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Merge tag 'trace-printf-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace...
[drm/drm-misc.git] / drivers / block / nbd.c
blobb852050d8a96653007072569230af480ea8c8b53
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Network block device - make block devices work over TCP
4 *
5 * Note that you can not swap over this thing, yet. Seems to work but
6 * deadlocks sometimes - you can not swap over TCP in general.
7 *
8 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
9 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
10 *
11 * (part of code stolen from loop.c)
12 */
13
14 #define pr_fmt(fmt) "nbd: " fmt
15
16 #include <linux/major.h>
17
18 #include <linux/blkdev.h>
19 #include <linux/module.h>
20 #include <linux/init.h>
21 #include <linux/sched.h>
22 #include <linux/sched/mm.h>
23 #include <linux/fs.h>
24 #include <linux/bio.h>
25 #include <linux/stat.h>
26 #include <linux/errno.h>
27 #include <linux/file.h>
28 #include <linux/ioctl.h>
29 #include <linux/mutex.h>
30 #include <linux/compiler.h>
31 #include <linux/completion.h>
32 #include <linux/err.h>
33 #include <linux/kernel.h>
34 #include <linux/slab.h>
35 #include <net/sock.h>
36 #include <linux/net.h>
37 #include <linux/kthread.h>
38 #include <linux/types.h>
39 #include <linux/debugfs.h>
40 #include <linux/blk-mq.h>
41
42 #include <linux/uaccess.h>
43 #include <asm/types.h>
44
45 #include <linux/nbd.h>
46 #include <linux/nbd-netlink.h>
47 #include <net/genetlink.h>
48
49 #define CREATE_TRACE_POINTS
50 #include <trace/events/nbd.h>
51
52 static DEFINE_IDR(nbd_index_idr);
53 static DEFINE_MUTEX(nbd_index_mutex);
54 static struct workqueue_struct *nbd_del_wq;
55 static int nbd_total_devices = 0;
56
57 struct nbd_sock {
58 struct socket *sock;
59 struct mutex tx_lock;
60 struct request *pending;
61 int sent;
62 bool dead;
63 int fallback_index;
64 int cookie;
65 };
66
67 struct recv_thread_args {
68 struct work_struct work;
69 struct nbd_device *nbd;
70 struct nbd_sock *nsock;
71 int index;
72 };
73
74 struct link_dead_args {
75 struct work_struct work;
76 int index;
77 };
78
79 #define NBD_RT_TIMEDOUT 0
80 #define NBD_RT_DISCONNECT_REQUESTED 1
81 #define NBD_RT_DISCONNECTED 2
82 #define NBD_RT_HAS_PID_FILE 3
83 #define NBD_RT_HAS_CONFIG_REF 4
84 #define NBD_RT_BOUND 5
85 #define NBD_RT_DISCONNECT_ON_CLOSE 6
86 #define NBD_RT_HAS_BACKEND_FILE 7
87
88 #define NBD_DESTROY_ON_DISCONNECT 0
89 #define NBD_DISCONNECT_REQUESTED 1
90
91 struct nbd_config {
92 u32 flags;
93 unsigned long runtime_flags;
94 u64 dead_conn_timeout;
95
96 struct nbd_sock **socks;
97 int num_connections;
98 atomic_t live_connections;
99 wait_queue_head_t conn_wait;
100
101 atomic_t recv_threads;
102 wait_queue_head_t recv_wq;
103 unsigned int blksize_bits;
104 loff_t bytesize;
105 #if IS_ENABLED(CONFIG_DEBUG_FS)
106 struct dentry *dbg_dir;
107 #endif
108 };
109
110 static inline unsigned int nbd_blksize(struct nbd_config *config)
111 {
112 return 1u << config->blksize_bits;
113 }
114
115 struct nbd_device {
116 struct blk_mq_tag_set tag_set;
117
118 int index;
119 refcount_t config_refs;
120 refcount_t refs;
121 struct nbd_config *config;
122 struct mutex config_lock;
123 struct gendisk *disk;
124 struct workqueue_struct *recv_workq;
125 struct work_struct remove_work;
126
127 struct list_head list;
128 struct task_struct *task_setup;
129
130 unsigned long flags;
131 pid_t pid; /* pid of nbd-client, if attached */
132
133 char *backend;
134 };
135
136 #define NBD_CMD_REQUEUED 1
137 /*
138 * This flag will be set if nbd_queue_rq() succeed, and will be checked and
139 * cleared in completion. Both setting and clearing of the flag are protected
140 * by cmd->lock.
141 */
142 #define NBD_CMD_INFLIGHT 2
143
144 struct nbd_cmd {
145 struct nbd_device *nbd;
146 struct mutex lock;
147 int index;
148 int cookie;
149 int retries;
150 blk_status_t status;
151 unsigned long flags;
152 u32 cmd_cookie;
153 };
154
155 #if IS_ENABLED(CONFIG_DEBUG_FS)
156 static struct dentry *nbd_dbg_dir;
157 #endif
158
159 #define nbd_name(nbd) ((nbd)->disk->disk_name)
160
161 #define NBD_DEF_BLKSIZE_BITS 10
162
163 static unsigned int nbds_max = 16;
164 static int max_part = 16;
165 static int part_shift;
166
167 static int nbd_dev_dbg_init(struct nbd_device *nbd);
168 static void nbd_dev_dbg_close(struct nbd_device *nbd);
169 static void nbd_config_put(struct nbd_device *nbd);
170 static void nbd_connect_reply(struct genl_info *info, int index);
171 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
172 static void nbd_dead_link_work(struct work_struct *work);
173 static void nbd_disconnect_and_put(struct nbd_device *nbd);
174
175 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
176 {
177 return disk_to_dev(nbd->disk);
178 }
179
180 static void nbd_requeue_cmd(struct nbd_cmd *cmd)
181 {
182 struct request *req = blk_mq_rq_from_pdu(cmd);
183
184 lockdep_assert_held(&cmd->lock);
185
186 /*
187 * Clear INFLIGHT flag so that this cmd won't be completed in
188 * normal completion path
189 *
190 * INFLIGHT flag will be set when the cmd is queued to nbd next
191 * time.
192 */
193 __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
194
195 if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags))
196 blk_mq_requeue_request(req, true);
197 }
198
199 #define NBD_COOKIE_BITS 32
200
201 static u64 nbd_cmd_handle(struct nbd_cmd *cmd)
202 {
203 struct request *req = blk_mq_rq_from_pdu(cmd);
204 u32 tag = blk_mq_unique_tag(req);
205 u64 cookie = cmd->cmd_cookie;
206
207 return (cookie << NBD_COOKIE_BITS) | tag;
208 }
209
210 static u32 nbd_handle_to_tag(u64 handle)
211 {
212 return (u32)handle;
213 }
214
215 static u32 nbd_handle_to_cookie(u64 handle)
216 {
217 return (u32)(handle >> NBD_COOKIE_BITS);
218 }
219
220 static const char *nbdcmd_to_ascii(int cmd)
221 {
222 switch (cmd) {
223 case NBD_CMD_READ: return "read";
224 case NBD_CMD_WRITE: return "write";
225 case NBD_CMD_DISC: return "disconnect";
226 case NBD_CMD_FLUSH: return "flush";
227 case NBD_CMD_TRIM: return "trim/discard";
228 }
229 return "invalid";
230 }
231
232 static ssize_t pid_show(struct device *dev,
233 struct device_attribute *attr, char *buf)
234 {
235 struct gendisk *disk = dev_to_disk(dev);
236 struct nbd_device *nbd = disk->private_data;
237
238 return sprintf(buf, "%d\n", nbd->pid);
239 }
240
241 static const struct device_attribute pid_attr = {
242 .attr = { .name = "pid", .mode = 0444},
243 .show = pid_show,
244 };
245
246 static ssize_t backend_show(struct device *dev,
247 struct device_attribute *attr, char *buf)
248 {
249 struct gendisk *disk = dev_to_disk(dev);
250 struct nbd_device *nbd = disk->private_data;
251
252 return sprintf(buf, "%s\n", nbd->backend ?: "");
253 }
254
255 static const struct device_attribute backend_attr = {
256 .attr = { .name = "backend", .mode = 0444},
257 .show = backend_show,
258 };
259
260 static void nbd_dev_remove(struct nbd_device *nbd)
261 {
262 struct gendisk *disk = nbd->disk;
263
264 del_gendisk(disk);
265 blk_mq_free_tag_set(&nbd->tag_set);
266
267 /*
268 * Remove from idr after del_gendisk() completes, so if the same ID is
269 * reused, the following add_disk() will succeed.
