ERR_PTR(-EIO);
393 return;
394 }
395
396 init_waitqueue_entry(&m->poll_wait[i], m->poll_task->task);
397 add_wait_queue(wait_address, &m->poll_wait[i]);
398 }
399
400 /**
401 * p9_poll_mux - polls a mux and schedules read or write works if necessary
402 */
403 static void p9_poll_mux(struct p9_conn *m)
404 {
405 int n;
406
407 if (m->err < 0)
408 return;
409
410 n = m->trans->poll(m->trans, NULL);
411 if (n < 0 || n & (POLLERR | POLLHUP | POLLNVAL)) {
412 P9_DPRINTK(P9_DEBUG_MUX, "error mux %p err %d\n", m, n);
413 if (n >= 0)
414 n = -ECONNRESET;
415 p9_conn_cancel(m, n);
416 }
417
418 if (n & POLLIN) {
419 set_bit(Rpending, &m->wsched);
420 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can read\n", m);
421 if (!test_and_set_bit(Rworksched, &m->wsched)) {
422 P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
423 queue_work(p9_mux_wq, &m->rq);
424 }
425 }
426
427 if (n & POLLOUT) {
428 set_bit(Wpending, &m->wsched);
429 P9_DPRINTK(P9_DEBUG_MUX, "mux %p can write\n", m);
430 if ((m->wsize || !list_empty(&m->unsent_req_list))
431 && !test_and_set_bit(Wworksched, &m->wsched)) {
432 P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
433 queue_work(p9_mux_wq, &m->wq);
434 }
435 }
436 }
437
438 /**
439 * p9_poll_proc - polls all v9fs transports for new events and queues
440 * the appropriate work to the work queue
441 */
442 static int p9_poll_proc(void *a)
443 {
444 struct p9_conn *m, *mtmp;
445 struct p9_mux_poll_task *vpt;
446
447 vpt = a;
448 P9_DPRINTK(P9_DEBUG_MUX, "start %p %p\n", current, vpt);
449 while (!kthread_should_stop()) {
450 set_current_state(TASK_INTERRUPTIBLE);
451
452 list_for_each_entry_safe(m, mtmp, &vpt->mux_list, mux_list) {
453 p9_poll_mux(m);
454 }
455
456 P9_DPRINTK(P9_DEBUG_MUX, "sleeping...\n");
457 schedule_timeout(SCHED_TIMEOUT * HZ);
458 }
459
460 __set_current_state(TASK_RUNNING);
461 P9_DPRINTK(P9_DEBUG_MUX, "finish\n");
462 return 0;
463 }
464
465 /**
466 * p9_write_work - called when a transport can send some data
467 */
468 static void p9_write_work(struct work_struct *work)
469 {
470 int n, err;
471 struct p9_conn *m;
472 struct p9_req *req;
473
474 m = container_of(work, struct p9_conn, wq);
475
476 if (m->err < 0) {
477 clear_bit(Wworksched, &m->wsched);
478 return;
479 }
480
481 if (!m->wsize) {
482 if (list_empty(&m->unsent_req_list)) {
483 clear_bit(Wworksched, &m->wsched);
484 return;
485 }
486
487 spin_lock(&m->lock);
488 again:
489 req = list_entry(m->unsent_req_list.next, struct p9_req,
490 req_list);
491 list_move_tail(&req->req_list, &m->req_list);
492 if (req->err == ERREQFLUSH)
493 goto again;
494
495 m->wbuf = req->tcall->sdata;
496 m->wsize = req->tcall->size;
497 m->wpos = 0;
498 spin_unlock(&m->lock);
499 }
500
501 P9_DPRINTK(P9_DEBUG_MUX, "mux %p pos %d size %d\n", m, m->wpos,
502 m->wsize);
503 clear_bit(Wpending, &m->wsched);
504 err = m->trans->write(m->trans, m->wbuf + m->wpos, m->wsize - m->wpos);
505 P9_DPRINTK(P9_DEBUG_MUX, "mux %p sent %d bytes\n", m, err);
506 if (err == -EAGAIN) {
507 clear_bit(Wworksched, &m->wsched);
508 return;
509 }
510
511 if (err < 0)
512 goto error;
513 else if (err == 0) {
