diff options
author | Alex Zeffertt <alex.zeffertt@eu.citrix.com> | 2009-01-07 21:07:11 -0500 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-08 11:30:59 -0500 |
commit | 1107ba885e46964316c083d441d5dd185b6c9e49 (patch) | |
tree | 98cc3f81ad7ff554e10fc263abfb7727a438cc5a /drivers/xen/xenfs/xenbus.c | |
parent | d8220347da2a0639f5e1919a5af08f49cb37c24f (diff) |
xen: add xenfs to allow usermode <-> Xen interaction
The xenfs filesystem exports various interfaces to usermode. Initially
this exports a file to allow usermode to interact with xenbus/xenstore.
Traditionally this appeared in /proc/xen. Rather than extending procfs,
this patch adds a backward-compat mountpoint on /proc/xen, and provides
a xenfs filesystem which can be mounted there.
Signed-off-by: Alex Zeffertt <alex.zeffertt@eu.citrix.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/xen/xenfs/xenbus.c')
-rw-r--r-- | drivers/xen/xenfs/xenbus.c | 593 |
1 files changed, 593 insertions, 0 deletions
diff --git a/drivers/xen/xenfs/xenbus.c b/drivers/xen/xenfs/xenbus.c new file mode 100644 index 000000000000..875a4c59c594 --- /dev/null +++ b/drivers/xen/xenfs/xenbus.c | |||
@@ -0,0 +1,593 @@ | |||
1 | /* | ||
2 | * Driver giving user-space access to the kernel's xenbus connection | ||
3 | * to xenstore. | ||
4 | * | ||
5 | * Copyright (c) 2005, Christian Limpach | ||
6 | * Copyright (c) 2005, Rusty Russell, IBM Corporation | ||
7 | * | ||
8 | * This program is free software; you can redistribute it and/or | ||
9 | * modify it under the terms of the GNU General Public License version 2 | ||
10 | * as published by the Free Software Foundation; or, when distributed | ||
11 | * separately from the Linux kernel or incorporated into other | ||
12 | * software packages, subject to the following license: | ||
13 | * | ||
14 | * Permission is hereby granted, free of charge, to any person obtaining a copy | ||
15 | * of this source file (the "Software"), to deal in the Software without | ||
16 | * restriction, including without limitation the rights to use, copy, modify, | ||
17 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, | ||
18 | * and to permit persons to whom the Software is furnished to do so, subject to | ||
19 | * the following conditions: | ||
20 | * | ||
21 | * The above copyright notice and this permission notice shall be included in | ||
22 | * all copies or substantial portions of the Software. | ||
23 | * | ||
24 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | ||
25 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | ||
26 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | ||
27 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | ||
28 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | ||
29 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | ||
30 | * IN THE SOFTWARE. | ||
31 | * | ||
32 | * Changes: | ||
33 | * 2008-10-07 Alex Zeffertt Replaced /proc/xen/xenbus with xenfs filesystem | ||
34 | * and /proc/xen compatibility mount point. | ||
35 | * Turned xenfs into a loadable module. | ||
36 | */ | ||
37 | |||
38 | #include <linux/kernel.h> | ||
39 | #include <linux/errno.h> | ||
40 | #include <linux/uio.h> | ||
41 | #include <linux/notifier.h> | ||
42 | #include <linux/wait.h> | ||
43 | #include <linux/fs.h> | ||
44 | #include <linux/poll.h> | ||
45 | #include <linux/mutex.h> | ||
46 | #include <linux/spinlock.h> | ||
47 | #include <linux/mount.h> | ||