270 */
271 mutex_lock(&nbd_index_mutex);
272 idr_remove(&nbd_index_idr, nbd->index);
273 mutex_unlock(&nbd_index_mutex);
274 destroy_workqueue(nbd->recv_workq);
275 put_disk(disk);
276 }
277
278 static void nbd_dev_remove_work(struct work_struct *work)
279 {
280 nbd_dev_remove(container_of(work, struct nbd_device, remove_work));
281 }
282
283 static void nbd_put(struct nbd_device *nbd)
284 {
285 if (!refcount_dec_and_test(&nbd->refs))
286 return;
287
288 /* Call del_gendisk() asynchrounously to prevent deadlock */
289 if (test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags))
290 queue_work(nbd_del_wq, &nbd->remove_work);
291 else
292 nbd_dev_remove(nbd);
293 }
294
295 static int nbd_disconnected(struct nbd_config *config)
296 {
297 return test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags) ||
298 test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
299 }
300
301 static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
302 int notify)
303 {
304 if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) {
305 struct link_dead_args *args;
306 args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO);
307 if (args) {
308 INIT_WORK(&args->work, nbd_dead_link_work);
309 args->index = nbd->index;
310 queue_work(system_wq, &args->work);
311 }
312 }
313 if (!nsock->dead) {
314 kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
315 if (atomic_dec_return(&nbd->config->live_connections) == 0) {
316 if (test_and_clear_bit(NBD_RT_DISCONNECT_REQUESTED,
317 &nbd->config->runtime_flags)) {
318 set_bit(NBD_RT_DISCONNECTED,
319 &nbd->config->runtime_flags);
320 dev_info(nbd_to_dev(nbd),
321 "Disconnected due to user request.\n");
322 }
323 }
324 }
325 nsock->dead = true;
326 nsock->pending = NULL;
327 nsock->sent = 0;
328 }
329
330 static int __nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
331 loff_t blksize)
332 {
333 struct queue_limits lim;
334 int error;
335
336 if (!blksize)
337 blksize = 1u << NBD_DEF_BLKSIZE_BITS;
338
339 if (blk_validate_block_size(blksize))
340 return -EINVAL;
341
342 if (bytesize < 0)
343 return -EINVAL;
344
345 nbd->config->bytesize = bytesize;
346 nbd->config->blksize_bits = __ffs(blksize);
347
348 if (!nbd->pid)
349 return 0;
350
351 lim = queue_limits_start_update(nbd->disk->queue);
352 if (nbd->config->flags & NBD_FLAG_SEND_TRIM)
353 lim.max_hw_discard_sectors = UINT_MAX >> SECTOR_SHIFT;
354 else
355 lim.max_hw_discard_sectors = 0;
356 if (!(nbd->config->flags & NBD_FLAG_SEND_FLUSH)) {
357 lim.features &= ~(BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA);
358 } else if (nbd->config->flags & NBD_FLAG_SEND_FUA) {
359 lim.features |= BLK_FEAT_WRITE_CACHE | BLK_FEAT_FUA;
360 } else {
361 lim.features |= BLK_FEAT_WRITE_CACHE;
362 lim.features &= ~BLK_FEAT_FUA;
363 }
364 if (nbd->config->flags & NBD_FLAG_ROTATIONAL)
365 lim.features |= BLK_FEAT_ROTATIONAL;
366 if (nbd->config->flags & NBD_FLAG_SEND_WRITE_ZEROES)
367 lim.max_write_zeroes_sectors = UINT_MAX >> SECTOR_SHIFT;
368
369 lim.logical_block_size = blksize;
370 lim.physical_block_size = blksize;
371 error = queue_limits_commit_update(nbd->disk->queue, &lim);
372 if (error)
373 return error;
374
375 if (max_part)
376 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
377 if (!set_capacity_and_notify(nbd->disk, bytesize >> 9))
378 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
379 return 0;
380 }
381
382 static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
383 loff_t blksize)
384 {
385 int error;
386
387 blk_mq_freeze_queue(nbd->disk->queue);
388 error = __nbd_set_size(nbd, bytesize, blksize);
389 blk_mq_unfreeze_queue(nbd->disk->queue);
390
391 return error;
392 }
393
394 static void nbd_complete_rq(struct request *req)
395 {
396 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
397
398 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", req,
399 cmd->status ? "failed" : "done");
400
401 blk_mq_end_request(req, cmd->status);
402 }
403
404 /*
405 * Forcibly shutdown the socket causing all listeners to error
406 */
407 static void sock_shutdown(struct nbd_device *nbd)
408 {
409 struct nbd_config *config = nbd->config;
410 int i;
411
412 if (config->num_connections == 0)
413 return;
414 if (test_and_set_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
415 return;
416
417 for (i = 0; i < config->num_connections; i++) {
418 struct nbd_sock *nsock = config->socks[i];
419 mutex_lock(&nsock->tx_lock);
420 nbd_mark_nsock_dead(nbd, nsock, 0);
421 mutex_unlock(&nsock->tx_lock);
422 }
423 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
424 }
425
426 static u32 req_to_nbd_cmd_type(struct request *req)
427 {
428 switch (req_op(req)) {
429 case REQ_OP_DISCARD:
430 return NBD_CMD_TRIM;
431 case REQ_OP_FLUSH:
432 return NBD_CMD_FLUSH;
433 case REQ_OP_WRITE:
434 return NBD_CMD_WRITE;
435 case REQ_OP_READ:
436 return NBD_CMD_READ;
437 case REQ_OP_WRITE_ZEROES:
438 return NBD_CMD_WRITE_ZEROES;
439 default:
440 return U32_MAX;
441 }
442 }
443
444 static struct nbd_config *nbd_get_config_unlocked(struct nbd_device *nbd)
445 {
446 if (refcount_inc_not_zero(&nbd->config_refs)) {
447 /*
448 * Add smp_mb__after_atomic to ensure that reading nbd->config_refs
449 * and reading nbd->config is ordered. The pair is the barrier in
450 * nbd_alloc_and_init_config(), avoid nbd->config_refs is set
451 * before nbd->config.
452 */
453 smp_mb__after_atomic();
454 return nbd->config;
455 }
456
457 return NULL;
458 }
459
460 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req)
461 {
462 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
463 struct nbd_device *nbd = cmd->nbd;
464 struct nbd_config *config;
465
466 if (!mutex_trylock(&cmd->lock))
467 return BLK_EH_RESET_TIMER;
468
469 if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
470 mutex_unlock(&cmd->lock);
471 return BLK_EH_DONE;
472 }
473
474 config = nbd_get_config_unlocked(nbd);
475 if (!config) {
476 cmd->status = BLK_STS_TIMEOUT;
477 __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
478 mutex_unlock(&cmd->lock);
479 goto done;
480 }
481
482 if (config->num_connections > 1 ||
483 (config->num_connections == 1 && nbd->tag_set.timeout)) {
484 dev_err_ratelimited(nbd_to_dev(nbd),
485 "Connection timed out, retrying (%d/%d alive)\n",
486 atomic_read(&config->live_connections),
487 config->num_connections);
488 /*
489 * Hooray we have more connections, requeue this IO, the submit
490 * path will put it on a real connection. Or if only one
491 * connection is configured, the submit path will wait util
492 * a new connection is reconfigured or util dead timeout.
493 */
494 if (config->socks) {
495 if (cmd->index < config->num_connections) {
496 struct nbd_sock *nsock =
497 config->socks[cmd->index];
498 mutex_lock(&nsock->tx_lock);
499 /* We can have multiple outstanding requests, so
500 * we don't want to mark the nsock dead if we've
501 * already reconnected with a new socket, so
502 * only mark it dead if its the same socket we
503 * were sent out on.
504 */
505 if (cmd->cookie == nsock->cookie)
506 nbd_mark_nsock_dead(nbd, nsock, 1);
507 mutex_unlock(&nsock->tx_lock);
508 }
509 nbd_requeue_cmd(cmd);
510 mutex_unlock(&cmd->lock);
511 nbd_config_put(nbd);
512 return BLK_EH_DONE;
513 }
514 }
515
516 if (!nbd->tag_set.timeout) {
517 /*
518 * Userspace sets timeout=0 to disable socket disconnection,
519 * so just warn and reset the timer.
520 */
521 struct nbd_sock *nsock = config->socks[cmd->index];
522 cmd->retries++;
523 dev_info(nbd_to_dev(nbd), "Possible stuck request %p: control (%s@%llu,%uB). Runtime %u seconds\n",
524 req, nbdcmd_to_ascii(req_to_nbd_cmd_type(req)),
525 (unsigned long long)blk_rq_pos(req) << 9,
526 blk_rq_bytes(req), (req->timeout / HZ) * cmd->retries);
527
528 mutex_lock(&nsock->tx_lock);
529 if (cmd->cookie != nsock->cookie) {
530 nbd_requeue_cmd(cmd);
531 mutex_unlock(&nsock->tx_lock);
532 mutex_unlock(&cmd->lock);
533 nbd_config_put(nbd);
534 return BLK_EH_DONE;
535 }
536 mutex_unlock(&nsock->tx_lock);
537 mutex_unlock(&cmd->lock);
538 nbd_config_put(nbd);
539 return BLK_EH_RESET_TIMER;
540 }
541
542 dev_err_ratelimited(nbd_to_dev(nbd), "Connection timed out\n");
543 set_bit(NBD_RT_TIMEDOUT, &config->runtime_flags);
544 cmd->status = BLK_STS_IOERR;
545 __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
546 mutex_unlock(&cmd->lock);
547 sock_shutdown(nbd);
548 nbd_config_put(nbd);
549 done:
550 blk_mq_complete_request(req);
551 return BLK_EH_DONE;
552 }
553
554 static int __sock_xmit(struct nbd_device *nbd, struct socket *sock, int send,
555 struct iov_iter *iter, int msg_flags, int *sent)
556 {
557 int result;
558 struct msghdr msg = {} ;
559 unsigned int noreclaim_flag;
560
561 if (unlikely(!sock)) {
562 dev_err_ratelimited(disk_to_dev(nbd->disk),
563 "Attempted %s on closed socket in sock_xmit\n",
564 (send ? "send" : "recv"));
565 return -EINVAL;
566 }
567
568 msg.msg_iter = *iter;
569
570 noreclaim_flag = memalloc_noreclaim_save();
571 do {
572 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
573 sock->sk->sk_use_task_frag = false;
574 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
575
576 if (send)
577 result = sock_sendmsg(sock, &msg);
578 else
579 result = sock_recvmsg(sock, &msg, msg.msg_flags);
580
581 if (result <= 0) {
582 if (result == 0)
583 result = -EPIPE; /* short read */
584 break;
585 }
586 if (sent)
587 *sent += result;
588 } while (msg_data_left(&msg));
589
590 memalloc_noreclaim_restore(noreclaim_flag);
591
592 return result;
593 }
594
595 /*
596 * Send or receive packet. Return a positive value on success and
597 * negtive value on failure, and never return 0.
598 */
599 static int sock_xmit(struct nbd_device *nbd, int index, int send,
600 struct iov_iter *iter, int msg_flags, int *sent)
601 {
602 struct nbd_config *config = nbd->config;
603 struct socket *sock = config->socks[index]->sock;
604
605 return __sock_xmit(nbd, sock, send, iter, msg_flags, sent);
606 }
607
608 /*
609 * Different settings for sk->sk_sndtimeo can result in different return values
610 * if there is a signal pending when we enter sendmsg, because reasons?
611 */
612 static inline int was_interrupted(int result)
613 {
614 return result == -ERESTARTSYS || result == -EINTR;
615 }
616
617 /*
618 * Returns BLK_STS_RESOURCE if the caller should retry after a delay.
619 * Returns BLK_STS_IOERR if sending failed.
620 */
621 static blk_status_t nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd,
622 int index)
623 {
624 struct request *req = blk_mq_rq_from_pdu(cmd);
625 struct nbd_config *config = nbd->config;
626 struct nbd_sock *nsock = config->socks[index];
627 int result;
628 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
629 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
630 struct iov_iter from;
631 struct bio *bio;
632 u64 handle;
633 u32 type;
634 u32 nbd_cmd_flags = 0;
635 int sent = nsock->sent, skip = 0;
636
637 lockdep_assert_held(&cmd->lock);
638 lockdep_assert_held(&nsock->tx_lock);
639
640 iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
641
642 type = req_to_nbd_cmd_type(req);
643 if (type == U32_MAX)
644 return BLK_STS_IOERR;
645
646 if (rq_data_dir(req) == WRITE &&
647 (config->flags & NBD_FLAG_READ_ONLY)) {
648 dev_err_ratelimited(disk_to_dev(nbd->disk),
649 "Write on read-only\n");
650 return BLK_STS_IOERR;
651 }
652
653 if (req->cmd_flags & REQ_FUA)
654 nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
655 if ((req->cmd_flags & REQ_NOUNMAP) && (type == NBD_CMD_WRITE_ZEROES))
656 nbd_cmd_flags |= NBD_CMD_FLAG_NO_HOLE;
657
658 /* We did a partial send previously, and we at least sent the whole
659 * request struct, so just go and send the rest of the pages in the
660 * request.