514 err = -EREMOTEIO;
515 goto error;
516 }
517
518 m->wpos += err;
519 if (m->wpos == m->wsize)
520 m->wpos = m->wsize = 0;
521
522 if (m->wsize == 0 && !list_empty(&m->unsent_req_list)) {
523 if (test_and_clear_bit(Wpending, &m->wsched))
524 n = POLLOUT;
525 else
526 n = m->trans->poll(m->trans, NULL);
527
528 if (n & POLLOUT) {
529 P9_DPRINTK(P9_DEBUG_MUX, "schedule write work %p\n", m);
530 queue_work(p9_mux_wq, &m->wq);
531 } else
532 clear_bit(Wworksched, &m->wsched);
533 } else
534 clear_bit(Wworksched, &m->wsched);
535
536 return;
537
538 error:
539 p9_conn_cancel(m, err);
540 clear_bit(Wworksched, &m->wsched);
541 }
542
543 static void process_request(struct p9_conn *m, struct p9_req *req)
544 {
545 int ecode;
546 struct p9_str *ename;
547
548 if (!req->err && req->rcall->id == P9_RERROR) {
549 ecode = req->rcall->params.rerror.errno;
550 ename = &req->rcall->params.rerror.error;
551
552 P9_DPRINTK(P9_DEBUG_MUX, "Rerror %.*s\n", ename->len,
553 ename->str);
554
555 if (*m->extended)
556 req->err = -ecode;
557
558 if (!req->err) {
559 req->err = p9_errstr2errno(ename->str, ename->len);
560
561 if (!req->err) { /* string match failed */
562 PRINT_FCALL_ERROR("unknown error", req->rcall);
563 }
564
565 if (!req->err)
566 req->err = -ESERVERFAULT;
567 }
568 } else if (req->tcall && req->rcall->id != req->tcall->id + 1) {
569 P9_DPRINTK(P9_DEBUG_ERROR,
570 "fcall mismatch: expected %d, got %d\n",
571 req->tcall->id + 1, req->rcall->id);
572 if (!req->err)
573 req->err = -EIO;
574 }
575 }
576
577 /**
578 * p9_read_work - called when there is some data to be read from a transport
579 */
580 static void p9_read_work(struct work_struct *work)
581 {
582 int n, err;
583 struct p9_conn *m;
584 struct p9_req *req, *rptr, *rreq;
585 struct p9_fcall *rcall;
586 char *rbuf;
587
588 m = container_of(work, struct p9_conn, rq);
589
590 if (m->err < 0)
591 return;
592
593 rcall = NULL;
594 P9_DPRINTK(P9_DEBUG_MUX, "start mux %p pos %d\n", m, m->rpos);
595
596 if (!m->rcall) {
597 m->rcall =
598 kmalloc(sizeof(struct p9_fcall) + m->msize, GFP_KERNEL);
599 if (!m->rcall) {
600 err = -ENOMEM;
601 goto error;
602 }
603
604 m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
605 m->rpos = 0;
606 }
607
608 clear_bit(Rpending, &m->wsched);
609 err = m->trans->read(m->trans, m->rbuf + m->rpos, m->msize - m->rpos);
610 P9_DPRINTK(P9_DEBUG_MUX, "mux %p got %d bytes\n", m, err);
611 if (err == -EAGAIN) {
612 clear_bit(Rworksched, &m->wsched);
613 return;
614 }
615
616 if (err <= 0)
617 goto error;
618
619 m->rpos += err;
620 while (m->rpos > 4) {
621 n = le32_to_cpu(*(__le32 *) m->rbuf);
622 if (n >= m->msize) {
623 P9_DPRINTK(P9_DEBUG_ERROR,
624 "requested packet size too big: %d\n", n);
625 err = -EIO;
626 goto error;
627 }
628
629 if (m->rpos < n)
630 break;
631
632 err =
633 p9_deserialize_fcall(m->rbuf, n, m->rcall, *m->extended);
634 if (err < 0) {
635 goto error;
636 }
637
638 #ifdef CONFIG_NET_9P_DEBUG
639 if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
640 char buf[150];
641
642 p9_printfcall(buf, sizeof(buf), m->rcall,
643 *m->extended);
644 printk(KERN_NOTICE ">>> %p %s\n", m, buf);
645 }