48 | #include <linux/pagemap.h> | ||
49 | #include <linux/uaccess.h> | ||
50 | #include <linux/init.h> | ||
51 | #include <linux/namei.h> | ||
52 | #include <linux/string.h> | ||
53 | |||
54 | #include "xenfs.h" | ||
55 | #include "../xenbus/xenbus_comms.h" | ||
56 | |||
57 | #include <xen/xenbus.h> | ||
58 | #include <asm/xen/hypervisor.h> | ||
59 | |||
60 | /* | ||
61 | * An element of a list of outstanding transactions, for which we're | ||
62 | * still waiting a reply. | ||
63 | */ | ||
64 | struct xenbus_transaction_holder { | ||
65 | struct list_head list; | ||
66 | struct xenbus_transaction handle; | ||
67 | }; | ||
68 | |||
69 | /* | ||
70 | * A buffer of data on the queue. | ||
71 | */ | ||
72 | struct read_buffer { | ||
73 | struct list_head list; | ||
74 | unsigned int cons; | ||
75 | unsigned int len; | ||
76 | char msg[]; | ||
77 | }; | ||
78 | |||
79 | struct xenbus_file_priv { | ||
80 | /* | ||
81 | * msgbuffer_mutex is held while partial requests are built up | ||
82 | * and complete requests are acted on. It therefore protects | ||
83 | * the "transactions" and "watches" lists, and the partial | ||
84 | * request length and buffer. | ||
85 | * | ||
86 | * reply_mutex protects the reply being built up to return to | ||
87 | * usermode. It nests inside msgbuffer_mutex but may be held | ||
88 | * alone during a watch callback. | ||
89 | */ | ||
90 | struct mutex msgbuffer_mutex; | ||
91 | |||
92 | /* In-progress transactions */ | ||
93 | struct list_head transactions; | ||
94 | |||
95 | /* Active watches. */ | ||
96 | struct list_head watches; | ||
97 | |||
98 | /* Partial request. */ | ||
99 | unsigned int len; | ||
100 | union { | ||
101 | struct xsd_sockmsg msg; | ||
102 | char buffer[PAGE_SIZE]; | ||
103 | } u; | ||
104 | |||
105 | /* Response queue. */ | ||
106 | struct mutex reply_mutex; | ||
107 | struct list_head read_buffers; | ||
108 | wait_queue_head_t read_waitq; | ||
109 | |||
110 | }; | ||
111 | |||
112 | /* Read out any raw xenbus messages queued up. */ | ||
113 | static ssize_t xenbus_file_read(struct file *filp, | ||
114 | char __user *ubuf, | ||
115 | size_t len, loff_t *ppos) | ||
116 | { | ||
117 | struct xenbus_file_priv *u = filp->private_data; | ||
118 | struct read_buffer *rb; | ||
119 | unsigned i; | ||
120 | int ret; | ||
121 | |||
122 | mutex_lock(&u->reply_mutex); | ||
123 | while (list_empty(&u->read_buffers)) { | ||
124 | mutex_unlock(&u->reply_mutex); | ||
125 | ret = wait_event_interruptible(u->read_waitq, | ||
126 | !list_empty(&u->read_buffers)); | ||
127 | if (ret) | ||
128 | return ret; | ||
129 | mutex_lock(&u->reply_mutex); | ||
130 | } | ||
131 | |||
132 | rb = list_entry(u->read_buffers.next, struct read_buffer, list); | ||
133 | i = 0; | ||
134 | while (i < len) { | ||
135 | unsigned sz = min((unsigned)len - i, rb->len - rb->cons); | ||
136 | |||
137 | ret = copy_to_user(ubuf + i, &rb->msg[rb->cons], sz); | ||
138 | |||
139 | i += sz - ret; | ||
140 | rb->cons += sz - ret; | ||
141 | |||
142 | if (ret != sz) { | ||
143 | if (i == 0) | ||
144 | i = -EFAULT; | ||
145 | goto out; | ||
146 | } | ||
147 | |||
148 | /* Clear out buffer if it has been consumed */ | ||
149 | if (rb->cons == rb->len) { | ||
150 | list_del(&rb->list); | ||
151 | kfree(rb); | ||
152 | if (list_empty(&u->read_buffers)) | ||
153 | break; | ||
154 | rb = list_entry(u->read_buffers.next, | ||
