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ASoC: ux500: Restore platform DAI assignments
[mirror_ubuntu-artful-kernel.git] / drivers / block / nbd.c
1 /*
2 * Network block device - make block devices work over TCP
3 *
4 * Note that you can not swap over this thing, yet. Seems to work but
5 * deadlocks sometimes - you can not swap over TCP in general.
6 *
7 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
8 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
9 *
10 * This file is released under GPLv2 or later.
11 *
12 * (part of code stolen from loop.c)
13 */
14
15 #include <linux/major.h>
16
17 #include <linux/blkdev.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/sched.h>
21 #include <linux/sched/mm.h>
22 #include <linux/fs.h>
23 #include <linux/bio.h>
24 #include <linux/stat.h>
25 #include <linux/errno.h>
26 #include <linux/file.h>
27 #include <linux/ioctl.h>
28 #include <linux/mutex.h>
29 #include <linux/compiler.h>
30 #include <linux/err.h>
31 #include <linux/kernel.h>
32 #include <linux/slab.h>
33 #include <net/sock.h>
34 #include <linux/net.h>
35 #include <linux/kthread.h>
36 #include <linux/types.h>
37 #include <linux/debugfs.h>
38 #include <linux/blk-mq.h>
39
40 #include <linux/uaccess.h>
41 #include <asm/types.h>
42
43 #include <linux/nbd.h>
44 #include <linux/nbd-netlink.h>
45 #include <net/genetlink.h>
46
47 static DEFINE_IDR(nbd_index_idr);
48 static DEFINE_MUTEX(nbd_index_mutex);
49 static int nbd_total_devices = 0;
50
51 struct nbd_sock {
52 struct socket *sock;
53 struct mutex tx_lock;
54 struct request *pending;
55 int sent;
56 bool dead;
57 int fallback_index;
58 int cookie;
59 };
60
61 struct recv_thread_args {
62 struct work_struct work;
63 struct nbd_device *nbd;
64 int index;
65 };
66
67 struct link_dead_args {
68 struct work_struct work;
69 int index;
70 };
71
72 #define NBD_TIMEDOUT 0
73 #define NBD_DISCONNECT_REQUESTED 1
74 #define NBD_DISCONNECTED 2
75 #define NBD_HAS_PID_FILE 3
76 #define NBD_HAS_CONFIG_REF 4
77 #define NBD_BOUND 5
78 #define NBD_DESTROY_ON_DISCONNECT 6
79
80 struct nbd_config {
81 u32 flags;
82 unsigned long runtime_flags;
83 u64 dead_conn_timeout;
84
85 struct nbd_sock **socks;
86 int num_connections;
87 atomic_t live_connections;
88 wait_queue_head_t conn_wait;
89
90 atomic_t recv_threads;
91 wait_queue_head_t recv_wq;
92 loff_t blksize;
93 loff_t bytesize;
94 #if IS_ENABLED(CONFIG_DEBUG_FS)
95 struct dentry *dbg_dir;
96 #endif
97 };
98
99 struct nbd_device {
100 struct blk_mq_tag_set tag_set;
101
102 int index;
103 refcount_t config_refs;
104 refcount_t refs;
105 struct nbd_config *config;
106 struct mutex config_lock;
107 struct gendisk *disk;
108
109 struct list_head list;
110 struct task_struct *task_recv;
111 struct task_struct *task_setup;
112 };
113
114 struct nbd_cmd {
115 struct nbd_device *nbd;
116 int index;
117 int cookie;
118 struct completion send_complete;
119 blk_status_t status;
120 };
121
122 #if IS_ENABLED(CONFIG_DEBUG_FS)
123 static struct dentry *nbd_dbg_dir;
124 #endif
125
126 #define nbd_name(nbd) ((nbd)->disk->disk_name)
127
128 #define NBD_MAGIC 0x68797548
129
130 static unsigned int nbds_max = 16;
131 static int max_part;
132 static struct workqueue_struct *recv_workqueue;
133 static int part_shift;
134
135 static int nbd_dev_dbg_init(struct nbd_device *nbd);
136 static void nbd_dev_dbg_close(struct nbd_device *nbd);
137 static void nbd_config_put(struct nbd_device *nbd);
138 static void nbd_connect_reply(struct genl_info *info, int index);
139 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info);
140 static void nbd_dead_link_work(struct work_struct *work);
141
142 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
143 {
144 return disk_to_dev(nbd->disk);
145 }
146
147 static const char *nbdcmd_to_ascii(int cmd)
148 {
149 switch (cmd) {
150 case NBD_CMD_READ: return "read";
151 case NBD_CMD_WRITE: return "write";
152 case NBD_CMD_DISC: return "disconnect";
153 case NBD_CMD_FLUSH: return "flush";
154 case NBD_CMD_TRIM: return "trim/discard";
155 }
156 return "invalid";
157 }
158
159 static ssize_t pid_show(struct device *dev,
160 struct device_attribute *attr, char *buf)
161 {
162 struct gendisk *disk = dev_to_disk(dev);
163 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
164
165 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
166 }
167
168 static struct device_attribute pid_attr = {
169 .attr = { .name = "pid", .mode = S_IRUGO},
170 .show = pid_show,
171 };
172
173 static void nbd_dev_remove(struct nbd_device *nbd)
174 {
175 struct gendisk *disk = nbd->disk;
176 if (disk) {
177 del_gendisk(disk);
178 blk_cleanup_queue(disk->queue);
179 blk_mq_free_tag_set(&nbd->tag_set);
180 disk->private_data = NULL;
181 put_disk(disk);
182 }
183 kfree(nbd);
184 }
185
186 static void nbd_put(struct nbd_device *nbd)
187 {
188 if (refcount_dec_and_mutex_lock(&nbd->refs,
189 &nbd_index_mutex)) {
190 idr_remove(&nbd_index_idr, nbd->index);
191 mutex_unlock(&nbd_index_mutex);
192 nbd_dev_remove(nbd);
193 }
194 }
195
196 static int nbd_disconnected(struct nbd_config *config)
197 {
198 return test_bit(NBD_DISCONNECTED, &config->runtime_flags) ||
199 test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
200 }
201
202 static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
203 int notify)
204 {
205 if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) {
206 struct link_dead_args *args;
207 args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO);
208 if (args) {
209 INIT_WORK(&args->work, nbd_dead_link_work);
210 args->index = nbd->index;
211 queue_work(system_wq, &args->work);
212 }
213 }
214 if (!nsock->dead) {
215 kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
216 atomic_dec(&nbd->config->live_connections);
217 }
218 nsock->dead = true;
219 nsock->pending = NULL;
220 nsock->sent = 0;
221 }
222
223 static void nbd_size_clear(struct nbd_device *nbd)
224 {
225 if (nbd->config->bytesize) {
226 set_capacity(nbd->disk, 0);
227 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
228 }
229 }
230
231 static void nbd_size_update(struct nbd_device *nbd)
232 {
233 struct nbd_config *config = nbd->config;
234 blk_queue_logical_block_size(nbd->disk->queue, config->blksize);
235 blk_queue_physical_block_size(nbd->disk->queue, config->blksize);
236 set_capacity(nbd->disk, config->bytesize >> 9);
237 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
238 }
239
240 static void nbd_size_set(struct nbd_device *nbd, loff_t blocksize,
241 loff_t nr_blocks)
242 {
243 struct nbd_config *config = nbd->config;
244 config->blksize = blocksize;
245 config->bytesize = blocksize * nr_blocks;
246 nbd_size_update(nbd);
247 }
248
249 static void nbd_complete_rq(struct request *req)
250 {
251 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
252
253 dev_dbg(nbd_to_dev(cmd->nbd), "request %p: %s\n", cmd,
254 cmd->status ? "failed" : "done");
255
256 blk_mq_end_request(req, cmd->status);
257 }
258
259 /*
260 * Forcibly shutdown the socket causing all listeners to error
261 */
262 static void sock_shutdown(struct nbd_device *nbd)
263 {
264 struct nbd_config *config = nbd->config;
265 int i;
266
267 if (config->num_connections == 0)
268 return;
269 if (test_and_set_bit(NBD_DISCONNECTED, &config->runtime_flags))
270 return;
271
272 for (i = 0; i < config->num_connections; i++) {
273 struct nbd_sock *nsock = config->socks[i];
274 mutex_lock(&nsock->tx_lock);
275 nbd_mark_nsock_dead(nbd, nsock, 0);
276 mutex_unlock(&nsock->tx_lock);
277 }
278 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
279 }
280
281 static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
282 bool reserved)
283 {
284 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
285 struct nbd_device *nbd = cmd->nbd;
286 struct nbd_config *config;
287
288 if (!refcount_inc_not_zero(&nbd->config_refs)) {
289 cmd->status = BLK_STS_TIMEOUT;
290 return BLK_EH_HANDLED;
291 }
292
293 /* If we are waiting on our dead timer then we could get timeout
294 * callbacks for our request. For this we just want to reset the timer
295 * and let the queue side take care of everything.
296 */
297 if (!completion_done(&cmd->send_complete)) {
298 nbd_config_put(nbd);
299 return BLK_EH_RESET_TIMER;
300 }
301 config = nbd->config;
302
303 if (config->num_connections > 1) {
304 dev_err_ratelimited(nbd_to_dev(nbd),
305 "Connection timed out, retrying\n");
306 /*
307 * Hooray we have more connections, requeue this IO, the submit
308 * path will put it on a real connection.
309 */
310 if (config->socks && config->num_connections > 1) {
311 if (cmd->index < config->num_connections) {
312 struct nbd_sock *nsock =
313 config->socks[cmd->index];
314 mutex_lock(&nsock->tx_lock);
315 /* We can have multiple outstanding requests, so
316 * we don't want to mark the nsock dead if we've
317 * already reconnected with a new socket, so
318 * only mark it dead if its the same socket we
319 * were sent out on.
320 */
321 if (cmd->cookie == nsock->cookie)
322 nbd_mark_nsock_dead(nbd, nsock, 1);
323 mutex_unlock(&nsock->tx_lock);
324 }
325 blk_mq_requeue_request(req, true);
326 nbd_config_put(nbd);
327 return BLK_EH_NOT_HANDLED;
328 }
329 } else {
330 dev_err_ratelimited(nbd_to_dev(nbd),
331 "Connection timed out\n");
332 }
333 set_bit(NBD_TIMEDOUT, &config->runtime_flags);
334 cmd->status = BLK_STS_IOERR;
335 sock_shutdown(nbd);
336 nbd_config_put(nbd);
337
338 return BLK_EH_HANDLED;
339 }
340
341 /*
342 * Send or receive packet.
343 */
344 static int sock_xmit(struct nbd_device *nbd, int index, int send,
345 struct iov_iter *iter, int msg_flags, int *sent)
346 {
347 struct nbd_config *config = nbd->config;
348 struct socket *sock = config->socks[index]->sock;
349 int result;
350 struct msghdr msg;
351 unsigned int noreclaim_flag;
352
353 if (unlikely(!sock)) {
354 dev_err_ratelimited(disk_to_dev(nbd->disk),
355 "Attempted %s on closed socket in sock_xmit\n",
356 (send ? "send" : "recv"));
357 return -EINVAL;
358 }
359
360 msg.msg_iter = *iter;
361
362 noreclaim_flag = memalloc_noreclaim_save();
363 do {
364 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
365 msg.msg_name = NULL;
366 msg.msg_namelen = 0;
367 msg.msg_control = NULL;
368 msg.msg_controllen = 0;
369 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
370
371 if (send)
372 result = sock_sendmsg(sock, &msg);
373 else
374 result = sock_recvmsg(sock, &msg, msg.msg_flags);
375
376 if (result <= 0) {
377 if (result == 0)
378 result = -EPIPE; /* short read */
379 break;
380 }
381 if (sent)
382 *sent += result;
383 } while (msg_data_left(&msg));
384
385 memalloc_noreclaim_restore(noreclaim_flag);
386
387 return result;
388 }
389
390 /* always call with the tx_lock held */
391 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
392 {
393 struct request *req = blk_mq_rq_from_pdu(cmd);
394 struct nbd_config *config = nbd->config;
395 struct nbd_sock *nsock = config->socks[index];
396 int result;
397 struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
398 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
399 struct iov_iter from;
400 unsigned long size = blk_rq_bytes(req);
401 struct bio *bio;
402 u32 type;
403 u32 nbd_cmd_flags = 0;
404 u32 tag = blk_mq_unique_tag(req);
405 int sent = nsock->sent, skip = 0;
406
407 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
408
409 switch (req_op(req)) {
410 case REQ_OP_DISCARD:
411 type = NBD_CMD_TRIM;
412 break;
413 case REQ_OP_FLUSH:
414 type = NBD_CMD_FLUSH;
415 break;
416 case REQ_OP_WRITE:
417 type = NBD_CMD_WRITE;
418 break;
419 case REQ_OP_READ:
420 type = NBD_CMD_READ;
421 break;
422 default:
423 return -EIO;
424 }
425
426 if (rq_data_dir(req) == WRITE &&
427 (config->flags & NBD_FLAG_READ_ONLY)) {
428 dev_err_ratelimited(disk_to_dev(nbd->disk),
429 "Write on read-only\n");
430 return -EIO;
431 }
432
433 if (req->cmd_flags & REQ_FUA)
434 nbd_cmd_flags |= NBD_CMD_FLAG_FUA;
435
436 /* We did a partial send previously, and we at least sent the whole
437 * request struct, so just go and send the rest of the pages in the
438 * request.
439 */
440 if (sent) {
441 if (sent >= sizeof(request)) {
442 skip = sent - sizeof(request);
443 goto send_pages;
444 }
445 iov_iter_advance(&from, sent);
446 }
447 cmd->index = index;
448 cmd->cookie = nsock->cookie;
449 request.type = htonl(type | nbd_cmd_flags);
450 if (type != NBD_CMD_FLUSH) {
451 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
452 request.len = htonl(size);
453 }
454 memcpy(request.handle, &tag, sizeof(tag));
455
456 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
457 cmd, nbdcmd_to_ascii(type),
458 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
459 result = sock_xmit(nbd, index, 1, &from,
460 (type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
461 if (result <= 0) {
462 if (result == -ERESTARTSYS) {
463 /* If we havne't sent anything we can just return BUSY,
464 * however if we have sent something we need to make
465 * sure we only allow this req to be sent until we are
466 * completely done.
467 */
468 if (sent) {
469 nsock->pending = req;
470 nsock->sent = sent;
471 }
472 return BLK_STS_RESOURCE;
473 }
474 dev_err_ratelimited(disk_to_dev(nbd->disk),
475 "Send control failed (result %d)\n", result);
476 return -EAGAIN;
477 }
478 send_pages:
479 if (type != NBD_CMD_WRITE)
480 goto out;
481
482 bio = req->bio;
483 while (bio) {
484 struct bio *next = bio->bi_next;
485 struct bvec_iter iter;
486 struct bio_vec bvec;
487
488 bio_for_each_segment(bvec, bio, iter) {
489 bool is_last = !next && bio_iter_last(bvec, iter);
490 int flags = is_last ? 0 : MSG_MORE;
491
492 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
493 cmd, bvec.bv_len);
494 iov_iter_bvec(&from, ITER_BVEC | WRITE,
495 &bvec, 1, bvec.bv_len);
496 if (skip) {
497 if (skip >= iov_iter_count(&from)) {
498 skip -= iov_iter_count(&from);
499 continue;
500 }
501 iov_iter_advance(&from, skip);
502 skip = 0;
503 }
504 result = sock_xmit(nbd, index, 1, &from, flags, &sent);
505 if (result <= 0) {
506 if (result == -ERESTARTSYS) {
507 /* We've already sent the header, we
508 * have no choice but to set pending and
509 * return BUSY.
510 */
511 nsock->pending = req;
512 nsock->sent = sent;
513 return BLK_STS_RESOURCE;
514 }
515 dev_err(disk_to_dev(nbd->disk),
516 "Send data failed (result %d)\n",
517 result);
518 return -EAGAIN;
519 }
520 /*
521 * The completion might already have come in,
522 * so break for the last one instead of letting
523 * the iterator do it. This prevents use-after-free
524 * of the bio.
525 */
526 if (is_last)
527 break;
528 }
529 bio = next;
530 }
531 out:
532 nsock->pending = NULL;
533 nsock->sent = 0;
534 return 0;
535 }
536
537 /* NULL returned = something went wrong, inform userspace */
538 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
539 {
540 struct nbd_config *config = nbd->config;
541 int result;
542 struct nbd_reply reply;
543 struct nbd_cmd *cmd;
544 struct request *req = NULL;
545 u16 hwq;
546 u32 tag;
547 struct kvec iov = {.iov_base = &reply, .iov_len = sizeof(reply)};
548 struct iov_iter to;
549
550 reply.magic = 0;
551 iov_iter_kvec(&to, READ | ITER_KVEC, &iov, 1, sizeof(reply));
552 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
553 if (result <= 0) {
554 if (!nbd_disconnected(config))
555 dev_err(disk_to_dev(nbd->disk),
556 "Receive control failed (result %d)\n", result);
557 return ERR_PTR(result);
558 }
559
560 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
561 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
562 (unsigned long)ntohl(reply.magic));
563 return ERR_PTR(-EPROTO);
564 }
565
566 memcpy(&tag, reply.handle, sizeof(u32));
567
568 hwq = blk_mq_unique_tag_to_hwq(tag);
569 if (hwq < nbd->tag_set.nr_hw_queues)
570 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
571 blk_mq_unique_tag_to_tag(tag));
572 if (!req || !blk_mq_request_started(req)) {
573 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
574 tag, req);
575 return ERR_PTR(-ENOENT);
576 }
577 cmd = blk_mq_rq_to_pdu(req);
578 if (ntohl(reply.error)) {
579 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
580 ntohl(reply.error));
581 cmd->status = BLK_STS_IOERR;
582 return cmd;
583 }
584
585 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd);
586 if (rq_data_dir(req) != WRITE) {
587 struct req_iterator iter;
588 struct bio_vec bvec;
589
590 rq_for_each_segment(bvec, req, iter) {
591 iov_iter_bvec(&to, ITER_BVEC | READ,
592 &bvec, 1, bvec.bv_len);
593 result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
594 if (result <= 0) {
595 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
596 result);
597 /*
598 * If we've disconnected or we only have 1
599 * connection then we need to make sure we
600 * complete this request, otherwise error out
601 * and let the timeout stuff handle resubmitting
602 * this request onto another connection.
603 */
604 if (nbd_disconnected(config) ||
605 config->num_connections <= 1) {
606 cmd->status = BLK_STS_IOERR;
607 return cmd;
608 }
609 return ERR_PTR(-EIO);
610 }
611 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
612 cmd, bvec.bv_len);
613 }
614 } else {
615 /* See the comment in nbd_queue_rq. */
616 wait_for_completion(&cmd->send_complete);
617 }
618 return cmd;
619 }
620
621 static void recv_work(struct work_struct *work)
622 {
623 struct recv_thread_args *args = container_of(work,
624 struct recv_thread_args,
625 work);
626 struct nbd_device *nbd = args->nbd;
627 struct nbd_config *config = nbd->config;
628 struct nbd_cmd *cmd;
629 int ret = 0;
630
631 while (1) {
632 cmd = nbd_read_stat(nbd, args->index);
633 if (IS_ERR(cmd)) {
634 struct nbd_sock *nsock = config->socks[args->index];
635
636 mutex_lock(&nsock->tx_lock);
637 nbd_mark_nsock_dead(nbd, nsock, 1);
638 mutex_unlock(&nsock->tx_lock);
639 ret = PTR_ERR(cmd);
640 break;
641 }
642
643 blk_mq_complete_request(blk_mq_rq_from_pdu(cmd));
644 }
645 atomic_dec(&config->recv_threads);
646 wake_up(&config->recv_wq);
647 nbd_config_put(nbd);
648 kfree(args);
649 }
650
651 static void nbd_clear_req(struct request *req, void *data, bool reserved)
652 {
653 struct nbd_cmd *cmd;
654
655 if (!blk_mq_request_started(req))
656 return;
657 cmd = blk_mq_rq_to_pdu(req);
658 cmd->status = BLK_STS_IOERR;
659 blk_mq_complete_request(req);
660 }
661
662 static void nbd_clear_que(struct nbd_device *nbd)
663 {
664 blk_mq_quiesce_queue(nbd->disk->queue);
665 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
666 blk_mq_unquiesce_queue(nbd->disk->queue);
667 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
668 }
669
670 static int find_fallback(struct nbd_device *nbd, int index)
671 {
672 struct nbd_config *config = nbd->config;
673 int new_index = -1;
674 struct nbd_sock *nsock = config->socks[index];
675 int fallback = nsock->fallback_index;
676
677 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
678 return new_index;
679
680 if (config->num_connections <= 1) {
681 dev_err_ratelimited(disk_to_dev(nbd->disk),
682 "Attempted send on invalid socket\n");
683 return new_index;
684 }
685
686 if (fallback >= 0 && fallback < config->num_connections &&
687 !config->socks[fallback]->dead)
688 return fallback;
689
690 if (nsock->fallback_index < 0 ||
691 nsock->fallback_index >= config->num_connections ||
692 config->socks[nsock->fallback_index]->dead) {
693 int i;
694 for (i = 0; i < config->num_connections; i++) {
695 if (i == index)
696 continue;
697 if (!config->socks[i]->dead) {
698 new_index = i;
699 break;
700 }
701 }
702 nsock->fallback_index = new_index;
703 if (new_index < 0) {
704 dev_err_ratelimited(disk_to_dev(nbd->disk),
705 "Dead connection, failed to find a fallback\n");
706 return new_index;
707 }
708 }
709 new_index = nsock->fallback_index;
710 return new_index;
711 }
712
713 static int wait_for_reconnect(struct nbd_device *nbd)
714 {
715 struct nbd_config *config = nbd->config;
716 if (!config->dead_conn_timeout)
717 return 0;
718 if (test_bit(NBD_DISCONNECTED, &config->runtime_flags))
719 return 0;
720 wait_event_interruptible_timeout(config->conn_wait,
721 atomic_read(&config->live_connections),
722 config->dead_conn_timeout);
723 return atomic_read(&config->live_connections);
724 }
725
726 static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
727 {
728 struct request *req = blk_mq_rq_from_pdu(cmd);
729 struct nbd_device *nbd = cmd->nbd;
730 struct nbd_config *config;
731 struct nbd_sock *nsock;
732 int ret;
733
734 if (!refcount_inc_not_zero(&nbd->config_refs)) {
735 dev_err_ratelimited(disk_to_dev(nbd->disk),
736 "Socks array is empty\n");
737 return -EINVAL;
738 }
739 config = nbd->config;
740
741 if (index >= config->num_connections) {
742 dev_err_ratelimited(disk_to_dev(nbd->disk),
743 "Attempted send on invalid socket\n");
744 nbd_config_put(nbd);
745 return -EINVAL;
746 }
747 cmd->status = BLK_STS_OK;
748 again:
749 nsock = config->socks[index];
750 mutex_lock(&nsock->tx_lock);
751 if (nsock->dead) {
752 int old_index = index;
753 index = find_fallback(nbd, index);
754 mutex_unlock(&nsock->tx_lock);
755 if (index < 0) {
756 if (wait_for_reconnect(nbd)) {
757 index = old_index;
758 goto again;
759 }
760 /* All the sockets should already be down at this point,
761 * we just want to make sure that DISCONNECTED is set so
762 * any requests that come in that were queue'ed waiting
763 * for the reconnect timer don't trigger the timer again
764 * and instead just error out.
765 */
766 sock_shutdown(nbd);
767 nbd_config_put(nbd);
768 return -EIO;
769 }
770 goto again;
771 }
772
773 /* Handle the case that we have a pending request that was partially
774 * transmitted that _has_ to be serviced first. We need to call requeue
775 * here so that it gets put _after_ the request that is already on the
776 * dispatch list.
777 */
778 if (unlikely(nsock->pending && nsock->pending != req)) {
779 blk_mq_requeue_request(req, true);
780 ret = 0;
781 goto out;
782 }
783 /*
784 * Some failures are related to the link going down, so anything that
785 * returns EAGAIN can be retried on a different socket.
786 */
787 ret = nbd_send_cmd(nbd, cmd, index);
788 if (ret == -EAGAIN) {
789 dev_err_ratelimited(disk_to_dev(nbd->disk),
790 "Request send failed trying another connection\n");
791 nbd_mark_nsock_dead(nbd, nsock, 1);
792 mutex_unlock(&nsock->tx_lock);
793 goto again;
794 }
795 out:
796 mutex_unlock(&nsock->tx_lock);
797 nbd_config_put(nbd);
798 return ret;
799 }
800
801 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
802 const struct blk_mq_queue_data *bd)
803 {
804 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
805 int ret;
806
807 /*
808 * Since we look at the bio's to send the request over the network we
809 * need to make sure the completion work doesn't mark this request done
810 * before we are done doing our send. This keeps us from dereferencing
811 * freed data if we have particularly fast completions (ie we get the
812 * completion before we exit sock_xmit on the last bvec) or in the case
813 * that the server is misbehaving (or there was an error) before we're
814 * done sending everything over the wire.
815 */
816 init_completion(&cmd->send_complete);
817 blk_mq_start_request(bd->rq);
818
819 /* We can be called directly from the user space process, which means we
820 * could possibly have signals pending so our sendmsg will fail. In
821 * this case we need to return that we are busy, otherwise error out as
822 * appropriate.
823 */
824 ret = nbd_handle_cmd(cmd, hctx->queue_num);
825 complete(&cmd->send_complete);
826
827 return ret < 0 ? BLK_STS_IOERR : BLK_STS_OK;
828 }
829
830 static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
831 bool netlink)
832 {
833 struct nbd_config *config = nbd->config;
834 struct socket *sock;
835 struct nbd_sock **socks;
836 struct nbd_sock *nsock;
837 int err;
838
839 sock = sockfd_lookup(arg, &err);
840 if (!sock)
841 return err;
842
843 if (!netlink && !nbd->task_setup &&
844 !test_bit(NBD_BOUND, &config->runtime_flags))
845 nbd->task_setup = current;
846
847 if (!netlink &&
848 (nbd->task_setup != current ||
849 test_bit(NBD_BOUND, &config->runtime_flags))) {
850 dev_err(disk_to_dev(nbd->disk),
851 "Device being setup by another task");
852 sockfd_put(sock);
853 return -EBUSY;
854 }
855
856 socks = krealloc(config->socks, (config->num_connections + 1) *
857 sizeof(struct nbd_sock *), GFP_KERNEL);
858 if (!socks) {
859 sockfd_put(sock);
860 return -ENOMEM;
861 }
862 nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
863 if (!nsock) {
864 sockfd_put(sock);
865 return -ENOMEM;
866 }
867
868 config->socks = socks;
869
870 nsock->fallback_index = -1;
871 nsock->dead = false;
872 mutex_init(&nsock->tx_lock);
873 nsock->sock = sock;
874 nsock->pending = NULL;
875 nsock->sent = 0;
876 nsock->cookie = 0;
877 socks[config->num_connections++] = nsock;
878 atomic_inc(&config->live_connections);
879
880 return 0;
881 }
882
883 static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
884 {
885 struct nbd_config *config = nbd->config;
886 struct socket *sock, *old;
887 struct recv_thread_args *args;
888 int i;
889 int err;
890
891 sock = sockfd_lookup(arg, &err);
892 if (!sock)
893 return err;
894
895 args = kzalloc(sizeof(*args), GFP_KERNEL);
896 if (!args) {
897 sockfd_put(sock);
898 return -ENOMEM;
899 }
900
901 for (i = 0; i < config->num_connections; i++) {
902 struct nbd_sock *nsock = config->socks[i];
903
904 if (!nsock->dead)
905 continue;
906
907 mutex_lock(&nsock->tx_lock);
908 if (!nsock->dead) {
909 mutex_unlock(&nsock->tx_lock);
910 continue;
911 }
912 sk_set_memalloc(sock->sk);
913 sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
914 atomic_inc(&config->recv_threads);
915 refcount_inc(&nbd->config_refs);
916 old = nsock->sock;
917 nsock->fallback_index = -1;
918 nsock->sock = sock;
919 nsock->dead = false;
920 INIT_WORK(&args->work, recv_work);
921 args->index = i;
922 args->nbd = nbd;
923 nsock->cookie++;
924 mutex_unlock(&nsock->tx_lock);
925 sockfd_put(old);
926
927 /* We take the tx_mutex in an error path in the recv_work, so we
928 * need to queue_work outside of the tx_mutex.
929 */
930 queue_work(recv_workqueue, &args->work);
931
932 atomic_inc(&config->live_connections);
933 wake_up(&config->conn_wait);
934 return 0;
935 }
936 sockfd_put(sock);
937 kfree(args);
938 return -ENOSPC;
939 }
940
941 static void nbd_bdev_reset(struct block_device *bdev)
942 {
943 if (bdev->bd_openers > 1)
944 return;
945 bd_set_size(bdev, 0);
946 if (max_part > 0) {
947 blkdev_reread_part(bdev);
948 bdev->bd_invalidated = 1;
949 }
950 }
951
952 static void nbd_parse_flags(struct nbd_device *nbd)
953 {
954 struct nbd_config *config = nbd->config;
955 if (config->flags & NBD_FLAG_READ_ONLY)
956 set_disk_ro(nbd->disk, true);
957 else
958 set_disk_ro(nbd->disk, false);
959 if (config->flags & NBD_FLAG_SEND_TRIM)
960 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
961 if (config->flags & NBD_FLAG_SEND_FLUSH) {
962 if (config->flags & NBD_FLAG_SEND_FUA)
963 blk_queue_write_cache(nbd->disk->queue, true, true);
964 else
965 blk_queue_write_cache(nbd->disk->queue, true, false);
966 }
967 else
968 blk_queue_write_cache(nbd->disk->queue, false, false);
969 }
970
971 static void send_disconnects(struct nbd_device *nbd)
972 {
973 struct nbd_config *config = nbd->config;
974 struct nbd_request request = {
975 .magic = htonl(NBD_REQUEST_MAGIC),
976 .type = htonl(NBD_CMD_DISC),
977 };
978 struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
979 struct iov_iter from;
980 int i, ret;
981
982 for (i = 0; i < config->num_connections; i++) {
983 iov_iter_kvec(&from, WRITE | ITER_KVEC, &iov, 1, sizeof(request));
984 ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
985 if (ret <= 0)
986 dev_err(disk_to_dev(nbd->disk),
987 "Send disconnect failed %d\n", ret);
988 }
989 }
990
991 static int nbd_disconnect(struct nbd_device *nbd)
992 {
993 struct nbd_config *config = nbd->config;
994
995 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
996 if (!test_and_set_bit(NBD_DISCONNECT_REQUESTED,
997 &config->runtime_flags))
998 send_disconnects(nbd);
999 return 0;
1000 }
1001
1002 static void nbd_clear_sock(struct nbd_device *nbd)
1003 {
1004 sock_shutdown(nbd);
1005 nbd_clear_que(nbd);
1006 nbd->task_setup = NULL;
1007 }
1008
1009 static void nbd_config_put(struct nbd_device *nbd)
1010 {
1011 if (refcount_dec_and_mutex_lock(&nbd->config_refs,
1012 &nbd->config_lock)) {
1013 struct nbd_config *config = nbd->config;
1014 nbd_dev_dbg_close(nbd);
1015 nbd_size_clear(nbd);
1016 if (test_and_clear_bit(NBD_HAS_PID_FILE,
1017 &config->runtime_flags))
1018 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
1019 nbd->task_recv = NULL;
1020 nbd_clear_sock(nbd);
1021 if (config->num_connections) {
1022 int i;
1023 for (i = 0; i < config->num_connections; i++) {
1024 sockfd_put(config->socks[i]->sock);
1025 kfree(config->socks[i]);
1026 }
1027 kfree(config->socks);
1028 }
1029 kfree(nbd->config);
1030 nbd->config = NULL;
1031
1032 nbd->tag_set.timeout = 0;
1033 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
1034
1035 mutex_unlock(&nbd->config_lock);
1036 nbd_put(nbd);
1037 module_put(THIS_MODULE);
1038 }
1039 }
1040
1041 static int nbd_start_device(struct nbd_device *nbd)
1042 {
1043 struct nbd_config *config = nbd->config;
1044 int num_connections = config->num_connections;
1045 int error = 0, i;
1046
1047 if (nbd->task_recv)
1048 return -EBUSY;
1049 if (!config->socks)
1050 return -EINVAL;
1051 if (num_connections > 1 &&
1052 !(config->flags & NBD_FLAG_CAN_MULTI_CONN)) {
1053 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
1054 return -EINVAL;
1055 }
1056
1057 blk_mq_update_nr_hw_queues(&nbd->tag_set, config->num_connections);
1058 nbd->task_recv = current;
1059
1060 nbd_parse_flags(nbd);
1061
1062 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
1063 if (error) {
1064 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
1065 return error;
1066 }
1067 set_bit(NBD_HAS_PID_FILE, &config->runtime_flags);
1068
1069 nbd_dev_dbg_init(nbd);
1070 for (i = 0; i < num_connections; i++) {
1071 struct recv_thread_args *args;
1072
1073 args = kzalloc(sizeof(*args), GFP_KERNEL);
1074 if (!args) {
1075 sock_shutdown(nbd);
1076 return -ENOMEM;
1077 }
1078 sk_set_memalloc(config->socks[i]->sock->sk);
1079 config->socks[i]->sock->sk->sk_sndtimeo = nbd->tag_set.timeout;
1080 atomic_inc(&config->recv_threads);
1081 refcount_inc(&nbd->config_refs);
1082 INIT_WORK(&args->work, recv_work);
1083 args->nbd = nbd;
1084 args->index = i;
1085 queue_work(recv_workqueue, &args->work);
1086 }
1087 return error;
1088 }
1089
1090 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
1091 {
1092 struct nbd_config *config = nbd->config;
1093 int ret;
1094
1095 ret = nbd_start_device(nbd);
1096 if (ret)
1097 return ret;
1098
1099 bd_set_size(bdev, config->bytesize);
1100 if (max_part)
1101 bdev->bd_invalidated = 1;
1102 mutex_unlock(&nbd->config_lock);
1103 ret = wait_event_interruptible(config->recv_wq,
1104 atomic_read(&config->recv_threads) == 0);
1105 if (ret)
1106 sock_shutdown(nbd);
1107 mutex_lock(&nbd->config_lock);
1108 bd_set_size(bdev, 0);
1109 /* user requested, ignore socket errors */
1110 if (test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags))
1111 ret = 0;
1112 if (test_bit(NBD_TIMEDOUT, &config->runtime_flags))
1113 ret = -ETIMEDOUT;
1114 return ret;
1115 }
1116
1117 static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
1118 struct block_device *bdev)
1119 {
1120 sock_shutdown(nbd);
1121 kill_bdev(bdev);
1122 nbd_bdev_reset(bdev);
1123 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1124 &nbd->config->runtime_flags))
1125 nbd_config_put(nbd);
1126 }
1127
1128 /* Must be called with config_lock held */
1129 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
1130 unsigned int cmd, unsigned long arg)
1131 {
1132 struct nbd_config *config = nbd->config;
1133
1134 switch (cmd) {
1135 case NBD_DISCONNECT:
1136 return nbd_disconnect(nbd);
1137 case NBD_CLEAR_SOCK:
1138 nbd_clear_sock_ioctl(nbd, bdev);
1139 return 0;
1140 case NBD_SET_SOCK:
1141 return nbd_add_socket(nbd, arg, false);
1142 case NBD_SET_BLKSIZE:
1143 nbd_size_set(nbd, arg,
1144 div_s64(config->bytesize, arg));
1145 return 0;
1146 case NBD_SET_SIZE:
1147 nbd_size_set(nbd, config->blksize,
1148 div_s64(arg, config->blksize));
1149 return 0;
1150 case NBD_SET_SIZE_BLOCKS:
1151 nbd_size_set(nbd, config->blksize, arg);
1152 return 0;
1153 case NBD_SET_TIMEOUT:
1154 if (arg) {
1155 nbd->tag_set.timeout = arg * HZ;
1156 blk_queue_rq_timeout(nbd->disk->queue, arg * HZ);
1157 }
1158 return 0;
1159
1160 case NBD_SET_FLAGS:
1161 config->flags = arg;
1162 return 0;
1163 case NBD_DO_IT:
1164 return nbd_start_device_ioctl(nbd, bdev);
1165 case NBD_CLEAR_QUE:
1166 /*
1167 * This is for compatibility only. The queue is always cleared
1168 * by NBD_DO_IT or NBD_CLEAR_SOCK.
1169 */
1170 return 0;
1171 case NBD_PRINT_DEBUG:
1172 /*
1173 * For compatibility only, we no longer keep a list of
1174 * outstanding requests.
1175 */
1176 return 0;
1177 }
1178 return -ENOTTY;
1179 }
1180
1181 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
1182 unsigned int cmd, unsigned long arg)
1183 {
1184 struct nbd_device *nbd = bdev->bd_disk->private_data;
1185 struct nbd_config *config = nbd->config;
1186 int error = -EINVAL;
1187
1188 if (!capable(CAP_SYS_ADMIN))
1189 return -EPERM;
1190
1191 mutex_lock(&nbd->config_lock);
1192
1193 /* Don't allow ioctl operations on a nbd device that was created with
1194 * netlink, unless it's DISCONNECT or CLEAR_SOCK, which are fine.
1195 */
1196 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1197 (cmd == NBD_DISCONNECT || cmd == NBD_CLEAR_SOCK))
1198 error = __nbd_ioctl(bdev, nbd, cmd, arg);
1199 else
1200 dev_err(nbd_to_dev(nbd), "Cannot use ioctl interface on a netlink controlled device.\n");
1201 mutex_unlock(&nbd->config_lock);
1202 return error;
1203 }
1204
1205 static struct nbd_config *nbd_alloc_config(void)
1206 {
1207 struct nbd_config *config;
1208
1209 config = kzalloc(sizeof(struct nbd_config), GFP_NOFS);
1210 if (!config)
1211 return NULL;
1212 atomic_set(&config->recv_threads, 0);
1213 init_waitqueue_head(&config->recv_wq);
1214 init_waitqueue_head(&config->conn_wait);
1215 config->blksize = 1024;
1216 atomic_set(&config->live_connections, 0);
1217 try_module_get(THIS_MODULE);
1218 return config;
1219 }
1220
1221 static int nbd_open(struct block_device *bdev, fmode_t mode)
1222 {
1223 struct nbd_device *nbd;
1224 int ret = 0;
1225
1226 mutex_lock(&nbd_index_mutex);
1227 nbd = bdev->bd_disk->private_data;
1228 if (!nbd) {
1229 ret = -ENXIO;
1230 goto out;
1231 }
1232 if (!refcount_inc_not_zero(&nbd->refs)) {
1233 ret = -ENXIO;
1234 goto out;
1235 }
1236 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1237 struct nbd_config *config;
1238
1239 mutex_lock(&nbd->config_lock);
1240 if (refcount_inc_not_zero(&nbd->config_refs)) {
1241 mutex_unlock(&nbd->config_lock);
1242 goto out;
1243 }
1244 config = nbd->config = nbd_alloc_config();
1245 if (!config) {
1246 ret = -ENOMEM;
1247 mutex_unlock(&nbd->config_lock);
1248 goto out;
1249 }
1250 refcount_set(&nbd->config_refs, 1);
1251 refcount_inc(&nbd->refs);
1252 mutex_unlock(&nbd->config_lock);
1253 }
1254 out:
1255 mutex_unlock(&nbd_index_mutex);
1256 return ret;
1257 }
1258
1259 static void nbd_release(struct gendisk *disk, fmode_t mode)
1260 {
1261 struct nbd_device *nbd = disk->private_data;
1262 nbd_config_put(nbd);
1263 nbd_put(nbd);
1264 }
1265
1266 static const struct block_device_operations nbd_fops =
1267 {
1268 .owner = THIS_MODULE,
1269 .open = nbd_open,
1270 .release = nbd_release,
1271 .ioctl = nbd_ioctl,
1272 .compat_ioctl = nbd_ioctl,
1273 };
1274
1275 #if IS_ENABLED(CONFIG_DEBUG_FS)
1276
1277 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
1278 {
1279 struct nbd_device *nbd = s->private;
1280
1281 if (nbd->task_recv)
1282 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
1283
1284 return 0;
1285 }
1286
1287 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
1288 {
1289 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
1290 }
1291
1292 static const struct file_operations nbd_dbg_tasks_ops = {
1293 .open = nbd_dbg_tasks_open,
1294 .read = seq_read,
1295 .llseek = seq_lseek,
1296 .release = single_release,
1297 };
1298
1299 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
1300 {
1301 struct nbd_device *nbd = s->private;
1302 u32 flags = nbd->config->flags;
1303
1304 seq_printf(s, "Hex: 0x%08x\n\n", flags);
1305
1306 seq_puts(s, "Known flags:\n");
1307
1308 if (flags & NBD_FLAG_HAS_FLAGS)
1309 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
1310 if (flags & NBD_FLAG_READ_ONLY)
1311 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
1312 if (flags & NBD_FLAG_SEND_FLUSH)
1313 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
1314 if (flags & NBD_FLAG_SEND_FUA)
1315 seq_puts(s, "NBD_FLAG_SEND_FUA\n");
1316 if (flags & NBD_FLAG_SEND_TRIM)
1317 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
1318
1319 return 0;
1320 }
1321
1322 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
1323 {
1324 return single_open(file, nbd_dbg_flags_show, inode->i_private);
1325 }
1326
1327 static const struct file_operations nbd_dbg_flags_ops = {
1328 .open = nbd_dbg_flags_open,
1329 .read = seq_read,
1330 .llseek = seq_lseek,
1331 .release = single_release,
1332 };
1333
1334 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1335 {
1336 struct dentry *dir;
1337 struct nbd_config *config = nbd->config;
1338
1339 if (!nbd_dbg_dir)
1340 return -EIO;
1341
1342 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
1343 if (!dir) {
1344 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
1345 nbd_name(nbd));
1346 return -EIO;
1347 }
1348 config->dbg_dir = dir;
1349
1350 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
1351 debugfs_create_u64("size_bytes", 0444, dir, &config->bytesize);
1352 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
1353 debugfs_create_u64("blocksize", 0444, dir, &config->blksize);
1354 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
1355
1356 return 0;
1357 }
1358
1359 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1360 {
1361 debugfs_remove_recursive(nbd->config->dbg_dir);
1362 }
1363
1364 static int nbd_dbg_init(void)
1365 {
1366 struct dentry *dbg_dir;
1367
1368 dbg_dir = debugfs_create_dir("nbd", NULL);
1369 if (!dbg_dir)
1370 return -EIO;
1371
1372 nbd_dbg_dir = dbg_dir;
1373
1374 return 0;
1375 }
1376
1377 static void nbd_dbg_close(void)
1378 {
1379 debugfs_remove_recursive(nbd_dbg_dir);
1380 }
1381
1382 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
1383
1384 static int nbd_dev_dbg_init(struct nbd_device *nbd)
1385 {
1386 return 0;
1387 }
1388
1389 static void nbd_dev_dbg_close(struct nbd_device *nbd)
1390 {
1391 }
1392
1393 static int nbd_dbg_init(void)
1394 {
1395 return 0;
1396 }
1397
1398 static void nbd_dbg_close(void)
1399 {
1400 }
1401
1402 #endif
1403
1404 static int nbd_init_request(struct blk_mq_tag_set *set, struct request *rq,
1405 unsigned int hctx_idx, unsigned int numa_node)
1406 {
1407 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
1408 cmd->nbd = set->driver_data;
1409 return 0;
1410 }
1411
1412 static const struct blk_mq_ops nbd_mq_ops = {
1413 .queue_rq = nbd_queue_rq,
1414 .complete = nbd_complete_rq,
1415 .init_request = nbd_init_request,
1416 .timeout = nbd_xmit_timeout,
1417 };
1418
1419 static int nbd_dev_add(int index)
1420 {
1421 struct nbd_device *nbd;
1422 struct gendisk *disk;
1423 struct request_queue *q;
1424 int err = -ENOMEM;
1425
1426 nbd = kzalloc(sizeof(struct nbd_device), GFP_KERNEL);
1427 if (!nbd)
1428 goto out;
1429
1430 disk = alloc_disk(1 << part_shift);
1431 if (!disk)
1432 goto out_free_nbd;
1433
1434 if (index >= 0) {
1435 err = idr_alloc(&nbd_index_idr, nbd, index, index + 1,
1436 GFP_KERNEL);
1437 if (err == -ENOSPC)
1438 err = -EEXIST;
1439 } else {
1440 err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
1441 if (err >= 0)
1442 index = err;
1443 }
1444 if (err < 0)
1445 goto out_free_disk;
1446
1447 nbd->index = index;
1448 nbd->disk = disk;
1449 nbd->tag_set.ops = &nbd_mq_ops;
1450 nbd->tag_set.nr_hw_queues = 1;
1451 nbd->tag_set.queue_depth = 128;
1452 nbd->tag_set.numa_node = NUMA_NO_NODE;
1453 nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
1454 nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
1455 BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING;
1456 nbd->tag_set.driver_data = nbd;
1457
1458 err = blk_mq_alloc_tag_set(&nbd->tag_set);
1459 if (err)
1460 goto out_free_idr;
1461
1462 q = blk_mq_init_queue(&nbd->tag_set);
1463 if (IS_ERR(q)) {
1464 err = PTR_ERR(q);
1465 goto out_free_tags;
1466 }
1467 disk->queue = q;
1468
1469 /*
1470 * Tell the block layer that we are not a rotational device
1471 */
1472 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
1473 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue);
1474 disk->queue->limits.discard_granularity = 512;
1475 blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
1476 blk_queue_max_segment_size(disk->queue, UINT_MAX);
1477 blk_queue_max_segments(disk->queue, USHRT_MAX);
1478 blk_queue_max_hw_sectors(disk->queue, 65536);
1479 disk->queue->limits.max_sectors = 256;
1480
1481 mutex_init(&nbd->config_lock);
1482 refcount_set(&nbd->config_refs, 0);
1483 refcount_set(&nbd->refs, 1);
1484 INIT_LIST_HEAD(&nbd->list);
1485 disk->major = NBD_MAJOR;
1486 disk->first_minor = index << part_shift;
1487 disk->fops = &nbd_fops;
1488 disk->private_data = nbd;
1489 sprintf(disk->disk_name, "nbd%d", index);
1490 add_disk(disk);
1491 nbd_total_devices++;
1492 return index;
1493
1494 out_free_tags:
1495 blk_mq_free_tag_set(&nbd->tag_set);
1496 out_free_idr:
1497 idr_remove(&nbd_index_idr, index);
1498 out_free_disk:
1499 put_disk(disk);
1500 out_free_nbd:
1501 kfree(nbd);
1502 out:
1503 return err;
1504 }
1505
1506 static int find_free_cb(int id, void *ptr, void *data)
1507 {
1508 struct nbd_device *nbd = ptr;
1509 struct nbd_device **found = data;
1510
1511 if (!refcount_read(&nbd->config_refs)) {
1512 *found = nbd;
1513 return 1;
1514 }
1515 return 0;
1516 }
1517
1518 /* Netlink interface. */
1519 static struct nla_policy nbd_attr_policy[NBD_ATTR_MAX + 1] = {
1520 [NBD_ATTR_INDEX] = { .type = NLA_U32 },
1521 [NBD_ATTR_SIZE_BYTES] = { .type = NLA_U64 },
1522 [NBD_ATTR_BLOCK_SIZE_BYTES] = { .type = NLA_U64 },
1523 [NBD_ATTR_TIMEOUT] = { .type = NLA_U64 },
1524 [NBD_ATTR_SERVER_FLAGS] = { .type = NLA_U64 },
1525 [NBD_ATTR_CLIENT_FLAGS] = { .type = NLA_U64 },
1526 [NBD_ATTR_SOCKETS] = { .type = NLA_NESTED},
1527 [NBD_ATTR_DEAD_CONN_TIMEOUT] = { .type = NLA_U64 },
1528 [NBD_ATTR_DEVICE_LIST] = { .type = NLA_NESTED},
1529 };
1530
1531 static struct nla_policy nbd_sock_policy[NBD_SOCK_MAX + 1] = {
1532 [NBD_SOCK_FD] = { .type = NLA_U32 },
1533 };
1534
1535 /* We don't use this right now since we don't parse the incoming list, but we
1536 * still want it here so userspace knows what to expect.
1537 */
1538 static struct nla_policy __attribute__((unused))
1539 nbd_device_policy[NBD_DEVICE_ATTR_MAX + 1] = {
1540 [NBD_DEVICE_INDEX] = { .type = NLA_U32 },
1541 [NBD_DEVICE_CONNECTED] = { .type = NLA_U8 },
1542 };
1543
1544 static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
1545 {
1546 struct nbd_device *nbd = NULL;
1547 struct nbd_config *config;
1548 int index = -1;
1549 int ret;
1550 bool put_dev = false;
1551
1552 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1553 return -EPERM;
1554
1555 if (info->attrs[NBD_ATTR_INDEX])
1556 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1557 if (!info->attrs[NBD_ATTR_SOCKETS]) {
1558 printk(KERN_ERR "nbd: must specify at least one socket\n");
1559 return -EINVAL;
1560 }
1561 if (!info->attrs[NBD_ATTR_SIZE_BYTES]) {
1562 printk(KERN_ERR "nbd: must specify a size in bytes for the device\n");
1563 return -EINVAL;
1564 }
1565 again:
1566 mutex_lock(&nbd_index_mutex);
1567 if (index == -1) {
1568 ret = idr_for_each(&nbd_index_idr, &find_free_cb, &nbd);
1569 if (ret == 0) {
1570 int new_index;
1571 new_index = nbd_dev_add(-1);
1572 if (new_index < 0) {
1573 mutex_unlock(&nbd_index_mutex);
1574 printk(KERN_ERR "nbd: failed to add new device\n");
1575 return ret;
1576 }
1577 nbd = idr_find(&nbd_index_idr, new_index);
1578 }
1579 } else {
1580 nbd = idr_find(&nbd_index_idr, index);
1581 }
1582 if (!nbd) {
1583 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1584 index);
1585 mutex_unlock(&nbd_index_mutex);
1586 return -EINVAL;
1587 }
1588 if (!refcount_inc_not_zero(&nbd->refs)) {
1589 mutex_unlock(&nbd_index_mutex);
1590 if (index == -1)
1591 goto again;
1592 printk(KERN_ERR "nbd: device at index %d is going down\n",
1593 index);
1594 return -EINVAL;
1595 }
1596 mutex_unlock(&nbd_index_mutex);
1597
1598 mutex_lock(&nbd->config_lock);
1599 if (refcount_read(&nbd->config_refs)) {
1600 mutex_unlock(&nbd->config_lock);
1601 nbd_put(nbd);
1602 if (index == -1)
1603 goto again;
1604 printk(KERN_ERR "nbd: nbd%d already in use\n", index);
1605 return -EBUSY;
1606 }
1607 if (WARN_ON(nbd->config)) {
1608 mutex_unlock(&nbd->config_lock);
1609 nbd_put(nbd);
1610 return -EINVAL;
1611 }
1612 config = nbd->config = nbd_alloc_config();
1613 if (!nbd->config) {
1614 mutex_unlock(&nbd->config_lock);
1615 nbd_put(nbd);
1616 printk(KERN_ERR "nbd: couldn't allocate config\n");
1617 return -ENOMEM;
1618 }
1619 refcount_set(&nbd->config_refs, 1);
1620 set_bit(NBD_BOUND, &config->runtime_flags);
1621
1622 if (info->attrs[NBD_ATTR_SIZE_BYTES]) {
1623 u64 bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
1624 nbd_size_set(nbd, config->blksize,
1625 div64_u64(bytes, config->blksize));
1626 }
1627 if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
1628 u64 bsize =
1629 nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
1630 nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize));
1631 }
1632 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1633 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1634 nbd->tag_set.timeout = timeout * HZ;
1635 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1636 }
1637 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1638 config->dead_conn_timeout =
1639 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1640 config->dead_conn_timeout *= HZ;
1641 }
1642 if (info->attrs[NBD_ATTR_SERVER_FLAGS])
1643 config->flags =
1644 nla_get_u64(info->attrs[NBD_ATTR_SERVER_FLAGS]);
1645 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1646 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1647 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1648 set_bit(NBD_DESTROY_ON_DISCONNECT,
1649 &config->runtime_flags);
1650 put_dev = true;
1651 }
1652 }
1653
1654 if (info->attrs[NBD_ATTR_SOCKETS]) {
1655 struct nlattr *attr;
1656 int rem, fd;
1657
1658 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1659 rem) {
1660 struct nlattr *socks[NBD_SOCK_MAX+1];
1661
1662 if (nla_type(attr) != NBD_SOCK_ITEM) {
1663 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1664 ret = -EINVAL;
1665 goto out;
1666 }
1667 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1668 nbd_sock_policy, info->extack);
1669 if (ret != 0) {
1670 printk(KERN_ERR "nbd: error processing sock list\n");
1671 ret = -EINVAL;
1672 goto out;
1673 }
1674 if (!socks[NBD_SOCK_FD])
1675 continue;
1676 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1677 ret = nbd_add_socket(nbd, fd, true);
1678 if (ret)
1679 goto out;
1680 }
1681 }
1682 ret = nbd_start_device(nbd);
1683 out:
1684 mutex_unlock(&nbd->config_lock);
1685 if (!ret) {
1686 set_bit(NBD_HAS_CONFIG_REF, &config->runtime_flags);
1687 refcount_inc(&nbd->config_refs);
1688 nbd_connect_reply(info, nbd->index);
1689 }
1690 nbd_config_put(nbd);
1691 if (put_dev)
1692 nbd_put(nbd);
1693 return ret;
1694 }
1695
1696 static int nbd_genl_disconnect(struct sk_buff *skb, struct genl_info *info)
1697 {
1698 struct nbd_device *nbd;
1699 int index;
1700
1701 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1702 return -EPERM;
1703
1704 if (!info->attrs[NBD_ATTR_INDEX]) {
1705 printk(KERN_ERR "nbd: must specify an index to disconnect\n");
1706 return -EINVAL;
1707 }
1708 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1709 mutex_lock(&nbd_index_mutex);
1710 nbd = idr_find(&nbd_index_idr, index);
1711 if (!nbd) {
1712 mutex_unlock(&nbd_index_mutex);
1713 printk(KERN_ERR "nbd: couldn't find device at index %d\n",
1714 index);
1715 return -EINVAL;
1716 }
1717 if (!refcount_inc_not_zero(&nbd->refs)) {
1718 mutex_unlock(&nbd_index_mutex);
1719 printk(KERN_ERR "nbd: device at index %d is going down\n",
1720 index);
1721 return -EINVAL;
1722 }
1723 mutex_unlock(&nbd_index_mutex);
1724 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1725 nbd_put(nbd);
1726 return 0;
1727 }
1728 mutex_lock(&nbd->config_lock);
1729 nbd_disconnect(nbd);
1730 mutex_unlock(&nbd->config_lock);
1731 if (test_and_clear_bit(NBD_HAS_CONFIG_REF,
1732 &nbd->config->runtime_flags))
1733 nbd_config_put(nbd);
1734 nbd_config_put(nbd);
1735 nbd_put(nbd);
1736 return 0;
1737 }
1738
1739 static int nbd_genl_reconfigure(struct sk_buff *skb, struct genl_info *info)
1740 {
1741 struct nbd_device *nbd = NULL;
1742 struct nbd_config *config;
1743 int index;
1744 int ret = -EINVAL;
1745 bool put_dev = false;
1746
1747 if (!netlink_capable(skb, CAP_SYS_ADMIN))
1748 return -EPERM;
1749
1750 if (!info->attrs[NBD_ATTR_INDEX]) {
1751 printk(KERN_ERR "nbd: must specify a device to reconfigure\n");
1752 return -EINVAL;
1753 }
1754 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1755 mutex_lock(&nbd_index_mutex);
1756 nbd = idr_find(&nbd_index_idr, index);
1757 if (!nbd) {
1758 mutex_unlock(&nbd_index_mutex);
1759 printk(KERN_ERR "nbd: couldn't find a device at index %d\n",
1760 index);
1761 return -EINVAL;
1762 }
1763 if (!refcount_inc_not_zero(&nbd->refs)) {
1764 mutex_unlock(&nbd_index_mutex);
1765 printk(KERN_ERR "nbd: device at index %d is going down\n",
1766 index);
1767 return -EINVAL;
1768 }
1769 mutex_unlock(&nbd_index_mutex);
1770
1771 if (!refcount_inc_not_zero(&nbd->config_refs)) {
1772 dev_err(nbd_to_dev(nbd),
1773 "not configured, cannot reconfigure\n");
1774 nbd_put(nbd);
1775 return -EINVAL;
1776 }
1777
1778 mutex_lock(&nbd->config_lock);
1779 config = nbd->config;
1780 if (!test_bit(NBD_BOUND, &config->runtime_flags) ||
1781 !nbd->task_recv) {
1782 dev_err(nbd_to_dev(nbd),
1783 "not configured, cannot reconfigure\n");
1784 goto out;
1785 }
1786
1787 if (info->attrs[NBD_ATTR_TIMEOUT]) {
1788 u64 timeout = nla_get_u64(info->attrs[NBD_ATTR_TIMEOUT]);
1789 nbd->tag_set.timeout = timeout * HZ;
1790 blk_queue_rq_timeout(nbd->disk->queue, timeout * HZ);
1791 }
1792 if (info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]) {
1793 config->dead_conn_timeout =
1794 nla_get_u64(info->attrs[NBD_ATTR_DEAD_CONN_TIMEOUT]);
1795 config->dead_conn_timeout *= HZ;
1796 }
1797 if (info->attrs[NBD_ATTR_CLIENT_FLAGS]) {
1798 u64 flags = nla_get_u64(info->attrs[NBD_ATTR_CLIENT_FLAGS]);
1799 if (flags & NBD_CFLAG_DESTROY_ON_DISCONNECT) {
1800 if (!test_and_set_bit(NBD_DESTROY_ON_DISCONNECT,
1801 &config->runtime_flags))
1802 put_dev = true;
1803 } else {
1804 if (test_and_clear_bit(NBD_DESTROY_ON_DISCONNECT,
1805 &config->runtime_flags))
1806 refcount_inc(&nbd->refs);
1807 }
1808 }
1809
1810 if (info->attrs[NBD_ATTR_SOCKETS]) {
1811 struct nlattr *attr;
1812 int rem, fd;
1813
1814 nla_for_each_nested(attr, info->attrs[NBD_ATTR_SOCKETS],
1815 rem) {
1816 struct nlattr *socks[NBD_SOCK_MAX+1];
1817
1818 if (nla_type(attr) != NBD_SOCK_ITEM) {
1819 printk(KERN_ERR "nbd: socks must be embedded in a SOCK_ITEM attr\n");
1820 ret = -EINVAL;
1821 goto out;
1822 }
1823 ret = nla_parse_nested(socks, NBD_SOCK_MAX, attr,
1824 nbd_sock_policy, info->extack);
1825 if (ret != 0) {
1826 printk(KERN_ERR "nbd: error processing sock list\n");
1827 ret = -EINVAL;
1828 goto out;
1829 }
1830 if (!socks[NBD_SOCK_FD])
1831 continue;
1832 fd = (int)nla_get_u32(socks[NBD_SOCK_FD]);
1833 ret = nbd_reconnect_socket(nbd, fd);
1834 if (ret) {
1835 if (ret == -ENOSPC)
1836 ret = 0;
1837 goto out;
1838 }
1839 dev_info(nbd_to_dev(nbd), "reconnected socket\n");
1840 }
1841 }
1842 out:
1843 mutex_unlock(&nbd->config_lock);
1844 nbd_config_put(nbd);
1845 nbd_put(nbd);
1846 if (put_dev)
1847 nbd_put(nbd);
1848 return ret;
1849 }
1850
1851 static const struct genl_ops nbd_connect_genl_ops[] = {
1852 {
1853 .cmd = NBD_CMD_CONNECT,
1854 .policy = nbd_attr_policy,
1855 .doit = nbd_genl_connect,
1856 },
1857 {
1858 .cmd = NBD_CMD_DISCONNECT,
1859 .policy = nbd_attr_policy,
1860 .doit = nbd_genl_disconnect,
1861 },
1862 {
1863 .cmd = NBD_CMD_RECONFIGURE,
1864 .policy = nbd_attr_policy,
1865 .doit = nbd_genl_reconfigure,
1866 },
1867 {
1868 .cmd = NBD_CMD_STATUS,
1869 .policy = nbd_attr_policy,
1870 .doit = nbd_genl_status,
1871 },
1872 };
1873
1874 static const struct genl_multicast_group nbd_mcast_grps[] = {
1875 { .name = NBD_GENL_MCAST_GROUP_NAME, },
1876 };
1877
1878 static struct genl_family nbd_genl_family __ro_after_init = {
1879 .hdrsize = 0,
1880 .name = NBD_GENL_FAMILY_NAME,
1881 .version = NBD_GENL_VERSION,
1882 .module = THIS_MODULE,
1883 .ops = nbd_connect_genl_ops,
1884 .n_ops = ARRAY_SIZE(nbd_connect_genl_ops),
1885 .maxattr = NBD_ATTR_MAX,
1886 .mcgrps = nbd_mcast_grps,
1887 .n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
1888 };
1889
1890 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
1891 {
1892 struct nlattr *dev_opt;
1893 u8 connected = 0;
1894 int ret;
1895
1896 /* This is a little racey, but for status it's ok. The
1897 * reason we don't take a ref here is because we can't
1898 * take a ref in the index == -1 case as we would need
1899 * to put under the nbd_index_mutex, which could
1900 * deadlock if we are configured to remove ourselves
1901 * once we're disconnected.
1902 */
1903 if (refcount_read(&nbd->config_refs))
1904 connected = 1;
1905 dev_opt = nla_nest_start(reply, NBD_DEVICE_ITEM);
1906 if (!dev_opt)
1907 return -EMSGSIZE;
1908 ret = nla_put_u32(reply, NBD_DEVICE_INDEX, nbd->index);
1909 if (ret)
1910 return -EMSGSIZE;
1911 ret = nla_put_u8(reply, NBD_DEVICE_CONNECTED,
1912 connected);
1913 if (ret)
1914 return -EMSGSIZE;
1915 nla_nest_end(reply, dev_opt);
1916 return 0;
1917 }
1918
1919 static int status_cb(int id, void *ptr, void *data)
1920 {
1921 struct nbd_device *nbd = ptr;
1922 return populate_nbd_status(nbd, (struct sk_buff *)data);
1923 }
1924
1925 static int nbd_genl_status(struct sk_buff *skb, struct genl_info *info)
1926 {
1927 struct nlattr *dev_list;
1928 struct sk_buff *reply;
1929 void *reply_head;
1930 size_t msg_size;
1931 int index = -1;
1932 int ret = -ENOMEM;
1933
1934 if (info->attrs[NBD_ATTR_INDEX])
1935 index = nla_get_u32(info->attrs[NBD_ATTR_INDEX]);
1936
1937 mutex_lock(&nbd_index_mutex);
1938
1939 msg_size = nla_total_size(nla_attr_size(sizeof(u32)) +
1940 nla_attr_size(sizeof(u8)));
1941 msg_size *= (index == -1) ? nbd_total_devices : 1;
1942
1943 reply = genlmsg_new(msg_size, GFP_KERNEL);
1944 if (!reply)
1945 goto out;
1946 reply_head = genlmsg_put_reply(reply, info, &nbd_genl_family, 0,
1947 NBD_CMD_STATUS);
1948 if (!reply_head) {
1949 nlmsg_free(reply);
1950 goto out;
1951 }
1952
1953 dev_list = nla_nest_start(reply, NBD_ATTR_DEVICE_LIST);
1954 if (index == -1) {
1955 ret = idr_for_each(&nbd_index_idr, &status_cb, reply);
1956 if (ret) {
1957 nlmsg_free(reply);
1958 goto out;
1959 }
1960 } else {
1961 struct nbd_device *nbd;
1962 nbd = idr_find(&nbd_index_idr, index);
1963 if (nbd) {
1964 ret = populate_nbd_status(nbd, reply);
1965 if (ret) {
1966 nlmsg_free(reply);
1967 goto out;
1968 }
1969 }
1970 }
1971 nla_nest_end(reply, dev_list);
1972 genlmsg_end(reply, reply_head);
1973 genlmsg_reply(reply, info);
1974 ret = 0;
1975 out:
1976 mutex_unlock(&nbd_index_mutex);
1977 return ret;
1978 }
1979
1980 static void nbd_connect_reply(struct genl_info *info, int index)
1981 {
1982 struct sk_buff *skb;
1983 void *msg_head;
1984 int ret;
1985
1986 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
1987 if (!skb)
1988 return;
1989 msg_head = genlmsg_put_reply(skb, info, &nbd_genl_family, 0,
1990 NBD_CMD_CONNECT);
1991 if (!msg_head) {
1992 nlmsg_free(skb);
1993 return;
1994 }
1995 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
1996 if (ret) {
1997 nlmsg_free(skb);
1998 return;
1999 }
2000 genlmsg_end(skb, msg_head);
2001 genlmsg_reply(skb, info);
2002 }
2003
2004 static void nbd_mcast_index(int index)
2005 {
2006 struct sk_buff *skb;
2007 void *msg_head;
2008 int ret;
2009
2010 skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
2011 if (!skb)
2012 return;
2013 msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
2014 NBD_CMD_LINK_DEAD);
2015 if (!msg_head) {
2016 nlmsg_free(skb);
2017 return;
2018 }
2019 ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
2020 if (ret) {
2021 nlmsg_free(skb);
2022 return;
2023 }
2024 genlmsg_end(skb, msg_head);
2025 genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
2026 }
2027
2028 static void nbd_dead_link_work(struct work_struct *work)
2029 {
2030 struct link_dead_args *args = container_of(work, struct link_dead_args,
2031 work);
2032 nbd_mcast_index(args->index);
2033 kfree(args);
2034 }
2035
2036 static int __init nbd_init(void)
2037 {
2038 int i;
2039
2040 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
2041
2042 if (max_part < 0) {
2043 printk(KERN_ERR "nbd: max_part must be >= 0\n");
2044 return -EINVAL;
2045 }
2046
2047 part_shift = 0;
2048 if (max_part > 0) {
2049 part_shift = fls(max_part);
2050
2051 /*
2052 * Adjust max_part according to part_shift as it is exported
2053 * to user space so that user can know the max number of
2054 * partition kernel should be able to manage.
2055 *
2056 * Note that -1 is required because partition 0 is reserved
2057 * for the whole disk.
2058 */
2059 max_part = (1UL << part_shift) - 1;
2060 }
2061
2062 if ((1UL << part_shift) > DISK_MAX_PARTS)
2063 return -EINVAL;
2064
2065 if (nbds_max > 1UL << (MINORBITS - part_shift))
2066 return -EINVAL;
2067 recv_workqueue = alloc_workqueue("knbd-recv",
2068 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
2069 if (!recv_workqueue)
2070 return -ENOMEM;
2071
2072 if (register_blkdev(NBD_MAJOR, "nbd")) {
2073 destroy_workqueue(recv_workqueue);
2074 return -EIO;
2075 }
2076
2077 if (genl_register_family(&nbd_genl_family)) {
2078 unregister_blkdev(NBD_MAJOR, "nbd");
2079 destroy_workqueue(recv_workqueue);
2080 return -EINVAL;
2081 }
2082 nbd_dbg_init();
2083
2084 mutex_lock(&nbd_index_mutex);
2085 for (i = 0; i < nbds_max; i++)
2086 nbd_dev_add(i);
2087 mutex_unlock(&nbd_index_mutex);
2088 return 0;
2089 }
2090
2091 static int nbd_exit_cb(int id, void *ptr, void *data)
2092 {
2093 struct list_head *list = (struct list_head *)data;
2094 struct nbd_device *nbd = ptr;
2095
2096 list_add_tail(&nbd->list, list);
2097 return 0;
2098 }
2099
2100 static void __exit nbd_cleanup(void)
2101 {
2102 struct nbd_device *nbd;
2103 LIST_HEAD(del_list);
2104
2105 nbd_dbg_close();
2106
2107 mutex_lock(&nbd_index_mutex);
2108 idr_for_each(&nbd_index_idr, &nbd_exit_cb, &del_list);
2109 mutex_unlock(&nbd_index_mutex);
2110
2111 while (!list_empty(&del_list)) {
2112 nbd = list_first_entry(&del_list, struct nbd_device, list);
2113 list_del_init(&nbd->list);
2114 if (refcount_read(&nbd->refs) != 1)
2115 printk(KERN_ERR "nbd: possibly leaking a device\n");
2116 nbd_put(nbd);
2117 }
2118
2119 idr_destroy(&nbd_index_idr);
2120 genl_unregister_family(&nbd_genl_family);
2121 destroy_workqueue(recv_workqueue);
2122 unregister_blkdev(NBD_MAJOR, "nbd");
2123 }
2124
2125 module_init(nbd_init);
2126 module_exit(nbd_cleanup);
2127
2128 MODULE_DESCRIPTION("Network Block Device");
2129 MODULE_LICENSE("GPL");
2130
2131 module_param(nbds_max, int, 0444);
2132 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
2133 module_param(max_part, int, 0444);
2134 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");
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