646 #endif
647
648 rcall = m->rcall;
649 rbuf = m->rbuf;
650 if (m->rpos > n) {
651 m->rcall = kmalloc(sizeof(struct p9_fcall) + m->msize,
652 GFP_KERNEL);
653 if (!m->rcall) {
654 err = -ENOMEM;
655 goto error;
656 }
657
658 m->rbuf = (char *)m->rcall + sizeof(struct p9_fcall);
659 memmove(m->rbuf, rbuf + n, m->rpos - n);
660 m->rpos -= n;
661 } else {
662 m->rcall = NULL;
663 m->rbuf = NULL;
664 m->rpos = 0;
665 }
666
667 P9_DPRINTK(P9_DEBUG_MUX, "mux %p fcall id %d tag %d\n", m,
668 rcall->id, rcall->tag);
669
670 req = NULL;
671 spin_lock(&m->lock);
672 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
673 if (rreq->tag == rcall->tag) {
674 req = rreq;
675 if (req->flush != Flushing)
676 list_del(&req->req_list);
677 break;
678 }
679 }
680 spin_unlock(&m->lock);
681
682 if (req) {
683 req->rcall = rcall;
684 process_request(m, req);
685
686 if (req->flush != Flushing) {
687 if (req->cb)
688 (*req->cb) (req, req->cba);
689 else
690 kfree(req->rcall);
691
692 wake_up(&m->equeue);
693 }
694 } else {
695 if (err >= 0 && rcall->id != P9_RFLUSH)
696 P9_DPRINTK(P9_DEBUG_ERROR,
697 "unexpected response mux %p id %d tag %d\n",
698 m, rcall->id, rcall->tag);
699 kfree(rcall);
700 }
701 }
702
703 if (!list_empty(&m->req_list)) {
704 if (test_and_clear_bit(Rpending, &m->wsched))
705 n = POLLIN;
706 else
707 n = m->trans->poll(m->trans, NULL);
708
709 if (n & POLLIN) {
710 P9_DPRINTK(P9_DEBUG_MUX, "schedule read work %p\n", m);
711 queue_work(p9_mux_wq, &m->rq);
712 } else
713 clear_bit(Rworksched, &m->wsched);
714 } else
715 clear_bit(Rworksched, &m->wsched);
716
717 return;
718
719 error:
720 p9_conn_cancel(m, err);
721 clear_bit(Rworksched, &m->wsched);
722 }
723
724 /**
725 * p9_send_request - send 9P request
726 * The function can sleep until the request is scheduled for sending.
727 * The function can be interrupted. Return from the function is not
728 * a guarantee that the request is sent successfully. Can return errors
729 * that can be retrieved by PTR_ERR macros.
730 *
731 * @m: mux data
732 * @tc: request to be sent
733 * @cb: callback function to call when response is received
734 * @cba: parameter to pass to the callback function
735 */
736 static struct p9_req *p9_send_request(struct p9_conn *m,
737 struct p9_fcall *tc,
738 p9_conn_req_callback cb, void *cba)
739 {
740 int n;
741 struct p9_req *req;
742
743 P9_DPRINTK(P9_DEBUG_MUX, "mux %p task %p tcall %p id %d\n", m, current,
744 tc, tc->id);
745 if (m->err < 0)
746 return ERR_PTR(m->err);
747
748 req = kmalloc(sizeof(struct p9_req), GFP_KERNEL);
749 if (!req)
750 return ERR_PTR(-ENOMEM);
751
752 if (tc->id == P9_TVERSION)
753 n = P9_NOTAG;
754 else
755 n = p9_mux_get_tag(m);
756
757 if (n < 0)
758 return ERR_PTR(-ENOMEM);
759
760 p9_set_tag(tc, n);
761
762 #ifdef CONFIG_NET_9P_DEBUG
763 if ((p9_debug_level&P9_DEBUG_FCALL) == P9_DEBUG_FCALL) {
764 char buf[150];
765
766 p9_printfcall(buf, sizeof(buf), tc, *m->extended);
767 printk(KERN_NOTICE "<<< %p %s\n", m, buf);
768 }
769 #endif
770
771 spin_lock_init(&req->lock);
772 req->tag = n;
773 req->tcall = tc;
774 req->rcall = NULL;
775 req->err = 0;
776 req->cb = cb;