155 | struct read_buffer, list); | ||
156 | } | ||
157 | } | ||
158 | |||
159 | out: | ||
160 | mutex_unlock(&u->reply_mutex); | ||
161 | return i; | ||
162 | } | ||
163 | |||
164 | /* | ||
165 | * Add a buffer to the queue. Caller must hold the appropriate lock | ||
166 | * if the queue is not local. (Commonly the caller will build up | ||
167 | * multiple queued buffers on a temporary local list, and then add it | ||
168 | * to the appropriate list under lock once all the buffers have een | ||
169 | * successfully allocated.) | ||
170 | */ | ||
171 | static int queue_reply(struct list_head *queue, const void *data, size_t len) | ||
172 | { | ||
173 | struct read_buffer *rb; | ||
174 | |||
175 | if (len == 0) | ||
176 | return 0; | ||
177 | |||
178 | rb = kmalloc(sizeof(*rb) + len, GFP_KERNEL); | ||
179 | if (rb == NULL) | ||
180 | return -ENOMEM; | ||
181 | |||
182 | rb->cons = 0; | ||
183 | rb->len = len; | ||
184 | |||
185 | memcpy(rb->msg, data, len); | ||
186 | |||
187 | list_add_tail(&rb->list, queue); | ||
188 | return 0; | ||
189 | } | ||
190 | |||
191 | /* | ||
192 | * Free all the read_buffer s on a list. | ||
193 | * Caller must have sole reference to list. | ||
194 | */ | ||
195 | static void queue_cleanup(struct list_head *list) | ||
196 | { | ||
197 | struct read_buffer *rb; | ||
198 | |||
199 | while (!list_empty(list)) { | ||
200 | rb = list_entry(list->next, struct read_buffer, list); | ||
201 | list_del(list->next); | ||
202 | kfree(rb); | ||
203 | } | ||
204 | } | ||
205 | |||
206 | struct watch_adapter { | ||
207 | struct list_head list; | ||
208 | struct xenbus_watch watch; | ||
209 | struct xenbus_file_priv *dev_data; | ||
210 | char *token; | ||
211 | }; | ||
212 | |||
213 | static void free_watch_adapter(struct watch_adapter *watch) | ||
214 | { | ||
215 | kfree(watch->watch.node); | ||
216 | kfree(watch->token); | ||
217 | kfree(watch); | ||
218 | } | ||
219 | |||
220 | static struct watch_adapter *alloc_watch_adapter(const char *path, | ||
221 | const char *token) | ||
222 | { | ||
223 | struct watch_adapter *watch; | ||
224 | |||
225 | watch = kzalloc(sizeof(*watch), GFP_KERNEL); | ||
226 | if (watch == NULL) | ||
227 | goto out_fail; | ||
228 | |||
229 | watch->watch.node = kstrdup(path, GFP_KERNEL); | ||
230 | if (watch->watch.node == NULL) | ||
231 | goto out_free; | ||
232 | |||
233 | watch->token = kstrdup(token, GFP_KERNEL); | ||
234 | if (watch->token == NULL) | ||
235 | goto out_free; | ||
236 | |||
237 | return watch; | ||
238 | |||
239 | out_free: | ||
240 | free_watch_adapter(watch); | ||
241 | |||
242 | out_fail: | ||
243 | return NULL; | ||
244 | } | ||
245 | |||
246 | static void watch_fired(struct xenbus_watch *watch, | ||
247 | const char **vec, | ||
248 | unsigned int len) | ||
249 | { | ||
250 | struct watch_adapter *adap; | ||
251 | struct xsd_sockmsg hdr; | ||
252 | const char *path, *token; | ||
253 | int path_len, tok_len, body_len, data_len = 0; | ||
254 | int ret; | ||
255 | LIST_HEAD(staging_q); | ||
256 | |||
257 | adap = container_of(watch, struct watch_adapter, watch); | ||
258 | |||
259 | path = vec[XS_WATCH_PATH]; | ||
260 | token = adap->token; | ||
261 | |||
262 | path_len = strlen(path) + 1; | ||
263 | tok_len = strlen(token) + 1; | ||
264 | if (len > 2) | ||
265 | data_len = vec[len] - vec[2] + 1; | ||
266 | body_len = path_len + tok_len + data_len; | ||
267 | |||
268 | hdr.type = XS_WATCH_EVENT; | ||
