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