661 */
662 if (sent) {
663 if (sent >= sizeof(request)) {
664 skip = sent - sizeof(request);
665
666 /* initialize handle for tracing purposes */
667 handle = nbd_cmd_handle(cmd);
668
669 goto send_pages;
670 }
671 iov_iter_advance(&from, sent);
672 } else {
673 cmd->cmd_cookie++;
674 }
675 cmd->index = index;
676 cmd->cookie = nsock->cookie;
677 cmd->retries = 0;
678 request.type = htonl(type | nbd_cmd_flags);
679 if (type != NBD_CMD_FLUSH) {
680 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
681 request.len = htonl(blk_rq_bytes(req));
682 }
683 handle = nbd_cmd_handle(cmd);
684 request.cookie = cpu_to_be64(handle);
685
686 trace_nbd_send_request(&request, nbd->index, blk_mq_rq_from_pdu(cmd));
687
688 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
689 req, nbdcmd_to_ascii(type),
690 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
691 result = sock_xmit(nbd, index, 1, &from,
692 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
693 trace_nbd_header_sent(req, handle);
694 if (result < 0) {
695 if (was_interrupted(result)) {
696 /* If we haven't sent anything we can just return BUSY,
697 * however if we have sent something we need to make
698 * sure we only allow this req to be sent until we are
699 * completely done.
700 */
701 if (sent) {
702 nsock->pending = req;
703 nsock->sent = sent;
704 }
705 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
706 return BLK_STS_RESOURCE;
707 }
708 dev_err_ratelimited(disk_to_dev(nbd->disk),
709 "Send control failed (result %d)\n", result);
710 goto requeue;
711 }
712 send_pages:
713 if (type != NBD_CMD_WRITE)
714 goto out;
715
716 bio = req->bio;
717 while (bio) {
718 struct bio *next = bio->bi_next;
719 struct bvec_iter iter;
720 struct bio_vec bvec;
721
722 bio_for_each_segment(bvec, bio, iter) {
723 bool is_last = !next && bio_iter_last(bvec, iter);
724 int flags = is_last ? 0 : MSG_MORE;
725
726 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
727 req, bvec.bv_len);
728 iov_iter_bvec(&from, ITER_SOURCE, &bvec, 1, bvec.bv_len);
729 if (skip) {
730 if (skip >= iov_iter_count(&from)) {
731 skip -= iov_iter_count(&from);
732 continue;
733 }
734 iov_iter_advance(&from, skip);
735 skip = 0;
736 }
737 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
738 if (result < 0) {
739 if (was_interrupted(result)) {
740 /* We've already sent the header, we
741 * have no choice but to set pending and
742 * return BUSY.
743 */
744 nsock->pending = req;
745 nsock->sent = sent;
746 set_bit(NBD_CMD_REQUEUED, &cmd->flags);
747 return BLK_STS_RESOURCE;
748 }
749 dev_err(disk_to_dev(nbd->disk),
750 "Send data failed (result %d)\n",
751 result);
752 goto requeue;
753 }
754 /*
755 * The completion might already have come in,
756 * so break for the last one instead of letting
757 * the iterator do it. This prevents use-after-free
758 * of the bio.
759 */
760 if (is_last)
761 break;
762 }
763 bio = next;
764 }
765 out:
766 trace_nbd_payload_sent(req, handle);
767 nsock->pending = NULL;
768 nsock->sent = 0;
769 __set_bit(NBD_CMD_INFLIGHT, &cmd->flags);
770 return BLK_STS_OK;
771
772 requeue:
773 /* retry on a different socket */
774 dev_err_ratelimited(disk_to_dev(nbd->disk),
775 "Request send failed, requeueing\n");
776 nbd_mark_nsock_dead(nbd, nsock, 1);
777 nbd_requeue_cmd(cmd);
778 return BLK_STS_OK;
779 }
780
781 static int nbd_read_reply(struct nbd_device *nbd, struct socket *sock,
782 struct nbd_reply *reply)
783 {
784 struct kvec iov = {.iov_base = reply, .iov_len = sizeof(*reply)};
785 struct iov_iter to;
786 int result;
787
788 reply->magic = 0;
789 iov_iter_kvec(&to, ITER_DEST, &iov, 1, sizeof(*reply));
790 result = __sock_xmit(nbd, sock, 0, &to, MSG_WAITALL, NULL);
791 if (result < 0) {
792 if (!nbd_disconnected(nbd->config))
793 dev_err(disk_to_dev(nbd->disk),
794 "Receive control failed (result %d)\n", result);
795 return result;
796 }
797
798 if (ntohl(reply->magic) != NBD_REPLY_MAGIC) {
799 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
800 (unsigned long)ntohl(reply->magic));
801 return -EPROTO;
802 }
803
804 return 0;
805 }
806
807 /* NULL returned = something went wrong, inform userspace */
808 static struct nbd_cmd *nbd_handle_reply(struct nbd_device *nbd, int index,
809 struct nbd_reply *reply)
810 {
811 int result;
812 struct nbd_cmd *cmd;
813 struct request *req = NULL;
814 u64 handle;
815 u16 hwq;
816 u32 tag;
817 int ret = 0;
818
819 handle = be64_to_cpu(reply->cookie);
820 tag = nbd_handle_to_tag(handle);
821 hwq = blk_mq_unique_tag_to_hwq(tag);
822 if (hwq < nbd->tag_set.nr_hw_queues)
823 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
824 blk_mq_unique_tag_to_tag(tag));
825 if (!req || !blk_mq_request_started(req)) {
826 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
827 tag, req);
828 return ERR_PTR(-ENOENT);
829 }
830 trace_nbd_header_received(req, handle);
831 cmd = blk_mq_rq_to_pdu(req);
832
833 mutex_lock(&cmd->lock);
834 if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
835 dev_err(disk_to_dev(nbd->disk), "Suspicious reply %d (status %u flags %lu)",
836 tag, cmd->status, cmd->flags);
837 ret = -ENOENT;
838 goto out;
839 }
840 if (cmd->index != index) {
841 dev_err(disk_to_dev(nbd->disk), "Unexpected reply %d from different sock %d (expected %d)",
842 tag, index, cmd->index);
843 ret = -ENOENT;
844 goto out;
845 }
846 if (cmd->cmd_cookie != nbd_handle_to_cookie(handle)) {
847 dev_err(disk_to_dev(nbd->disk), "Double reply on req %p, cmd_cookie %u, handle cookie %u\n",
848 req, cmd->cmd_cookie, nbd_handle_to_cookie(handle));
849 ret = -ENOENT;
850 goto out;
851 }
852 if (cmd->status != BLK_STS_OK) {
853 dev_err(disk_to_dev(nbd->disk), "Command already handled %p\n",
854 req);
855 ret = -ENOENT;
856 goto out;
857 }
858 if (test_bit(NBD_CMD_REQUEUED, &cmd->flags)) {
859 dev_err(disk_to_dev(nbd->disk), "Raced with timeout on req %p\n",
860 req);
861 ret = -ENOENT;
862 goto out;
863 }
864 if (ntohl(reply->error)) {
865 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
866 ntohl(reply->error));
867 cmd->status = BLK_STS_IOERR;
868 goto out;
869 }
870
871 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", req);
872 if (rq_data_dir(req) != WRITE) {
873 struct req_iterator iter;
874 struct bio_vec bvec;
875 struct iov_iter to;
876
877 rq_for_each_segment(bvec, req, iter) {
878 iov_iter_bvec(&to, ITER_DEST, &bvec, 1, bvec.bv_len);
879 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
880 if (result < 0) {
881 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
882 result);
883 /*
884 * If we've disconnected, we need to make sure we
885 * complete this request, otherwise error out
886 * and let the timeout stuff handle resubmitting
887 * this request onto another connection.
888 */
889 if (nbd_disconnected(nbd->config)) {
890 cmd->status = BLK_STS_IOERR;
891 goto out;
892 }
893 ret = -EIO;
894 goto out;
895 }
896 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
897 req, bvec.bv_len);
898 }
899 }
900 out:
901 trace_nbd_payload_received(req, handle);
902 mutex_unlock(&cmd->lock);
903 return ret ? ERR_PTR(ret) : cmd;
904 }
905
906 static void recv_work(struct work_struct *work)
907 {
908 struct recv_thread_args *args = container_of(work,
909 struct recv_thread_args,
910 work);
911 struct nbd_device *nbd = args->nbd;
912 struct nbd_config *config = nbd->config;
913 struct request_queue *q = nbd->disk->queue;
914 struct nbd_sock *nsock = args->nsock;
915 struct nbd_cmd *cmd;
916 struct request *rq;
917
918 while (1) {
919 struct nbd_reply reply;
920
921 if (nbd_read_reply(nbd, nsock->sock, &reply))
922 break;
923
924 /*
925 * Grab .q_usage_counter so request pool won't go away, then no
926 * request use-after-free is possible during nbd_handle_reply().
927 * If queue is frozen, there won't be any inflight requests, we
928 * needn't to handle the incoming garbage message.
929 */
930 if (!percpu_ref_tryget(&q->q_usage_counter)) {
931 dev_err(disk_to_dev(nbd->disk), "%s: no io inflight\n",
932 __func__);
933 break;
934 }
935
936 cmd = nbd_handle_reply(nbd, args->index, &reply);
937 if (IS_ERR(cmd)) {
938 percpu_ref_put(&q->q_usage_counter);
939 break;
940 }
941
942 rq = blk_mq_rq_from_pdu(cmd);
943 if (likely(!blk_should_fake_timeout(rq->q))) {
944 bool complete;
945
946 mutex_lock(&cmd->lock);
947 complete = __test_and_clear_bit(NBD_CMD_INFLIGHT,
948 &cmd->flags);
949 mutex_unlock(&cmd->lock);
950 if (complete)
951 blk_mq_complete_request(rq);
952 }
953 percpu_ref_put(&q->q_usage_counter);
954 }
955
956 mutex_lock(&nsock->tx_lock);
957 nbd_mark_nsock_dead(nbd, nsock, 1);
958 mutex_unlock(&nsock->tx_lock);
959
960 nbd_config_put(nbd);
961 atomic_dec(&config->recv_threads);
962 wake_up(&config->recv_wq);
963 kfree(args);
964 }
965
966 static bool nbd_clear_req(struct request *req, void *data)
967 {
968 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
969
970 /* don't abort one completed request */
971 if (blk_mq_request_completed(req))
972 return true;
973
974 mutex_lock(&cmd->lock);
975 if (!__test_and_clear_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
976 mutex_unlock(&cmd->lock);
977 return true;
978 }
979 cmd->status = BLK_STS_IOERR;
980 mutex_unlock(&cmd->lock);
981
982 blk_mq_complete_request(req);
983 return true;
984 }
985
986 static void nbd_clear_que(struct nbd_device *nbd)
987 {
988 blk_mq_quiesce_queue(nbd->disk->queue);
989 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
990 blk_mq_unquiesce_queue(nbd->disk->queue);
991 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
992 }
993
994 static int find_fallback(struct nbd_device *nbd, int index)
995 {
996 struct nbd_config *config = nbd->config;
997 int new_index = -1;
998 struct nbd_sock *nsock = config->socks[index];
999 int fallback = nsock->fallback_index;
1000
1001 if (test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags))
1002 return new_index;
1003
1004 if (config->num_connections <= 1) {
1005 dev_err_ratelimited(disk_to_dev(nbd->disk),
1006 "Dead connection, failed to find a fallback\n");
1007 return new_index;
1008 }
1009
1010 if (fallback >= 0 && fallback < config->num_connections &&
1011 !config->socks[fallback]->dead)
1012 return fallback;
1013
1014 if (nsock->fallback_index < 0 ||
1015 nsock->fallback_index >= config->num_connections ||
1016 config->socks[nsock->fallback_index]->dead) {
1017 int i;
1018 for (i = 0; i < config->num_connections; i++) {
1019 if (i == index)
1020 continue;
1021 if (!config->socks[i]->dead) {
1022 new_index = i;
1023 break;
1024 }
1025 }
1026 nsock->fallback_index = new_index;
1027 if (new_index < 0) {
1028 dev_err_ratelimited(disk_to_dev(nbd->disk),
1029 "Dead connection, failed to find a fallback\n");
1030 return new_index;
1031 }
1032 }
1033 new_index = nsock->fallback_index;
1034 return new_index;
1035 }
1036
1037 static int wait_for_reconnect(struct nbd_device *nbd)
1038 {
1039 struct nbd_config *config = nbd->config;
1040 if (!config->dead_conn_timeout)
1041 return 0;
1042
1043 if (!wait_event_timeout(config->conn_wait,
1044 test_bit(NBD_RT_DISCONNECTED,
1045 &config->runtime_flags) ||
1046 atomic_read(&config->live_connections) > 0,
1047 config->dead_conn_timeout))
1048 return 0;
1049
1050 return !test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
1051 }
1052
1053 static blk_status_t nbd_handle_cmd(struct nbd_cmd *cmd, int index)
1054 {
1055 struct request *req = blk_mq_rq_from_pdu(cmd);
1056 struct nbd_device *nbd = cmd->nbd;
1057 struct nbd_config *config;
1058 struct nbd_sock *nsock;
1059 blk_status_t ret;
1060
1061 lockdep_assert_held(&cmd->lock);
1062
1063 config = nbd_get_config_unlocked(nbd);
1064 if (!config) {
1065 dev_err_ratelimited(disk_to_dev(nbd->disk),
1066 "Socks array is empty\n");
1067 return BLK_STS_IOERR;
1068 }
1069
1070 if (index >= config->num_connections) {
1071 dev_err_ratelimited(disk_to_dev(nbd->disk),
1072 "Attempted send on invalid socket\n");
1073 nbd_config_put(nbd);
1074 return BLK_STS_IOERR;
1075 }
1076 cmd->status = BLK_STS_OK;
1077 again:
1078 nsock = config->socks[index];
1079 mutex_lock(&nsock->tx_lock);
1080 if (nsock->dead) {
1081 int old_index = index;
1082 index = find_fallback(nbd, index);
1083 mutex_unlock(&nsock->tx_lock);
1084 if (index < 0) {
1085 if (wait_for_reconnect(nbd)) {
1086 index = old_index;
1087 goto again;
1088 }
1089 /* All the sockets should already be down at this point,
1090 * we just want to make sure that DISCONNECTED is set so
1091 * any requests that come in that were queue'ed waiting
1092 * for the reconnect timer don't trigger the timer again
1093 * and instead just error out.
1094 */
1095 sock_shutdown(nbd);
1096 nbd_config_put(nbd);
1097 return BLK_STS_IOERR;
1098 }
1099 goto again;
1100 }
1101
1102 /* Handle the case that we have a pending request that was partially
1103 * transmitted that _has_ to be serviced first. We need to call requeue
1104 * here so that it gets put _after_ the request that is already on the
1105 * dispatch list.
1106 */
1107 blk_mq_start_request(req);
1108 if (unlikely(nsock->pending && nsock->pending != req)) {
1109 nbd_requeue_cmd(cmd);
1110 ret = BLK_STS_OK;
1111 goto out;
1112 }
1113 ret = nbd_send_cmd(nbd, cmd, index);
1114 out:
1115 mutex_unlock(&nsock->tx_lock);
1116 nbd_config_put(nbd);
1117 return ret;
1118 }
1119
1120 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
1121 const struct blk_mq_queue_data *bd)
1122 {
1123 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
1124 blk_status_t ret;
1125
1126 /*
1127 * Since we look at the bio's to send the request over the network we
1128 * need to make sure the completion work doesn't mark this request done
1129 * before we are done doing our send. This keeps us from dereferencing
1130 * freed data if we have particularly fast completions (ie we get the
1131 * completion before we exit sock_xmit on the last bvec) or in the case
1132 * that the server is misbehaving (or there was an error) before we're
1133 * done sending everything over the wire.
1134 */
1135 mutex_lock(&cmd->lock);
1136 clear_bit(NBD_CMD_REQUEUED, &cmd->flags);
1137
1138 /* We can be called directly from the user space process, which means we
1139 * could possibly have signals pending so our sendmsg will fail. In
1140 * this case we need to return that we are busy, otherwise error out as
1141 * appropriate.
1142 */
1143 ret = nbd_handle_cmd(cmd, hctx->queue_num);
1144 mutex_unlock(&cmd->lock);
1145
1146 return ret;
1147 }
1148
1149 static struct socket *nbd_get_socket(struct nbd_device *nbd, unsigned long fd,
1150 int *err)
1151 {
1152 struct socket *sock;
1153
1154 *err = 0;
1155 sock = sockfd_lookup(fd, err);
1156 if (!sock)
1157 return NULL;
1158
1159 if (sock->ops->shutdown == sock_no_shutdown) {
1160 dev_err(disk_to_dev(nbd->disk), "Unsupported socket: shutdown callout must be supported.\n");
1161 *err = -EINVAL;
1162 sockfd_put(sock);
1163 return NULL;
1164 }
1165
1166 return sock;
1167 }
1168
1169 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
1170 bool netlink)
1171 {
1172 struct nbd_config *config = nbd->config;
1173 struct socket *sock;
1174 struct nbd_sock **socks;
1175 struct nbd_sock *nsock;
1176 int err;
1177
1178 /* Arg will be cast to int, check it to avoid overflow */
1179 if (arg > INT_MAX)
1180 return -EINVAL;
1181 sock = nbd_get_socket(nbd, arg, &err);
1182 if (!sock)
1183 return err;
1184
1185 /*
1186 * We need to make sure we don't get any errant requests while we're
1187 * reallocating the ->socks array.
1188 */
1189 blk_mq_freeze_queue(nbd->disk->queue);
1190
1191 if (!netlink && !nbd->task_setup &&
1192 !test_bit(NBD_RT_BOUND, &config->runtime_flags))
1193 nbd->task_setup = current;
1194
1195 if (!netlink &&
1196 (nbd->task_setup != current ||
1197 test_bit(NBD_RT_BOUND, &config->runtime_flags))) {
1198 dev_err(disk_to_dev(nbd->disk),
1199 "Device being setup by another task");
1200 err = -EBUSY;
1201 goto put_socket;
1202 }
1203
1204 nsock = kzalloc(sizeof(*nsock), GFP_KERNEL);
1205 if (!nsock) {
1206 err = -ENOMEM;
1207 goto put_socket;
1208 }
1209
1210 socks = krealloc(config->socks, (config->num_connections + 1) *
1211 sizeof(struct nbd_sock *), GFP_KERNEL);
1212 if (!socks) {
1213 kfree(nsock);
1214 err = -ENOMEM;
1215 goto put_socket;
1216 }
1217
1218 config->socks = socks;
1219
1220 nsock->fallback_index = -1;
1221 nsock->dead = false;
1222 mutex_init(&nsock->tx_lock);
1223 nsock->sock = sock;
1224 nsock->pending = NULL;
1225 nsock->sent = 0;
1226 nsock->cookie = 0;
1227 socks[config->num_connections++] = nsock;
1228 atomic_inc(&config->live_connections);
1229 blk_mq_unfreeze_queue(nbd->disk->queue);
1230
1231 return 0;
1232
1233 put_socket:
1234 blk_mq_unfreeze_queue(nbd->disk->queue);
1235 sockfd_put(sock);
1236 return err;
1237 }
1238
1239 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
1240 {
1241 struct nbd_config *config = nbd->config;
1242 struct socket *sock, *old;
1243 struct recv_thread_args *args;
1244 int i;
1245 int err;
1246
1247 sock = nbd_get_socket(nbd, arg, &err);
1248 if (!sock)
1249 return err;
1250
1251 args = kzalloc(sizeof(*args), GFP_KERNEL);
1252 if (!args) {
1253 sockfd_put(sock);
1254 return -ENOMEM;
1255 }
1256
1257 for (i = 0; i < config->num_connections; i++) {
1258 struct nbd_sock *nsock = config->socks[i];
1259
1260 if (!nsock->dead)
1261 continue;
1262
1263 mutex_lock(&nsock->tx_lock);
1264 if (!nsock->dead) {
1265 mutex_unlock(&nsock->tx_lock);
1266 continue;
1267 }
1268 sk_set_memalloc(sock->sk);
1269 if (nbd->tag_set.timeout)
1270 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
1271 atomic_inc(&config->recv_threads);
1272 refcount_inc(&nbd->config_refs);
1273 old = nsock->sock;
1274 nsock->fallback_index = -1;
1275 nsock->sock = sock;
1276 nsock->dead = false;
1277 INIT_WORK(&args->work, recv_work);
1278 args->index = i;
1279 args->nbd = nbd;
1280 args->nsock = nsock;
1281 nsock->cookie++;
1282 mutex_unlock(&nsock->tx_lock);
1283 sockfd_put(old);
1284
1285 clear_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
1286
1287 /* We take the tx_mutex in an error path in the recv_work, so we
1288 * need to queue_work outside of the tx_mutex.