269 | hdr.len = body_len; | ||
270 | |||
271 | mutex_lock(&adap->dev_data->reply_mutex); | ||
272 | |||
273 | ret = queue_reply(&staging_q, &hdr, sizeof(hdr)); | ||
274 | if (!ret) | ||
275 | ret = queue_reply(&staging_q, path, path_len); | ||
276 | if (!ret) | ||
277 | ret = queue_reply(&staging_q, token, tok_len); | ||
278 | if (!ret && len > 2) | ||
279 | ret = queue_reply(&staging_q, vec[2], data_len); | ||
280 | |||
281 | if (!ret) { | ||
282 | /* success: pass reply list onto watcher */ | ||
283 | list_splice_tail(&staging_q, &adap->dev_data->read_buffers); | ||
284 | wake_up(&adap->dev_data->read_waitq); | ||
285 | } else | ||
286 | queue_cleanup(&staging_q); | ||
287 | |||
288 | mutex_unlock(&adap->dev_data->reply_mutex); | ||
289 | } | ||
290 | |||
291 | static int xenbus_write_transaction(unsigned msg_type, | ||
292 | struct xenbus_file_priv *u) | ||
293 | { | ||
294 | int rc, ret; | ||
295 | void *reply; | ||
296 | struct xenbus_transaction_holder *trans = NULL; | ||
297 | LIST_HEAD(staging_q); | ||
298 | |||
299 | if (msg_type == XS_TRANSACTION_START) { | ||
300 | trans = kmalloc(sizeof(*trans), GFP_KERNEL); | ||
301 | if (!trans) { | ||
302 | rc = -ENOMEM; | ||
303 | goto out; | ||
304 | } | ||
305 | } | ||
306 | |||
307 | reply = xenbus_dev_request_and_reply(&u->u.msg); | ||
308 | if (IS_ERR(reply)) { | ||
309 | kfree(trans); | ||
310 | rc = PTR_ERR(reply); | ||
311 | goto out; | ||
312 | } | ||
313 | |||
314 | if (msg_type == XS_TRANSACTION_START) { | ||
315 | trans->handle.id = simple_strtoul(reply, NULL, 0); | ||
316 | |||
317 | list_add(&trans->list, &u->transactions); | ||
318 | } else if (msg_type == XS_TRANSACTION_END) { | ||
319 | list_for_each_entry(trans, &u->transactions, list) | ||
320 | if (trans->handle.id == u->u.msg.tx_id) | ||
321 | break; | ||
322 | BUG_ON(&trans->list == &u->transactions); | ||
323 | list_del(&trans->list); | ||
324 | |||
325 | kfree(trans); | ||
326 | } | ||
327 | |||
328 | mutex_lock(&u->reply_mutex); | ||
329 | ret = queue_reply(&staging_q, &u->u.msg, sizeof(u->u.msg)); | ||
330 | if (!ret) | ||
331 | ret = queue_reply(&staging_q, reply, u->u.msg.len); | ||
332 | if (!ret) { | ||
333 | list_splice_tail(&staging_q, &u->read_buffers); | ||
334 | wake_up(&u->read_waitq); | ||
335 | } else { | ||
336 | queue_cleanup(&staging_q); | ||
337 | rc = ret; | ||
338 | } | ||
339 | mutex_unlock(&u->reply_mutex); | ||
340 | |||
341 | kfree(reply); | ||
342 | |||
343 | out: | ||
344 | return rc; | ||
345 | } | ||
346 | |||
347 | static int xenbus_write_watch(unsigned msg_type, struct xenbus_file_priv *u) | ||
348 | { | ||
349 | struct watch_adapter *watch, *tmp_watch; | ||
350 | char *path, *token; | ||
351 | int err, rc; | ||
352 | LIST_HEAD(staging_q); | ||
353 | |||
354 | path = u->u.buffer + sizeof(u->u.msg); | ||
355 | token = memchr(path, 0, u->u.msg.len); | ||
356 | if (token == NULL) { | ||
357 | rc = -EILSEQ; | ||
358 | goto out; | ||
359 | } | ||
360 | token++; | ||
361 | |||
362 | if (msg_type == XS_WATCH) { | ||
363 | watch = alloc_watch_adapter(path, token); | ||
364 | if (watch == NULL) { | ||
365 | rc = -ENOMEM; | ||
366 | goto out; | ||
367 | } | ||
368 | |||
369 | watch->watch.callback = watch_fired; | ||
370 | watch->dev_data = u; | ||
371 | |||
372 | err = register_xenbus_watch(&watch->watch); | ||
373 | if (err) { | ||
374 | free_watch_adapter(watch); | ||
375 | rc = err; | ||