777 req->cba = cba;
778 req->flush = None;
779
780 spin_lock(&m->lock);
781 list_add_tail(&req->req_list, &m->unsent_req_list);
782 spin_unlock(&m->lock);
783
784 if (test_and_clear_bit(Wpending, &m->wsched))
785 n = POLLOUT;
786 else
787 n = m->trans->poll(m->trans, NULL);
788
789 if (n & POLLOUT && !test_and_set_bit(Wworksched, &m->wsched))
790 queue_work(p9_mux_wq, &m->wq);
791
792 return req;
793 }
794
795 static void p9_mux_free_request(struct p9_conn *m, struct p9_req *req)
796 {
797 p9_mux_put_tag(m, req->tag);
798 kfree(req);
799 }
800
801 static void p9_mux_flush_cb(struct p9_req *freq, void *a)
802 {
803 p9_conn_req_callback cb;
804 int tag;
805 struct p9_conn *m;
806 struct p9_req *req, *rreq, *rptr;
807
808 m = a;
809 P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p rc %p err %d oldtag %d\n", m,
810 freq->tcall, freq->rcall, freq->err,
811 freq->tcall->params.tflush.oldtag);
812
813 spin_lock(&m->lock);
814 cb = NULL;
815 tag = freq->tcall->params.tflush.oldtag;
816 req = NULL;
817 list_for_each_entry_safe(rreq, rptr, &m->req_list, req_list) {
818 if (rreq->tag == tag) {
819 req = rreq;
820 list_del(&req->req_list);
821 break;
822 }
823 }
824 spin_unlock(&m->lock);
825
826 if (req) {
827 spin_lock(&req->lock);
828 req->flush = Flushed;
829 spin_unlock(&req->lock);
830
831 if (req->cb)
832 (*req->cb) (req, req->cba);
833 else
834 kfree(req->rcall);
835
836 wake_up(&m->equeue);
837 }
838
839 kfree(freq->tcall);
840 kfree(freq->rcall);
841 p9_mux_free_request(m, freq);
842 }
843
844 static int
845 p9_mux_flush_request(struct p9_conn *m, struct p9_req *req)
846 {
847 struct p9_fcall *fc;
848 struct p9_req *rreq, *rptr;
849
850 P9_DPRINTK(P9_DEBUG_MUX, "mux %p req %p tag %d\n", m, req, req->tag);
851
852 /* if a response was received for a request, do nothing */
853 spin_lock(&req->lock);
854 if (req->rcall || req->err) {
855 spin_unlock(&req->lock);
856 P9_DPRINTK(P9_DEBUG_MUX,
857 "mux %p req %p response already received\n", m, req);
858 return 0;
859 }
860
861 req->flush = Flushing;
862 spin_unlock(&req->lock);
863
864 spin_lock(&m->lock);
865 /* if the request is not sent yet, just remove it from the list */
866 list_for_each_entry_safe(rreq, rptr, &m->unsent_req_list, req_list) {
867 if (rreq->tag == req->tag) {
868 P9_DPRINTK(P9_DEBUG_MUX,
869 "mux %p req %p request is not sent yet\n", m, req);
870 list_del(&rreq->req_list);
871 req->flush = Flushed;
872 spin_unlock(&m->lock);
873 if (req->cb)
874 (*req->cb) (req, req->cba);
875 return 0;
876 }
877 }
878 spin_unlock(&m->lock);
879
880 clear_thread_flag(TIF_SIGPENDING);
881 fc = p9_create_tflush(req->tag);
882 p9_send_request(m, fc, p9_mux_flush_cb, m);
883 return 1;
884 }
885
886 static void
887 p9_conn_rpc_cb(struct p9_req *req, void *a)
888 {
889 struct p9_mux_rpc *r;
890
891 P9_DPRINTK(P9_DEBUG_MUX, "req %p r %p\n", req, a);
892 r = a;
893 r->rcall = req->rcall;
894 r->err = req->err;
895
896 if (req->flush != None && !req->err)
897 r->err = -ERESTARTSYS;
898
899 wake_up(&r->wqueue);
900 }
901
902 /**
903 * p9_mux_rpc - sends 9P request and waits until a response is available.
904 * The function can be interrupted.