1289 */
1290 queue_work(nbd->recv_workq, &args->work);
1291
1292 atomic_inc(&config->live_connections);
1293 wake_up(&config->conn_wait);
1294 return 0;
1295 }
1296 sockfd_put(sock);
1297 kfree(args);
1298 return -ENOSPC;
1299 }
1300
1301 static void nbd_bdev_reset(struct nbd_device *nbd)
1302 {
1303 if (disk_openers(nbd->disk) > 1)
1304 return;
1305 set_capacity(nbd->disk, 0);
1306 }
1307
1308 static void nbd_parse_flags(struct nbd_device *nbd)
1309 {
1310 if (nbd->config->flags & NBD_FLAG_READ_ONLY)
1311 set_disk_ro(nbd->disk, true);
1312 else
1313 set_disk_ro(nbd->disk, false);
1314 }
1315
1316 static void send_disconnects(struct nbd_device *nbd)
1317 {
1318 struct nbd_config *config = nbd->config;
1319 struct nbd_request request = {
1320 .magic = htonl(NBD_REQUEST_MAGIC),
1321 .type = htonl(NBD_CMD_DISC),
1322 };
1323 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
1324 struct iov_iter from;
1325 int i, ret;
1326
1327 for (i = 0; i < config->num_connections; i++) {
1328 struct nbd_sock *nsock = config->socks[i];
1329
1330 iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
1331 mutex_lock(&nsock->tx_lock);
1332 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
1333 if (ret < 0)
1334 dev_err(disk_to_dev(nbd->disk),
1335 "Send disconnect failed %d\n", ret);
1336 mutex_unlock(&nsock->tx_lock);
1337 }
1338 }
1339
1340 static int nbd_disconnect(struct nbd_device *nbd)
1341 {
1342 struct nbd_config *config = nbd->config;
1343
1344 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
1345 set_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags);
1346 set_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags);
1347 send_disconnects(nbd);
1348 return 0;
1349 }
1350
1351 static void nbd_clear_sock(struct nbd_device *nbd)
1352 {
1353 sock_shutdown(nbd);
1354 nbd_clear_que(nbd);
1355 nbd->task_setup = NULL;
1356 }
1357
1358 static void nbd_config_put(struct nbd_device *nbd)
1359 {
1360 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1361 &nbd->config_lock)) {
1362 struct nbd_config *config = nbd->config;
1363 nbd_dev_dbg_close(nbd);
1364 invalidate_disk(nbd->disk);
1365 if (nbd->config->bytesize)
1366 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
1367 if (test_and_clear_bit(NBD_RT_HAS_PID_FILE,
1368 &config->runtime_flags))
1369 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1370 nbd->pid = 0;
1371 if (test_and_clear_bit(NBD_RT_HAS_BACKEND_FILE,
1372 &config->runtime_flags)) {
1373 device_remove_file(disk_to_dev(nbd->disk), &backend_attr);
1374 kfree(nbd->backend);
1375 nbd->backend = NULL;
1376 }
1377 nbd_clear_sock(nbd);
1378 if (config->num_connections) {
1379 int i;
1380 for (i = 0; i < config->num_connections; i++) {
1381 sockfd_put(config->socks[i]->sock);
1382 kfree(config->socks[i]);
1383 }
1384 kfree(config->socks);
1385 }
1386 kfree(nbd->config);
1387 nbd->config = NULL;
1388
1389 nbd->tag_set.timeout = 0;
1390
1391 mutex_unlock(&nbd->config_lock);
1392 nbd_put(nbd);
1393 module_put(THIS_MODULE);
1394 }
1395 }
1396
1397 static int nbd_start_device(struct nbd_device *nbd)
1398 {
1399 struct nbd_config *config = nbd->config;
1400 int num_connections = config->num_connections;
1401 int error = 0, i;
1402
1403 if (nbd->pid)
1404 return -EBUSY;
1405 if (!config->socks)
1406 return -EINVAL;
1407 if (num_connections > 1 &&
1408 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1409 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1410 return -EINVAL;
1411 }
1412
1413 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1414 nbd->pid = task_pid_nr(current);
1415
1416 nbd_parse_flags(nbd);
1417
1418 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1419 if (error) {
1420 dev_err(disk_to_dev(nbd->disk), "device_create_file failed for pid!\n");
1421 return error;
1422 }
1423 set_bit(NBD_RT_HAS_PID_FILE, &config->runtime_flags);
1424
1425 nbd_dev_dbg_init(nbd);
1426 for (i = 0; i < num_connections; i++) {
1427 struct recv_thread_args *args;
1428
1429 args = kzalloc(sizeof(*args), GFP_KERNEL);
1430 if (!args) {
1431 sock_shutdown(nbd);
1432 /*
1433 * If num_connections is m (2 < m),
1434 * and NO.1 ~ NO.n(1 < n < m) kzallocs are successful.
1435 * But NO.(n + 1) failed. We still have n recv threads.
1436 * So, add flush_workqueue here to prevent recv threads
1437 * dropping the last config_refs and trying to destroy
1438 * the workqueue from inside the workqueue.
1439 */
1440 if (i)
1441 flush_workqueue(nbd->recv_workq);
1442 return -ENOMEM;
1443 }
1444 sk_set_memalloc(config->socks[i]->sock->sk);
1445 if (nbd->tag_set.timeout)
1446 config->socks[i]->sock->sk->sk_sndtimeo =
1447 nbd->tag_set.timeout;
1448 atomic_inc(&config->recv_threads);
1449 refcount_inc(&nbd->config_refs);
1450 INIT_WORK(&args->work, recv_work);
1451 args->nbd = nbd;
1452 args->nsock = config->socks[i];
1453 args->index = i;
1454 queue_work(nbd->recv_workq, &args->work);
1455 }
1456 return nbd_set_size(nbd, config->bytesize, nbd_blksize(config));
1457 }
1458
1459 static int nbd_start_device_ioctl(struct nbd_device *nbd)
1460 {
1461 struct nbd_config *config = nbd->config;
1462 int ret;
1463
1464 ret = nbd_start_device(nbd);
1465 if (ret)
1466 return ret;
1467
1468 if (max_part)
1469 set_bit(GD_NEED_PART_SCAN, &nbd->disk->state);
1470 mutex_unlock(&nbd->config_lock);
1471 ret = wait_event_interruptible(config->recv_wq,
1472 atomic_read(&config->recv_threads) == 0);
1473 if (ret) {
1474 sock_shutdown(nbd);
1475 nbd_clear_que(nbd);
1476 }
1477
1478 flush_workqueue(nbd->recv_workq);
1479 mutex_lock(&nbd->config_lock);
1480 nbd_bdev_reset(nbd);
1481 /* user requested, ignore socket errors */
1482 if (test_bit(NBD_RT_DISCONNECT_REQUESTED, &config->runtime_flags))
1483 ret = 0;
1484 if (test_bit(NBD_RT_TIMEDOUT, &config->runtime_flags))
1485 ret = -ETIMEDOUT;
1486 return ret;
1487 }
1488
1489 static void nbd_clear_sock_ioctl(struct nbd_device *nbd)
1490 {
1491 nbd_clear_sock(nbd);
1492 disk_force_media_change(nbd->disk);
1493 nbd_bdev_reset(nbd);
1494 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
1495 &nbd->config->runtime_flags))
1496 nbd_config_put(nbd);
1497 }
1498
1499 static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
1500 {
1501 nbd->tag_set.timeout = timeout * HZ;
1502 if (timeout)
1503 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1504 else
1505 blk_queue_rq_timeout(nbd->disk->queue, 30 * HZ);
1506 }
1507
1508 /* Must be called with config_lock held */
1509 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1510 unsigned int cmd, unsigned long arg)
1511 {
1512 struct nbd_config *config = nbd->config;
1513 loff_t bytesize;
1514
1515 switch (cmd) {
1516 case NBD_DISCONNECT:
1517 return nbd_disconnect(nbd);
1518 case NBD_CLEAR_SOCK:
1519 nbd_clear_sock_ioctl(nbd);
1520 return 0;
1521 case NBD_SET_SOCK:
1522 return nbd_add_socket(nbd, arg, false);
1523 case NBD_SET_BLKSIZE:
1524 return nbd_set_size(nbd, config->bytesize, arg);
1525 case NBD_SET_SIZE:
1526 return nbd_set_size(nbd, arg, nbd_blksize(config));
1527 case NBD_SET_SIZE_BLOCKS:
1528 if (check_shl_overflow(arg, config->blksize_bits, &bytesize))
1529 return -EINVAL;
1530 return nbd_set_size(nbd, bytesize, nbd_blksize(config));
1531 case NBD_SET_TIMEOUT:
1532 nbd_set_cmd_timeout(nbd, arg);
1533 return 0;
1534
1535 case NBD_SET_FLAGS:
1536 config->flags = arg;
1537 return 0;
1538 case NBD_DO_IT:
1539 return nbd_start_device_ioctl(nbd);
1540 case NBD_CLEAR_QUE:
1541 /*
1542 * This is for compatibility only. The queue is always cleared
1543 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1544 */
1545 return 0;
1546 case NBD_PRINT_DEBUG:
1547 /*
1548 * For compatibility only, we no longer keep a list of
1549 * outstanding requests.
1550 */
1551 return 0;
1552 }
1553 return -ENOTTY;
1554 }
1555
1556 static int nbd_ioctl(struct block_device *bdev, blk_mode_t mode,
1557 unsigned int cmd, unsigned long arg)
1558 {
1559 struct nbd_device *nbd = bdev->bd_disk->private_data;
1560 struct nbd_config *config = nbd->config;
1561 int error = -EINVAL;
1562
1563 if (!capable(CAP_SYS_ADMIN))
1564 return -EPERM;
1565
1566 /* The block layer will pass back some non-nbd ioctls in case we have
1567 * special handling for them, but we don't so just return an error.
1568 */
1569 if (_IOC_TYPE(cmd) != 0xab)
1570 return -EINVAL;
1571
1572 mutex_lock(&nbd->config_lock);
1573
1574 /* Don't allow ioctl operations on a nbd device that was created with
1575 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1576 */
1577 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
1578 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1579 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1580 else
1581 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1582 mutex_unlock(&nbd->config_lock);
1583 return error;
1584 }
1585
1586 static int nbd_alloc_and_init_config(struct nbd_device *nbd)
1587 {
1588 struct nbd_config *config;
1589
1590 if (WARN_ON(nbd->config))
1591 return -EINVAL;
1592
1593 if (!try_module_get(THIS_MODULE))
1594 return -ENODEV;
1595
1596 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1597 if (!config) {
1598 module_put(THIS_MODULE);
1599 return -ENOMEM;
1600 }
1601
1602 atomic_set(&config->recv_threads, 0);
1603 init_waitqueue_head(&config->recv_wq);
1604 init_waitqueue_head(&config->conn_wait);
1605 config->blksize_bits = NBD_DEF_BLKSIZE_BITS;
1606 atomic_set(&config->live_connections, 0);
1607
1608 nbd->config = config;
1609 /*
1610 * Order refcount_set(&nbd->config_refs, 1) and nbd->config assignment,
1611 * its pair is the barrier in nbd_get_config_unlocked().
1612 * So nbd_get_config_unlocked() won't see nbd->config as null after
1613 * refcount_inc_not_zero() succeed.
1614 */
1615 smp_mb__before_atomic();
1616 refcount_set(&nbd->config_refs, 1);
1617
1618 return 0;
1619 }
1620
1621 static int nbd_open(struct gendisk *disk, blk_mode_t mode)
1622 {
1623 struct nbd_device *nbd;
1624 struct nbd_config *config;
1625 int ret = 0;
1626
1627 mutex_lock(&nbd_index_mutex);
1628 nbd = disk->private_data;
1629 if (!nbd) {
1630 ret = -ENXIO;
1631 goto out;
1632 }
1633 if (!refcount_inc_not_zero(&nbd->refs)) {
1634 ret = -ENXIO;
1635 goto out;
1636 }
1637
1638 config = nbd_get_config_unlocked(nbd);
1639 if (!config) {
1640 mutex_lock(&nbd->config_lock);
1641 if (refcount_inc_not_zero(&nbd->config_refs)) {
1642 mutex_unlock(&nbd->config_lock);
1643 goto out;
1644 }
1645 ret = nbd_alloc_and_init_config(nbd);
1646 if (ret) {
1647 mutex_unlock(&nbd->config_lock);
1648 goto out;
1649 }
1650
1651 refcount_inc(&nbd->refs);
1652 mutex_unlock(&nbd->config_lock);
1653 if (max_part)
1654 set_bit(GD_NEED_PART_SCAN, &disk->state);
1655 } else if (nbd_disconnected(config)) {
1656 if (max_part)
1657 set_bit(GD_NEED_PART_SCAN, &disk->state);
1658 }
1659 out:
1660 mutex_unlock(&nbd_index_mutex);
1661 return ret;
1662 }
1663
1664 static void nbd_release(struct gendisk *disk)
1665 {
1666 struct nbd_device *nbd = disk->private_data;
1667
1668 if (test_bit(NBD_RT_DISCONNECT_ON_CLOSE, &nbd->config->runtime_flags) &&
1669 disk_openers(disk) == 0)
1670 nbd_disconnect_and_put(nbd);
1671
1672 nbd_config_put(nbd);
1673 nbd_put(nbd);
1674 }
1675
1676 static void nbd_free_disk(struct gendisk *disk)
1677 {
1678 struct nbd_device *nbd = disk->private_data;
1679
1680 kfree(nbd);
1681 }
1682
1683 static const struct block_device_operations nbd_fops =
1684 {
1685 .owner = THIS_MODULE,
1686 .open = nbd_open,
1687 .release = nbd_release,
1688 .ioctl = nbd_ioctl,
1689 .compat_ioctl = nbd_ioctl,
1690 .free_disk = nbd_free_disk,
1691 };
1692
1693 #if IS_ENABLED(CONFIG_DEBUG_FS)
1694
1695 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1696 {
1697 struct nbd_device *nbd = s->private;
1698
1699 if (nbd->pid)
1700 seq_printf(s, "recv: %d\n", nbd->pid);
1701
1702 return 0;
1703 }
1704
1705 DEFINE_SHOW_ATTRIBUTE(nbd_dbg_tasks);
1706
1707 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1708 {
1709 struct nbd_device *nbd = s->private;
1710 u32 flags = nbd->config->flags;
1711
1712 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1713
1714 seq_puts(s, "Known flags:\n");
1715
1716 if (flags & NBD_FLAG_HAS_FLAGS)
1717 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1718 if (flags & NBD_FLAG_READ_ONLY)
1719 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1720 if (flags & NBD_FLAG_SEND_FLUSH)
1721 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1722 if (flags & NBD_FLAG_SEND_FUA)
1723 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1724 if (flags & NBD_FLAG_SEND_TRIM)
1725 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1726 if (flags & NBD_FLAG_SEND_WRITE_ZEROES)
1727 seq_puts(s, "NBD_FLAG_SEND_WRITE_ZEROES\n");
1728 if (flags & NBD_FLAG_ROTATIONAL)
1729 seq_puts(s, "NBD_FLAG_ROTATIONAL\n");
1730
1731 return 0;
1732 }
1733
1734 DEFINE_SHOW_ATTRIBUTE(nbd_dbg_flags);
1735
1736 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1737 {
1738 struct dentry *dir;
1739 struct nbd_config *config = nbd->config;
1740
1741 if (!nbd_dbg_dir)
1742 return -EIO;
1743
1744 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1745 if (IS_ERR(dir)) {
1746 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1747 nbd_name(nbd));
1748 return -EIO;
1749 }
1750 config->dbg_dir = dir;
1751
1752 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_fops);
1753 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1754 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1755 debugfs_create_u32("blocksize_bits", 0444, dir, &config->blksize_bits);
1756 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_fops);
1757
1758 return 0;
1759 }
1760
1761 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1762 {
1763 debugfs_remove_recursive(nbd->config->dbg_dir);
1764 }
1765
1766 static int nbd_dbg_init(void)
1767 {
1768 struct dentry *dbg_dir;
1769
1770 dbg_dir = debugfs_create_dir("nbd", NULL);
1771 if (IS_ERR(dbg_dir))
1772 return -EIO;
1773
1774 nbd_dbg_dir = dbg_dir;
1775
1776 return 0;
1777 }
1778
1779 static void nbd_dbg_close(void)
1780 {
1781 debugfs_remove_recursive(nbd_dbg_dir);
1782 }
1783
1784 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1785
1786 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1787 {
1788 return 0;
1789 }
1790
1791 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1792 {
1793 }
1794
1795 static int nbd_dbg_init(void)
1796 {
1797 return 0;
1798 }
1799
1800 static void nbd_dbg_close(void)
1801 {
1802 }
1803
1804 #endif
1805
1806 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1807 unsigned int hctx_idx, unsigned int numa_node)
1808 {
1809 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1810 cmd->nbd = set->driver_data;
1811 cmd->flags = 0;
1812 mutex_init(&cmd->lock);
1813 return 0;
1814 }
1815
1816 static const struct blk_mq_ops nbd_mq_ops = {
1817 .queue_rq = nbd_queue_rq,
1818 .complete = nbd_complete_rq,
1819 .init_request = nbd_init_request,
1820 .timeout = nbd_xmit_timeout,
1821 };
1822
1823 static struct nbd_device *nbd_dev_add(int index, unsigned int refs)
1824 {
1825 struct queue_limits lim = {
1826 .max_hw_sectors = 65536,
1827 .io_opt = 256 << SECTOR_SHIFT,
1828 .max_segments = USHRT_MAX,
1829 .max_segment_size = UINT_MAX,
1830 };
1831 struct nbd_device *nbd;
1832 struct gendisk *disk;
1833 int err = -ENOMEM;
1834
1835 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1836 if (!nbd)
1837 goto out;
1838
1839 nbd->tag_set.ops = &nbd_mq_ops;
1840 nbd->tag_set.nr_hw_queues = 1;
1841 nbd->tag_set.queue_depth = 128;
1842 nbd->tag_set.numa_node = NUMA_NO_NODE;
1843 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1844 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1845 BLK_MQ_F_BLOCKING;
1846 nbd->tag_set.driver_data = nbd;
1847 INIT_WORK(&nbd->remove_work, nbd_dev_remove_work);
1848 nbd->backend = NULL;
1849
1850 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1851 if (err)
1852 goto out_free_nbd;
1853
1854 mutex_lock(&nbd_index_mutex);
1855 if (index >= 0) {
1856 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1857 GFP_KERNEL);
1858 if (err == -ENOSPC)
1859 err = -EEXIST;
1860 } else {
1861 err = idr_alloc(&nbd_index_idr, nbd, 0,
1862 (MINORMASK >> part_shift) + 1, GFP_KERNEL);
1863 if (err >= 0)
1864 index = err;
1865 }
1866 nbd->index = index;
1867 mutex_unlock(&nbd_index_mutex);
1868 if (err < 0)
1869 goto out_free_tags;
1870
1871 disk = blk_mq_alloc_disk(&nbd->tag_set, &lim, NULL);
1872 if (IS_ERR(disk)) {
1873 err = PTR_ERR(disk);
1874 goto out_free_idr;
1875 }
1876 nbd->disk = disk;
1877
1878 nbd->recv_workq = alloc_workqueue("nbd%d-recv",
1879 WQ_MEM_RECLAIM | WQ_HIGHPRI |
1880 WQ_UNBOUND, 0, nbd->index);
1881 if (!nbd->recv_workq) {
1882 dev_err(disk_to_dev(nbd->disk), "Could not allocate knbd recv work queue.\n");
1883 err = -ENOMEM;
1884 goto out_err_disk;
1885 }
1886
1887 mutex_init(&nbd->config_lock);
1888 refcount_set(&nbd->config_refs, 0);
1889 /*
1890 * Start out with a zero references to keep other threads from using
1891 * this device until it is fully initialized.
1892 */
1893 refcount_set(&nbd->refs, 0);
1894 INIT_LIST_HEAD(&nbd->list);
1895 disk->major = NBD_MAJOR;
1896 disk->first_minor = index << part_shift;
1897 disk->minors = 1 << part_shift;
1898 disk->fops = &nbd_fops;
1899 disk->private_data = nbd;
1900 sprintf(disk->disk_name, "nbd%d", index);
1901 err = add_disk(disk);
1902 if (err)
1903 goto out_free_work;
1904
1905 /*
1906 * Now publish the device.
1907 */
1908 refcount_set(&nbd->refs, refs);
1909 nbd_total_devices++;
1910 return nbd;
1911
1912 out_free_work:
1913 destroy_workqueue(nbd->recv_workq);
1914 out_err_disk:
1915 put_disk(disk);
1916 out_free_idr:
1917 mutex_lock(&nbd_index_mutex);
1918 idr_remove(&nbd_index_idr, index);
1919 mutex_unlock(&nbd_index_mutex);
1920 out_free_tags:
1921 blk_mq_free_tag_set(&nbd->tag_set);
1922 out_free_nbd:
1923 kfree(nbd);
1924 out:
1925 return ERR_PTR(err);
1926 }
1927
1928 static struct nbd_device *nbd_find_get_unused(void)
1929 {
1930 struct nbd_device *nbd;
1931 int id;
1932
1933 lockdep_assert_held(&nbd_index_mutex);
1934
1935 idr_for_each_entry(&nbd_index_idr, nbd, id) {
1936 if (refcount_read(&nbd->config_refs) ||
1937 test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags))
1938 continue;
1939 if (refcount_inc_not_zero(&nbd->refs))
1940 return nbd;
1941 }
1942
1943 return NULL;
1944 }
1945
1946 /* Netlink interface. */
1947 static const struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1948 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1949 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1950 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1951 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1952 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1953 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1954 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1955 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1956 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1957 [NBD_ATTR_BACKEND_IDENTIFIER] = { .type = NLA_STRING},
1958 };
1959
1960 static const struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1961 [NBD_SOCK_FD] = { .type = NLA_U32 },
1962 };
1963
1964 /* We don't use this right now since we don't parse the incoming list, but we
1965 * still want it here so userspace knows what to expect.
1966 */
1967 static const struct nla_policy __attribute__((unused))
1968 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1969 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1970 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1971 };
1972
1973 static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
1974 {
1975 struct nbd_config *config = nbd->config;
1976 u64 bsize = nbd_blksize(config);
1977 u64 bytes = config->bytesize;
1978
1979 if (info->attrs[NBD_ATTR_SIZE_BYTES])
1980 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1981
1982 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES])
1983 bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1984
1985 if (bytes != config->bytesize || bsize != nbd_blksize(config))
1986 return nbd_set_size(nbd, bytes, bsize);
1987 return 0;
1988 }
1989
1990 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1991 {
1992 struct nbd_device *nbd;
1993 struct nbd_config *config;
1994 int index = -1;
1995 int ret;
1996 bool put_dev = false;
1997
1998 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1999 return -EPERM;
2000
2001 if (info->attrs[NBD_ATTR_INDEX]) {
2002 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2003
2004 /*
2005 * Too big first_minor can cause duplicate creation of
2006 * sysfs files/links, since index << part_shift might overflow, or
2007 * MKDEV() expect that the max bits of first_minor is 20.
2008 */
2009 if (index < 0 || index > MINORMASK >> part_shift) {
2010 pr_err("illegal input index %d\n", index);
2011 return -EINVAL;
2012 }
2013 }
2014 if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_SOCKETS)) {
2015 pr_err("must specify at least one socket\n");
2016 return -EINVAL;
2017 }
2018 if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_SIZE_BYTES)) {
2019 pr_err("must specify a size in bytes for the device\n");
2020 return -EINVAL;
2021 }
2022 again:
2023 mutex_lock(&nbd_index_mutex);
2024 if (index == -1) {
2025 nbd = nbd_find_get_unused();
2026 } else {
2027 nbd = idr_find(&nbd_index_idr, index);
2028 if (nbd) {
2029 if ((test_bit(NBD_DESTROY_ON_DISCONNECT, &nbd->flags) &&
2030 test_bit(NBD_DISCONNECT_REQUESTED, &nbd->flags)) ||
2031 !refcount_inc_not_zero(&nbd->refs)) {
2032 mutex_unlock(&nbd_index_mutex);
2033 pr_err("device at index %d is going down\n",
2034 index);
2035 return -EINVAL;
2036 }
2037 }
2038 }
2039 mutex_unlock(&nbd_index_mutex);
2040
2041 if (!nbd) {
2042 nbd = nbd_dev_add(index, 2);
2043 if (IS_ERR(nbd)) {
2044 pr_err("failed to add new device\n");
2045 return PTR_ERR(nbd);
2046 }
2047 }
2048
2049 mutex_lock(&nbd->config_lock);
2050 if (refcount_read(&nbd->config_refs)) {
2051 mutex_unlock(&nbd->config_lock);
2052 nbd_put(nbd);
2053 if (index == -1)
2054 goto again;
2055 pr_err("nbd%d already in use\n", index);
2056 return -EBUSY;
2057 }
2058
2059 ret = nbd_alloc_and_init_config(nbd);
2060 if (ret) {
2061 mutex_unlock(&nbd->config_lock);
2062 nbd_put(nbd);
2063 pr_err("couldn't allocate config\n");
2064 return ret;
2065 }
2066
2067 config = nbd->config;
2068 set_bit(NBD_RT_BOUND, &config->runtime_flags);
2069 ret = nbd_genl_size_set(info, nbd);
2070 if (ret)
2071 goto out;
2072
2073 if (info->attrs[NBD_ATTR_TIMEOUT])
2074 nbd_set_cmd_timeout(nbd,
2075 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2076 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2077 config->dead_conn_timeout =
2078 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2079 config->dead_conn_timeout *= HZ;
2080 }
2081 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
2082 config->flags =
2083 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
2084 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2085 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2086 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2087 /*
2088 * We have 1 ref to keep the device around, and then 1
2089 * ref for our current operation here, which will be
2090 * inherited by the config. If we already have
2091 * DESTROY_ON_DISCONNECT set then we know we don't have
2092 * that extra ref already held so we don't need the
2093 * put_dev.
2094 */
2095 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
2096 &nbd->flags))
2097 put_dev = true;
2098 } else {
2099 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
2100 &nbd->flags))
2101 refcount_inc(&nbd->refs);
2102 }
2103 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2104 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2105 &config->runtime_flags);
2106 }
2107 }
2108
2109 if (info->attrs[NBD_ATTR_SOCKETS]) {
2110 struct nlattr *attr;
2111 int rem, fd;
2112
2113 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2114 rem) {
2115 struct nlattr *socks[NBD_SOCK_MAX+1];
2116
2117 if (nla_type(attr) != NBD_SOCK_ITEM) {
2118 pr_err("socks must be embedded in a SOCK_ITEM attr\n");
2119 ret = -EINVAL;
2120 goto out;
2121 }
2122 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2123 attr,
2124 nbd_sock_policy,
2125 info->extack);
2126 if (ret != 0) {
2127 pr_err("error processing sock list\n");
2128 ret = -EINVAL;
2129 goto out;
2130 }
2131 if (!socks[NBD_SOCK_FD])
2132 continue;
2133 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2134 ret = nbd_add_socket(nbd, fd, true);
2135 if (ret)
2136 goto out;
2137 }
2138 }
2139 ret = nbd_start_device(nbd);
2140 if (ret)
2141 goto out;
2142 if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
2143 nbd->backend = nla_strdup(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
2144 GFP_KERNEL);
2145 if (!nbd->backend) {
2146 ret = -ENOMEM;
2147 goto out;
2148 }
2149 }
2150 ret = device_create_file(disk_to_dev(nbd->disk), &backend_attr);
2151 if (ret) {
2152 dev_err(disk_to_dev(nbd->disk),
2153 "device_create_file failed for backend!\n");
2154 goto out;
2155 }
2156 set_bit(NBD_RT_HAS_BACKEND_FILE, &config->runtime_flags);
2157 out:
2158 mutex_unlock(&nbd->config_lock);
2159 if (!ret) {
2160 set_bit(NBD_RT_HAS_CONFIG_REF, &config->runtime_flags);
2161 refcount_inc(&nbd->config_refs);
2162 nbd_connect_reply(info, nbd->index);
2163 }
2164 nbd_config_put(nbd);
2165 if (put_dev)
2166 nbd_put(nbd);
2167 return ret;
2168 }
2169
2170 static void nbd_disconnect_and_put(struct nbd_device *nbd)
2171 {
2172 mutex_lock(&nbd->config_lock);
2173 nbd_disconnect(nbd);
2174 sock_shutdown(nbd);
2175 wake_up(&nbd->config->conn_wait);
2176 /*
2177 * Make sure recv thread has finished, we can safely call nbd_clear_que()
2178 * to cancel the inflight I/Os.
2179 */
2180 flush_workqueue(nbd->recv_workq);
2181 nbd_clear_que(nbd);
2182 nbd->task_setup = NULL;
2183 mutex_unlock(&nbd->config_lock);
2184
2185 if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF,
2186 &nbd->config->runtime_flags))
2187 nbd_config_put(nbd);
2188 }
2189
2190 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
2191 {
2192 struct nbd_device *nbd;
2193 int index;
2194
2195 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2196 return -EPERM;
2197
2198 if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_INDEX)) {
2199 pr_err("must specify an index to disconnect\n");
2200 return -EINVAL;
2201 }
2202 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2203 mutex_lock(&nbd_index_mutex);
2204 nbd = idr_find(&nbd_index_idr, index);
2205 if (!nbd) {
2206 mutex_unlock(&nbd_index_mutex);
2207 pr_err("couldn't find device at index %d\n", index);
2208 return -EINVAL;
2209 }
2210 if (!refcount_inc_not_zero(&nbd->refs)) {
2211 mutex_unlock(&nbd_index_mutex);
2212 pr_err("device at index %d is going down\n", index);
2213 return -EINVAL;
2214 }
2215 mutex_unlock(&nbd_index_mutex);
2216 if (!refcount_inc_not_zero(&nbd->config_refs))
2217 goto put_nbd;
2218 nbd_disconnect_and_put(nbd);
2219 nbd_config_put(nbd);
2220 put_nbd:
2221 nbd_put(nbd);
2222 return 0;
2223 }
2224
2225 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
2226 {
2227 struct nbd_device *nbd = NULL;
2228 struct nbd_config *config;
2229 int index;
2230 int ret = 0;
2231 bool put_dev = false;
2232
2233 if (!netlink_capable(skb, CAP_SYS_ADMIN))
2234 return -EPERM;
2235
2236 if (GENL_REQ_ATTR_CHECK(info, NBD_ATTR_INDEX)) {
2237 pr_err("must specify a device to reconfigure\n");
2238 return -EINVAL;
2239 }
2240 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2241 mutex_lock(&nbd_index_mutex);
2242 nbd = idr_find(&nbd_index_idr, index);
2243 if (!nbd) {
2244 mutex_unlock(&nbd_index_mutex);
2245 pr_err("couldn't find a device at index %d\n", index);
2246 return -EINVAL;
2247 }
2248 if (nbd->backend) {
2249 if (info->attrs[NBD_ATTR_BACKEND_IDENTIFIER]) {
2250 if (nla_strcmp(info->attrs[NBD_ATTR_BACKEND_IDENTIFIER],
2251 nbd->backend)) {
2252 mutex_unlock(&nbd_index_mutex);
2253 dev_err(nbd_to_dev(nbd),
2254 "backend image doesn't match with %s\n",
2255 nbd->backend);
2256 return -EINVAL;
2257 }
2258 } else {
2259 mutex_unlock(&nbd_index_mutex);
2260 dev_err(nbd_to_dev(nbd), "must specify backend\n");
2261 return -EINVAL;
2262 }
2263 }
2264 if (!refcount_inc_not_zero(&nbd->refs)) {
2265 mutex_unlock(&nbd_index_mutex);
2266 pr_err("device at index %d is going down\n", index);
2267 return -EINVAL;
2268 }
2269 mutex_unlock(&nbd_index_mutex);
2270
2271 config = nbd_get_config_unlocked(nbd);
2272 if (!config) {
2273 dev_err(nbd_to_dev(nbd),
2274 "not configured, cannot reconfigure\n");
2275 nbd_put(nbd);
2276 return -EINVAL;
2277 }
2278
2279 mutex_lock(&nbd->config_lock);
2280 if (!test_bit(NBD_RT_BOUND, &config->runtime_flags) ||
2281 !nbd->pid) {
2282 dev_err(nbd_to_dev(nbd),
2283 "not configured, cannot reconfigure\n");
2284 ret = -EINVAL;
2285 goto out;
2286 }
2287
2288 ret = nbd_genl_size_set(info, nbd);
2289 if (ret)
2290 goto out;
2291
2292 if (info->attrs[NBD_ATTR_TIMEOUT])
2293 nbd_set_cmd_timeout(nbd,
2294 nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]));
2295 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
2296 config->dead_conn_timeout =
2297 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
2298 config->dead_conn_timeout *= HZ;
2299 }
2300 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
2301 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
2302 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
2303 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
2304 &nbd->flags))
2305 put_dev = true;
2306 } else {
2307 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
2308 &nbd->flags))
2309 refcount_inc(&nbd->refs);
2310 }
2311
2312 if (flags & NBD_CFLAG_DISCONNECT_ON_CLOSE) {
2313 set_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2314 &config->runtime_flags);
2315 } else {
2316 clear_bit(NBD_RT_DISCONNECT_ON_CLOSE,
2317 &config->runtime_flags);
2318 }
2319 }
2320
2321 if (info->attrs[NBD_ATTR_SOCKETS]) {
2322 struct nlattr *attr;
2323 int rem, fd;
2324
2325 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
2326 rem) {
2327 struct nlattr *socks[NBD_SOCK_MAX+1];
2328
2329 if (nla_type(attr) != NBD_SOCK_ITEM) {
2330 pr_err("socks must be embedded in a SOCK_ITEM attr\n");
2331 ret = -EINVAL;
2332 goto out;
2333 }
2334 ret = nla_parse_nested_deprecated(socks, NBD_SOCK_MAX,
2335 attr,
2336 nbd_sock_policy,
2337 info->extack);
2338 if (ret != 0) {
2339 pr_err("error processing sock list\n");
2340 ret = -EINVAL;
2341 goto out;
2342 }
2343 if (!socks[NBD_SOCK_FD])
2344 continue;
2345 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
2346 ret = nbd_reconnect_socket(nbd, fd);
2347 if (ret) {
2348 if (ret == -ENOSPC)
2349 ret = 0;
2350 goto out;
2351 }
2352 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
2353 }
2354 }
2355 out:
2356 mutex_unlock(&nbd->config_lock);
2357 nbd_config_put(nbd);
2358 nbd_put(nbd);
2359 if (put_dev)
2360 nbd_put(nbd);
2361 return ret;
2362 }
2363
2364 static const struct genl_small_ops nbd_connect_genl_ops[] = {
2365 {
2366 .cmd = NBD_CMD_CONNECT,
2367 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2368 .doit = nbd_genl_connect,
2369 },
2370 {
2371 .cmd = NBD_CMD_DISCONNECT,
2372 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2373 .doit = nbd_genl_disconnect,
2374 },
2375 {
2376 .cmd = NBD_CMD_RECONFIGURE,
2377 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2378 .doit = nbd_genl_reconfigure,
2379 },
2380 {
2381 .cmd = NBD_CMD_STATUS,
2382 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
2383 .doit = nbd_genl_status,
2384 },
2385 };
2386
2387 static const struct genl_multicast_group nbd_mcast_grps[] = {
2388 { .name = NBD_GENL_MCAST_GROUP_NAME, },
2389 };
2390
2391 static struct genl_family nbd_genl_family __ro_after_init = {
2392 .hdrsize = 0,
2393 .name = NBD_GENL_FAMILY_NAME,
2394 .version = NBD_GENL_VERSION,
2395 .module = THIS_MODULE,
2396 .small_ops = nbd_connect_genl_ops,
2397 .n_small_ops = ARRAY_SIZE(nbd_connect_genl_ops),
2398 .resv_start_op = NBD_CMD_STATUS + 1,
2399 .maxattr = NBD_ATTR_MAX,
2400 .netnsok = 1,
2401 .policy = nbd_attr_policy,
2402 .mcgrps = nbd_mcast_grps,
2403 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
2404 };
2405 MODULE_ALIAS_GENL_FAMILY(NBD_GENL_FAMILY_NAME);
2406
2407 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
2408 {
2409 struct nlattr *dev_opt;
2410 u8 connected = 0;
2411 int ret;
2412
2413 /* This is a little racey, but for status it's ok. The
2414 * reason we don't take a ref here is because we can't
2415 * take a ref in the index == -1 case as we would need
2416 * to put under the nbd_index_mutex, which could
2417 * deadlock if we are configured to remove ourselves
2418 * once we're disconnected.
2419 */
2420 if (refcount_read(&nbd->config_refs))
2421 connected = 1;
2422 dev_opt = nla_nest_start_noflag(reply, NBD_DEVICE_ITEM);
2423 if (!dev_opt)
2424 return -EMSGSIZE;
2425 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
2426 if (ret)
2427 return -EMSGSIZE;
2428 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
2429 connected);
2430 if (ret)
2431 return -EMSGSIZE;
2432 nla_nest_end(reply, dev_opt);
2433 return 0;
2434 }
2435
2436 static int status_cb(int id, void *ptr, void *data)
2437 {
2438 struct nbd_device *nbd = ptr;
2439 return populate_nbd_status(nbd, (struct sk_buff *)data);
2440 }
2441
2442 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
2443 {
2444 struct nlattr *dev_list;
2445 struct sk_buff *reply;
2446 void *reply_head;
2447 size_t msg_size;
2448 int index = -1;
2449 int ret = -ENOMEM;
2450
2451 if (info->attrs[NBD_ATTR_INDEX])
2452 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
2453
2454 mutex_lock(&nbd_index_mutex);
2455
2456 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
2457 nla_attr_size(sizeof(u8)));
2458 msg_size *= (index == -1) ? nbd_total_devices : 1;
2459
2460 reply = genlmsg_new(msg_size, GFP_KERNEL);
2461 if (!reply)
2462 goto out;
2463 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
2464 NBD_CMD_STATUS);
2465 if (!reply_head) {
2466 nlmsg_free(reply);
2467 goto out;
2468 }
2469
2470 dev_list = nla_nest_start_noflag(reply, NBD_ATTR_DEVICE_LIST);
2471 if (!dev_list) {
2472 nlmsg_free(reply);
2473 ret = -EMSGSIZE;
2474 goto out;
2475 }
2476
2477 if (index == -1) {
2478 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
2479 if (ret) {
2480 nlmsg_free(reply);
2481 goto out;
2482 }
2483 } else {
2484 struct nbd_device *nbd;
2485 nbd = idr_find(&nbd_index_idr, index);
2486 if (nbd) {
2487 ret = populate_nbd_status(nbd, reply);
2488 if (ret) {
2489 nlmsg_free(reply);
2490 goto out;
2491 }
2492 }
2493 }
2494 nla_nest_end(reply, dev_list);
2495 genlmsg_end(reply, reply_head);
2496 ret = genlmsg_reply(reply, info);
2497 out:
2498 mutex_unlock(&nbd_index_mutex);
2499 return ret;
2500 }
2501
2502 static void nbd_connect_reply(struct genl_info *info, int index)
2503 {
2504 struct sk_buff *skb;
2505 void *msg_head;
2506 int ret;
2507
2508 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2509 if (!skb)
2510 return;
2511 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
2512 NBD_CMD_CONNECT);
2513 if (!msg_head) {
2514 nlmsg_free(skb);
2515 return;
2516 }
2517 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2518 if (ret) {
2519 nlmsg_free(skb);
2520 return;
2521 }
2522 genlmsg_end(skb, msg_head);
2523 genlmsg_reply(skb, info);
2524 }
2525
2526 static void nbd_mcast_index(int index)
2527 {
2528 struct sk_buff *skb;
2529 void *msg_head;
2530 int ret;
2531
2532 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2533 if (!skb)
2534 return;
2535 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2536 NBD_CMD_LINK_DEAD);
2537 if (!msg_head) {
2538 nlmsg_free(skb);
2539 return;
2540 }
2541 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2542 if (ret) {
2543 nlmsg_free(skb);
2544 return;
2545 }
2546 genlmsg_end(skb, msg_head);
2547 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2548 }
2549
2550 static void nbd_dead_link_work(struct work_struct *work)
2551 {
2552 struct link_dead_args *args = container_of(work, struct link_dead_args,
2553 work);
2554 nbd_mcast_index(args->index);
2555 kfree(args);
2556 }
2557
2558 static int __init nbd_init(void)
2559 {
2560 int i;
2561
2562 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2563
2564 if (max_part < 0) {
2565 pr_err("max_part must be >= 0\n");
2566 return -EINVAL;
2567 }
2568
2569 part_shift = 0;
2570 if (max_part > 0) {
2571 part_shift = fls(max_part);
2572
2573 /*
2574 * Adjust max_part according to part_shift as it is exported
2575 * to user space so that user can know the max number of
2576 * partition kernel should be able to manage.
2577 *
2578 * Note that -1 is required because partition 0 is reserved
2579 * for the whole disk.
2580 */
2581 max_part = (1UL << part_shift) - 1;
2582 }
2583
2584 if ((1UL << part_shift) > DISK_MAX_PARTS)
2585 return -EINVAL;
2586
2587 if (nbds_max > 1UL << (MINORBITS - part_shift))
2588 return -EINVAL;
2589
2590 if (register_blkdev(NBD_MAJOR, "nbd"))
2591 return -EIO;
2592
2593 nbd_del_wq = alloc_workqueue("nbd-del", WQ_UNBOUND, 0);
2594 if (!nbd_del_wq) {
2595 unregister_blkdev(NBD_MAJOR, "nbd");
2596 return -ENOMEM;
2597 }
2598
2599 if (genl_register_family(&nbd_genl_family)) {
2600 destroy_workqueue(nbd_del_wq);
2601 unregister_blkdev(NBD_MAJOR, "nbd");
2602 return -EINVAL;
2603 }
2604 nbd_dbg_init();
2605
2606 for (i = 0; i < nbds_max; i++)
2607 nbd_dev_add(i, 1);
2608 return 0;
2609 }
2610
2611 static int nbd_exit_cb(int id, void *ptr, void *data)
2612 {
2613 struct list_head *list = (struct list_head *)data;
2614 struct nbd_device *nbd = ptr;
2615
2616 /* Skip nbd that is being removed asynchronously */
2617 if (refcount_read(&nbd->refs))
2618 list_add_tail(&nbd->list, list);
2619
2620 return 0;
2621 }
2622
2623 static void __exit nbd_cleanup(void)
2624 {
2625 struct nbd_device *nbd;
2626 LIST_HEAD(del_list);
2627
2628 /*
2629 * Unregister netlink interface prior to waiting
2630 * for the completion of netlink commands.
2631 */
2632 genl_unregister_family(&nbd_genl_family);
2633
2634 nbd_dbg_close();
2635
2636 mutex_lock(&nbd_index_mutex);
2637 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2638 mutex_unlock(&nbd_index_mutex);
2639
2640 while (!list_empty(&del_list)) {
2641 nbd = list_first_entry(&del_list, struct nbd_device, list);
2642 list_del_init(&nbd->list);
2643 if (refcount_read(&nbd->config_refs))
2644 pr_err("possibly leaking nbd_config (ref %d)\n",
2645 refcount_read(&nbd->config_refs));
2646 if (refcount_read(&nbd->refs) != 1)
2647 pr_err("possibly leaking a device\n");
2648 nbd_put(nbd);
2649 }
2650
2651 /* Also wait for nbd_dev_remove_work() completes */
2652 destroy_workqueue(nbd_del_wq);
2653
2654 idr_destroy(&nbd_index_idr);
2655 unregister_blkdev(NBD_MAJOR, "nbd");
2656 }
2657
2658 module_init(nbd_init);
2659 module_exit(nbd_cleanup);
2660
2661 MODULE_DESCRIPTION("Network Block Device");
2662 MODULE_LICENSE("GPL");
2663
2664 module_param(nbds_max, int, 0444);
2665 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2666 module_param(max_part, int, 0444);
2667 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 16)");
Kernel DRM miscellaneous fixes and cross-tree changes