376 | goto out; | ||
377 | } | ||
378 | list_add(&watch->list, &u->watches); | ||
379 | } else { | ||
380 | list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) { | ||
381 | if (!strcmp(watch->token, token) && | ||
382 | !strcmp(watch->watch.node, path)) { | ||
383 | unregister_xenbus_watch(&watch->watch); | ||
384 | list_del(&watch->list); | ||
385 | free_watch_adapter(watch); | ||
386 | break; | ||
387 | } | ||
388 | } | ||
389 | } | ||
390 | |||
391 | /* Success. Synthesize a reply to say all is OK. */ | ||
392 | { | ||
393 | struct { | ||
394 | struct xsd_sockmsg hdr; | ||
395 | char body[3]; | ||
396 | } __packed reply = { | ||
397 | { | ||
398 | .type = msg_type, | ||
399 | .len = sizeof(reply.body) | ||
400 | }, | ||
401 | "OK" | ||
402 | }; | ||
403 | |||
404 | mutex_lock(&u->reply_mutex); | ||
405 | rc = queue_reply(&u->read_buffers, &reply, sizeof(reply)); | ||
406 | mutex_unlock(&u->reply_mutex); | ||
407 | } | ||
408 | |||
409 | out: | ||
410 | return rc; | ||
411 | } | ||
412 | |||
413 | static ssize_t xenbus_file_write(struct file *filp, | ||
414 | const char __user *ubuf, | ||
415 | size_t len, loff_t *ppos) | ||
416 | { | ||
417 | struct xenbus_file_priv *u = filp->private_data; | ||
418 | uint32_t msg_type; | ||
419 | int rc = len; | ||
420 | int ret; | ||
421 | LIST_HEAD(staging_q); | ||
422 | |||
423 | /* | ||
424 | * We're expecting usermode to be writing properly formed | ||
425 | * xenbus messages. If they write an incomplete message we | ||
426 | * buffer it up. Once it is complete, we act on it. | ||
427 | */ | ||
428 | |||
429 | /* | ||
430 | * Make sure concurrent writers can't stomp all over each | ||
431 | * other's messages and make a mess of our partial message | ||
432 | * buffer. We don't make any attemppt to stop multiple | ||
433 | * writers from making a mess of each other's incomplete | ||
434 | * messages; we're just trying to guarantee our own internal | ||
435 | * consistency and make sure that single writes are handled | ||
436 | * atomically. | ||
437 | */ | ||
438 | mutex_lock(&u->msgbuffer_mutex); | ||
439 | |||
440 | /* Get this out of the way early to avoid confusion */ | ||
441 | if (len == 0) | ||
442 | goto out; | ||
443 | |||
444 | /* Can't write a xenbus message larger we can buffer */ | ||
445 | if ((len + u->len) > sizeof(u->u.buffer)) { | ||
446 | /* On error, dump existing buffer */ | ||
447 | u->len = 0; | ||
448 | rc = -EINVAL; | ||
449 | goto out; | ||
450 | } | ||
451 | |||
452 | ret = copy_from_user(u->u.buffer + u->len, ubuf, len); | ||
453 | |||
454 | if (ret == len) { | ||
455 | rc = -EFAULT; | ||
456 | goto out; | ||
457 | } | ||
458 | |||
459 | /* Deal with a partial copy. */ | ||
460 | len -= ret; | ||
461 | rc = len; | ||
462 | |||
463 | u->len += len; | ||
464 | |||
465 | /* Return if we haven't got a full message yet */ | ||
466 | if (u->len < sizeof(u->u.msg)) | ||
467 | goto out; /* not even the header yet */ | ||
468 | |||
469 | /* If we're expecting a message that's larger than we can | ||
470 | possibly send, dump what we have and return an error. */ | ||
471 | if ((sizeof(u->u.msg) + u->u.msg.len) > sizeof(u->u.buffer)) { | ||
472 | rc = -E2BIG; | ||
473 | u->len = 0; | ||
474 | goto out; | ||
475 | } | ||
476 | |||
477 | if (u->len < (sizeof(u->u.msg) + u->u.msg.len)) | ||
478 | goto out; /* incomplete data portion */ | ||
479 | |||
480 | /* | ||
481 | * OK, now we have a complete message. Do something with it. | ||
482 | */ | ||
483 | |||
484 | msg_type = u->u.msg.type; | ||
485 | |||
486 | switch (msg_type) { | ||
487 | case XS_TRANSACTION_START: | ||
488 | case XS_TRANSACTION_END: | ||
489 | case XS_DIRECTORY: | ||
490 | case XS_READ: | ||
491 | case XS_GET_PERMS: | ||
492 | case XS_RELEASE: | ||
493 | case XS_GET_DOMAIN_PATH: | ||
494 | case XS_WRITE: | ||
495 | case XS_MKDIR: | ||
496 | case XS_RM: | ||
497 | case XS_SET_PERMS: | ||
498 | /* Send out a transaction */ | ||
499 | ret = xenbus_write_transaction(msg_type, u); | ||
500 | break; | ||
501 | |||
502 | case XS_WATCH: | ||
503 | case XS_UNWATCH: | ||
504 | /* (Un)Ask for some path to be watched for changes */ | ||
505 | ret = xenbus_write_watch(msg_type, u); | ||
506 | break; | ||
507 | |||
508 | default: | ||
509 | ret = -EINVAL; | ||
510 | break; | ||
511 | } | ||
512 | if (ret != 0) | ||
513 | rc = ret; | ||
514 | |||
515 | /* Buffered message consumed */ | ||
516 | u->len = 0; | ||
517 | |||
518 | out: | ||
519 | mutex_unlock(&u->msgbuffer_mutex); | ||
520 | return rc; | ||
521 | } | ||
522 | |||
523 | static int xenbus_file_open(struct inode *inode, struct file *filp) | ||
524 | { | ||
525 | struct xenbus_file_priv *u; | ||
526 | |||
527 | if (xen_store_evtchn == 0) | ||
528 | return -ENOENT; | ||
529 | |||
530 | nonseekable_open(inode, filp); | ||
531 | |||
532 | u = kzalloc(sizeof(*u), GFP_KERNEL); | ||
533 | if (u == NULL) | ||
534 | return -ENOMEM; | ||
535 | |||
536 | INIT_LIST_HEAD(&u->transactions); | ||
537 | INIT_LIST_HEAD(&u->watches); | ||
538 | INIT_LIST_HEAD(&u->read_buffers); | ||
539 | init_waitqueue_head(&u->read_waitq); | ||
540 | |||
541 | mutex_init(&u->reply_mutex); | ||
542 | mutex_init(&u->msgbuffer_mutex); | ||
543 | |||
544 | filp->private_data = u; | ||
545 | |||
546 | return 0; | ||
547 | } | ||
548 | |||
549 | static int xenbus_file_release(struct inode *inode, struct file *filp) | ||
550 | { | ||
551 | struct xenbus_file_priv *u = filp->private_data; | ||
552 | struct xenbus_transaction_holder *trans, *tmp; | ||
553 | struct watch_adapter *watch, *tmp_watch; | ||
554 | |||
555 | /* | ||
556 | * No need for locking here because there are no other users, | ||
557 | * by definition. | ||
558 | */ | ||
559 | |||
560 | list_for_each_entry_safe(trans, tmp, &u->transactions, list) { | ||
561 | xenbus_transaction_end(trans->handle, 1); | ||
562 | list_del(&trans->list); | ||
563 | kfree(trans); | ||
564 | } | ||
565 | |||
566 | list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) { | ||
567 | unregister_xenbus_watch(&watch->watch); | ||
568 | list_del(&watch->list); | ||
569 | free_watch_adapter(watch); | ||
570 | } | ||
571 | |||
572 | kfree(u); | ||
573 | |||
574 | return 0; | ||
575 | } | ||
576 | |||
577 | static unsigned int xenbus_file_poll(struct file *file, poll_table *wait) | ||
578 | { | ||
579 | struct xenbus_file_priv *u = file->private_data; | ||
580 | |||
581 | poll_wait(file, &u->read_waitq, wait); | ||
582 | if (!list_empty(&u->read_buffers)) | ||
583 | return POLLIN | POLLRDNORM; | ||
584 | return 0; | ||
585 | } | ||
586 | |||
587 | const struct file_operations xenbus_file_ops = { | ||
588 | .read = xenbus_file_read, | ||
589 | .write = xenbus_file_write, | ||
590 | .open = xenbus_file_open, | ||
591 | .release = xenbus_file_release, | ||
592 | .poll = xenbus_file_poll, | ||
593 | }; | ||