905 * @m: mux data
906 * @tc: request to be sent
907 * @rc: pointer where a pointer to the response is stored
908 */
909 int
910 p9_conn_rpc(struct p9_conn *m, struct p9_fcall *tc,
911 struct p9_fcall **rc)
912 {
913 int err, sigpending;
914 unsigned long flags;
915 struct p9_req *req;
916 struct p9_mux_rpc r;
917
918 r.err = 0;
919 r.tcall = tc;
920 r.rcall = NULL;
921 r.m = m;
922 init_waitqueue_head(&r.wqueue);
923
924 if (rc)
925 *rc = NULL;
926
927 sigpending = 0;
928 if (signal_pending(current)) {
929 sigpending = 1;
930 clear_thread_flag(TIF_SIGPENDING);
931 }
932
933 req = p9_send_request(m, tc, p9_conn_rpc_cb, &r);
934 if (IS_ERR(req)) {
935 err = PTR_ERR(req);
936 P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
937 return err;
938 }
939
940 err = wait_event_interruptible(r.wqueue, r.rcall != NULL || r.err < 0);
941 if (r.err < 0)
942 err = r.err;
943
944 if (err == -ERESTARTSYS && m->trans->status == Connected
945 && m->err == 0) {
946 if (p9_mux_flush_request(m, req)) {
947 /* wait until we get response of the flush message */
948 do {
949 clear_thread_flag(TIF_SIGPENDING);
950 err = wait_event_interruptible(r.wqueue,
951 r.rcall || r.err);
952 } while (!r.rcall && !r.err && err == -ERESTARTSYS &&
953 m->trans->status == Connected && !m->err);
954
955 err = -ERESTARTSYS;
956 }
957 sigpending = 1;
958 }
959
960 if (sigpending) {
961 spin_lock_irqsave(&current->sighand->siglock, flags);
962 recalc_sigpending();
963 spin_unlock_irqrestore(&current->sighand->siglock, flags);
964 }
965
966 if (rc)
967 *rc = r.rcall;
968 else
969 kfree(r.rcall);
970
971 p9_mux_free_request(m, req);
972 if (err > 0)
973 err = -EIO;
974
975 return err;
976 }
977 EXPORT_SYMBOL(p9_conn_rpc);
978
979 #ifdef P9_NONBLOCK
980 /**
981 * p9_conn_rpcnb - sends 9P request without waiting for response.
982 * @m: mux data
983 * @tc: request to be sent
984 * @cb: callback function to be called when response arrives
985 * @cba: value to pass to the callback function
986 */
987 int p9_conn_rpcnb(struct p9_conn *m, struct p9_fcall *tc,
988 p9_conn_req_callback cb, void *a)
989 {
990 int err;
991 struct p9_req *req;
992
993 req = p9_send_request(m, tc, cb, a);
994 if (IS_ERR(req)) {
995 err = PTR_ERR(req);
996 P9_DPRINTK(P9_DEBUG_MUX, "error %d\n", err);
997 return PTR_ERR(req);
998 }
999
1000 P9_DPRINTK(P9_DEBUG_MUX, "mux %p tc %p tag %d\n", m, tc, req->tag);
1001 return 0;
1002 }
1003 EXPORT_SYMBOL(p9_conn_rpcnb);
1004 #endif /* P9_NONBLOCK */
1005
1006 /**
1007 * p9_conn_cancel - cancel all pending requests with error
1008 * @m: mux data
1009 * @err: error code
1010 */
1011 void p9_conn_cancel(struct p9_conn *m, int err)
1012 {
1013 struct p9_req *req, *rtmp;
1014 LIST_HEAD(cancel_list);
1015
1016 P9_DPRINTK(P9_DEBUG_ERROR, "mux %p err %d\n", m, err);
1017 m->err = err;
1018 spin_lock(&m->lock);
1019 list_for_each_entry_safe(req, rtmp, &m->req_list, req_list) {
1020 list_move(&req->req_list, &cancel_list);
1021 }
1022 list_for_each_entry_safe(req, rtmp, &m->unsent_req_list, req_list) {
1023 list_move(&req->req_list, &cancel_list);
1024 }
1025 spin_unlock(&m->lock);
1026
1027 list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) {
1028 list_del(&req->req_list);
1029 if (!req->err)
1030 req->err = err;
1031
1032 if (req->cb)
1033 (*req->cb) (req, req->cba);
1034 else
1035 kfree(req->rcall);
1036 }
1037
1038 wake_up(&m->equeue);
1039 }
1040 EXPORT_SYMBOL(p9_conn_cancel);
1041
1042 static u16 p9_mux_get_tag(struct p9_conn *m)
1043 {
1044 int tag;
1045
1046 tag = p9_idpool_get(m->tagpool);
1047 if (tag < 0)
1048 return P9_NOTAG;
1049 else
1050 return (u16) tag;
1051 }
1052
1053 static void p9_mux_put_tag(struct p9_conn *m, u16 tag)
1054 {
1055 if (tag != P9_NOTAG && p9_idpool_check(tag, m->tagpool))
1056 p9_idpool_put(tag, m->tagpool);
1057 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree