blob: 9fd06eeb1a17b3880e2ad574f4ca081903a67961 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 *
Pavel Macheka2531292010-07-18 14:27:13 +02007 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
Linus Torvalds1da177e2005-04-16 15:20:36 -07008 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
9 *
Pavel Machekdbf492d2006-06-25 05:47:42 -070010 * This file is released under GPLv2 or later.
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 *
Pavel Machekdbf492d2006-06-25 05:47:42 -070012 * (part of code stolen from loop.c)
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 */
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/fs.h>
22#include <linux/bio.h>
23#include <linux/stat.h>
24#include <linux/errno.h>
25#include <linux/file.h>
26#include <linux/ioctl.h>
Arnd Bergmann2a48fc02010-06-02 14:28:52 +020027#include <linux/mutex.h>
Herbert Xu4b2f0262006-01-06 00:09:47 -080028#include <linux/compiler.h>
29#include <linux/err.h>
30#include <linux/kernel.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090031#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <net/sock.h>
Trond Myklebust91cf45f2007-11-12 18:10:39 -080033#include <linux/net.h>
Laurent Vivier48cf6062008-04-29 01:02:46 -070034#include <linux/kthread.h>
Markus Pargmannb9c495b2015-04-02 10:11:37 +020035#include <linux/types.h>
Markus Pargmann30d53d92015-08-17 08:20:06 +020036#include <linux/debugfs.h>
Josef Bacikfd8383f2016-09-08 12:33:37 -070037#include <linux/blk-mq.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070038
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -080039#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040#include <asm/types.h>
41
42#include <linux/nbd.h>
43
Josef Bacik9561a7a2016-11-22 14:04:40 -050044struct nbd_sock {
45 struct socket *sock;
46 struct mutex tx_lock;
47};
48
Josef Bacik9b4a6ba2016-09-08 12:33:39 -070049#define NBD_TIMEDOUT 0
50#define NBD_DISCONNECT_REQUESTED 1
Josef Bacik9561a7a2016-11-22 14:04:40 -050051#define NBD_DISCONNECTED 2
52#define NBD_RUNNING 3
Josef Bacik9b4a6ba2016-09-08 12:33:39 -070053
Markus Pargmann13e71d62015-04-02 10:11:35 +020054struct nbd_device {
Markus Pargmann22d109c2015-08-17 08:20:09 +020055 u32 flags;
Josef Bacik9b4a6ba2016-09-08 12:33:39 -070056 unsigned long runtime_flags;
Josef Bacik9561a7a2016-11-22 14:04:40 -050057 struct nbd_sock **socks;
Markus Pargmann13e71d62015-04-02 10:11:35 +020058 int magic;
59
Josef Bacikfd8383f2016-09-08 12:33:37 -070060 struct blk_mq_tag_set tag_set;
Markus Pargmann13e71d62015-04-02 10:11:35 +020061
Josef Bacik9561a7a2016-11-22 14:04:40 -050062 struct mutex config_lock;
Markus Pargmann13e71d62015-04-02 10:11:35 +020063 struct gendisk *disk;
Josef Bacik9561a7a2016-11-22 14:04:40 -050064 int num_connections;
65 atomic_t recv_threads;
66 wait_queue_head_t recv_wq;
Josef Bacikef77b512016-12-02 16:19:12 -050067 loff_t blksize;
Markus Pargmannb9c495b2015-04-02 10:11:37 +020068 loff_t bytesize;
Markus Pargmann7e2893a2015-08-17 08:20:00 +020069
Markus Pargmann7e2893a2015-08-17 08:20:00 +020070 struct task_struct *task_recv;
Josef Bacik9561a7a2016-11-22 14:04:40 -050071 struct task_struct *task_setup;
Markus Pargmann30d53d92015-08-17 08:20:06 +020072
73#if IS_ENABLED(CONFIG_DEBUG_FS)
74 struct dentry *dbg_dir;
75#endif
Markus Pargmann13e71d62015-04-02 10:11:35 +020076};
77
Josef Bacikfd8383f2016-09-08 12:33:37 -070078struct nbd_cmd {
79 struct nbd_device *nbd;
Josef Bacik9561a7a2016-11-22 14:04:40 -050080 struct completion send_complete;
Josef Bacikfd8383f2016-09-08 12:33:37 -070081};
82
Markus Pargmann30d53d92015-08-17 08:20:06 +020083#if IS_ENABLED(CONFIG_DEBUG_FS)
84static struct dentry *nbd_dbg_dir;
85#endif
86
87#define nbd_name(nbd) ((nbd)->disk->disk_name)
88
Wanlong Gaof4507162012-03-28 14:42:51 -070089#define NBD_MAGIC 0x68797548
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
Ingo van Lil9c7a4162006-07-01 04:36:36 -070091static unsigned int nbds_max = 16;
Paul Clements20a81432008-02-08 04:21:51 -080092static struct nbd_device *nbd_dev;
Laurent Vivierd71a6d72008-04-29 01:02:51 -070093static int max_part;
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
Markus Pargmannd18509f2015-04-02 10:11:38 +020095static inline struct device *nbd_to_dev(struct nbd_device *nbd)
Linus Torvalds1da177e2005-04-16 15:20:36 -070096{
Markus Pargmannd18509f2015-04-02 10:11:38 +020097 return disk_to_dev(nbd->disk);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098}
99
Markus Pargmann37091fd2015-07-27 07:36:49 +0200100static bool nbd_is_connected(struct nbd_device *nbd)
101{
102 return !!nbd->task_recv;
103}
104
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105static const char *nbdcmd_to_ascii(int cmd)
106{
107 switch (cmd) {
108 case NBD_CMD_READ: return "read";
109 case NBD_CMD_WRITE: return "write";
110 case NBD_CMD_DISC: return "disconnect";
Alex Bligh75f187a2013-02-27 17:05:23 -0800111 case NBD_CMD_FLUSH: return "flush";
Paul Clementsa336d292012-10-04 17:16:18 -0700112 case NBD_CMD_TRIM: return "trim/discard";
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 }
114 return "invalid";
115}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116
Markus Pargmann37091fd2015-07-27 07:36:49 +0200117static int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev)
118{
119 bdev->bd_inode->i_size = 0;
120 set_capacity(nbd->disk, 0);
121 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
122
123 return 0;
124}
125
126static void nbd_size_update(struct nbd_device *nbd, struct block_device *bdev)
127{
128 if (!nbd_is_connected(nbd))
129 return;
130
131 bdev->bd_inode->i_size = nbd->bytesize;
132 set_capacity(nbd->disk, nbd->bytesize >> 9);
133 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
134}
135
136static int nbd_size_set(struct nbd_device *nbd, struct block_device *bdev,
Josef Bacikef77b512016-12-02 16:19:12 -0500137 loff_t blocksize, loff_t nr_blocks)
Markus Pargmann37091fd2015-07-27 07:36:49 +0200138{
139 int ret;
140
141 ret = set_blocksize(bdev, blocksize);
142 if (ret)
143 return ret;
144
145 nbd->blksize = blocksize;
Josef Bacikef77b512016-12-02 16:19:12 -0500146 nbd->bytesize = blocksize * nr_blocks;
Markus Pargmann37091fd2015-07-27 07:36:49 +0200147
148 nbd_size_update(nbd, bdev);
149
150 return 0;
151}
152
Josef Bacikfd8383f2016-09-08 12:33:37 -0700153static void nbd_end_request(struct nbd_cmd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154{
Josef Bacikfd8383f2016-09-08 12:33:37 -0700155 struct nbd_device *nbd = cmd->nbd;
156 struct request *req = blk_mq_rq_from_pdu(cmd);
Kiyoshi Ueda097c94a2007-12-11 17:44:06 -0500157 int error = req->errors ? -EIO : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158
Josef Bacikfd8383f2016-09-08 12:33:37 -0700159 dev_dbg(nbd_to_dev(nbd), "request %p: %s\n", cmd,
Markus Pargmannd18509f2015-04-02 10:11:38 +0200160 error ? "failed" : "done");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
Josef Bacikfd8383f2016-09-08 12:33:37 -0700162 blk_mq_complete_request(req, error);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163}
164
Markus Pargmanne018e752015-04-02 10:11:39 +0200165/*
166 * Forcibly shutdown the socket causing all listeners to error
167 */
Markus Pargmann36e47be2015-08-17 08:20:01 +0200168static void sock_shutdown(struct nbd_device *nbd)
Paul Clements7fdfd402007-10-16 23:27:37 -0700169{
Josef Bacik9561a7a2016-11-22 14:04:40 -0500170 int i;
Josef Bacikc2611892016-09-08 12:33:38 -0700171
Josef Bacik9561a7a2016-11-22 14:04:40 -0500172 if (nbd->num_connections == 0)
Markus Pargmann260bbce2015-08-17 08:20:02 +0200173 return;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500174 if (test_and_set_bit(NBD_DISCONNECTED, &nbd->runtime_flags))
175 return;
176
177 for (i = 0; i < nbd->num_connections; i++) {
178 struct nbd_sock *nsock = nbd->socks[i];
179 mutex_lock(&nsock->tx_lock);
180 kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
181 mutex_unlock(&nsock->tx_lock);
Markus Pargmann23272a672015-10-29 11:51:16 +0100182 }
Josef Bacik9561a7a2016-11-22 14:04:40 -0500183 dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
Paul Clements7fdfd402007-10-16 23:27:37 -0700184}
185
Josef Bacik0eadf372016-09-08 12:33:40 -0700186static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
187 bool reserved)
Paul Clements7fdfd402007-10-16 23:27:37 -0700188{
Josef Bacik0eadf372016-09-08 12:33:40 -0700189 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);
190 struct nbd_device *nbd = cmd->nbd;
Paul Clements7fdfd402007-10-16 23:27:37 -0700191
Markus Pargmann23272a672015-10-29 11:51:16 +0100192 dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down connection\n");
Josef Bacik9561a7a2016-11-22 14:04:40 -0500193 set_bit(NBD_TIMEDOUT, &nbd->runtime_flags);
194 req->errors++;
195
196 /*
197 * If our disconnect packet times out then we're already holding the
198 * config_lock and could deadlock here, so just set an error and return,
199 * we'll handle shutting everything down later.
200 */
201 if (req->cmd_type == REQ_TYPE_DRV_PRIV)
202 return BLK_EH_HANDLED;
203 mutex_lock(&nbd->config_lock);
204 sock_shutdown(nbd);
205 mutex_unlock(&nbd->config_lock);
Josef Bacik0eadf372016-09-08 12:33:40 -0700206 return BLK_EH_HANDLED;
Paul Clements7fdfd402007-10-16 23:27:37 -0700207}
208
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209/*
210 * Send or receive packet.
211 */
Josef Bacik9561a7a2016-11-22 14:04:40 -0500212static int sock_xmit(struct nbd_device *nbd, int index, int send, void *buf,
213 int size, int msg_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214{
Josef Bacik9561a7a2016-11-22 14:04:40 -0500215 struct socket *sock = nbd->socks[index]->sock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 int result;
217 struct msghdr msg;
218 struct kvec iov;
Mel Gorman7f338fe2012-07-31 16:44:32 -0700219 unsigned long pflags = current->flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220
Mike Snitzerffc41cf2008-04-02 13:04:47 -0700221 if (unlikely(!sock)) {
Josef Bacika897b662016-12-05 16:20:29 -0500222 dev_err_ratelimited(disk_to_dev(nbd->disk),
WANG Cong7f1b90f2011-08-19 14:48:22 +0200223 "Attempted %s on closed socket in sock_xmit\n",
224 (send ? "send" : "recv"));
Mike Snitzerffc41cf2008-04-02 13:04:47 -0700225 return -EINVAL;
226 }
227
Mel Gorman7f338fe2012-07-31 16:44:32 -0700228 current->flags |= PF_MEMALLOC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229 do {
Mel Gorman7f338fe2012-07-31 16:44:32 -0700230 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231 iov.iov_base = buf;
232 iov.iov_len = size;
233 msg.msg_name = NULL;
234 msg.msg_namelen = 0;
235 msg.msg_control = NULL;
236 msg.msg_controllen = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
238
Markus Pargmann7e2893a2015-08-17 08:20:00 +0200239 if (send)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 result = kernel_sendmsg(sock, &msg, &iov, 1, size);
Markus Pargmann7e2893a2015-08-17 08:20:00 +0200241 else
Namhyung Kim35fbf5b2011-05-28 14:44:46 +0200242 result = kernel_recvmsg(sock, &msg, &iov, 1, size,
243 msg.msg_flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 if (result <= 0) {
246 if (result == 0)
247 result = -EPIPE; /* short read */
248 break;
249 }
250 size -= result;
251 buf += result;
252 } while (size > 0);
253
Mel Gorman7f338fe2012-07-31 16:44:32 -0700254 tsk_restore_flags(current, pflags, PF_MEMALLOC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255
256 return result;
257}
258
Josef Bacik9561a7a2016-11-22 14:04:40 -0500259static inline int sock_send_bvec(struct nbd_device *nbd, int index,
260 struct bio_vec *bvec, int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261{
262 int result;
263 void *kaddr = kmap(bvec->bv_page);
Josef Bacik9561a7a2016-11-22 14:04:40 -0500264 result = sock_xmit(nbd, index, 1, kaddr + bvec->bv_offset,
Wanlong Gaof4507162012-03-28 14:42:51 -0700265 bvec->bv_len, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 kunmap(bvec->bv_page);
267 return result;
268}
269
Paul Clements7fdfd402007-10-16 23:27:37 -0700270/* always call with the tx_lock held */
Josef Bacik9561a7a2016-11-22 14:04:40 -0500271static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272{
Josef Bacikfd8383f2016-09-08 12:33:37 -0700273 struct request *req = blk_mq_rq_from_pdu(cmd);
Josef Bacikd61b7f92017-01-19 16:08:49 -0500274 int result;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 struct nbd_request request;
Tejun Heo1011c1b2009-05-07 22:24:45 +0900276 unsigned long size = blk_rq_bytes(req);
Jens Axboe429a7872016-11-17 12:30:37 -0700277 struct bio *bio;
Christoph Hellwig9dc6c802015-04-17 22:37:21 +0200278 u32 type;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500279 u32 tag = blk_mq_unique_tag(req);
Christoph Hellwig9dc6c802015-04-17 22:37:21 +0200280
Josef Bacik9561a7a2016-11-22 14:04:40 -0500281 if (req_op(req) == REQ_OP_DISCARD)
Christoph Hellwig9dc6c802015-04-17 22:37:21 +0200282 type = NBD_CMD_TRIM;
Mike Christie3a5e02c2016-06-05 14:32:23 -0500283 else if (req_op(req) == REQ_OP_FLUSH)
Christoph Hellwig9dc6c802015-04-17 22:37:21 +0200284 type = NBD_CMD_FLUSH;
285 else if (rq_data_dir(req) == WRITE)
286 type = NBD_CMD_WRITE;
287 else
288 type = NBD_CMD_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289
Hani Benhabiles04cfac42014-06-06 14:38:30 -0700290 memset(&request, 0, sizeof(request));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291 request.magic = htonl(NBD_REQUEST_MAGIC);
Christoph Hellwig9dc6c802015-04-17 22:37:21 +0200292 request.type = htonl(type);
Josef Bacik9561a7a2016-11-22 14:04:40 -0500293 if (type != NBD_CMD_FLUSH) {
Alex Bligh75f187a2013-02-27 17:05:23 -0800294 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
295 request.len = htonl(size);
296 }
Josef Bacik9561a7a2016-11-22 14:04:40 -0500297 memcpy(request.handle, &tag, sizeof(tag));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298
Markus Pargmannd18509f2015-04-02 10:11:38 +0200299 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
Josef Bacikfd8383f2016-09-08 12:33:37 -0700300 cmd, nbdcmd_to_ascii(type),
Markus Pargmannd18509f2015-04-02 10:11:38 +0200301 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
Josef Bacik9561a7a2016-11-22 14:04:40 -0500302 result = sock_xmit(nbd, index, 1, &request, sizeof(request),
Christoph Hellwig9dc6c802015-04-17 22:37:21 +0200303 (type == NBD_CMD_WRITE) ? MSG_MORE : 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 if (result <= 0) {
Josef Bacika897b662016-12-05 16:20:29 -0500305 dev_err_ratelimited(disk_to_dev(nbd->disk),
WANG Cong7f1b90f2011-08-19 14:48:22 +0200306 "Send control failed (result %d)\n", result);
Markus Pargmanndab53132015-04-02 10:11:40 +0200307 return -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308 }
309
Jens Axboe429a7872016-11-17 12:30:37 -0700310 if (type != NBD_CMD_WRITE)
311 return 0;
312
Jens Axboe429a7872016-11-17 12:30:37 -0700313 bio = req->bio;
314 while (bio) {
315 struct bio *next = bio->bi_next;
316 struct bvec_iter iter;
Kent Overstreet79886132013-11-23 17:19:00 -0800317 struct bio_vec bvec;
Jens Axboe429a7872016-11-17 12:30:37 -0700318
319 bio_for_each_segment(bvec, bio, iter) {
320 bool is_last = !next && bio_iter_last(bvec, iter);
Josef Bacikd61b7f92017-01-19 16:08:49 -0500321 int flags = is_last ? 0 : MSG_MORE;
Jens Axboe429a7872016-11-17 12:30:37 -0700322
Markus Pargmannd18509f2015-04-02 10:11:38 +0200323 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
Josef Bacikfd8383f2016-09-08 12:33:37 -0700324 cmd, bvec.bv_len);
Josef Bacik9561a7a2016-11-22 14:04:40 -0500325 result = sock_send_bvec(nbd, index, &bvec, flags);
Jens Axboe6c92e692007-08-16 13:43:12 +0200326 if (result <= 0) {
Wanlong Gaof4507162012-03-28 14:42:51 -0700327 dev_err(disk_to_dev(nbd->disk),
WANG Cong7f1b90f2011-08-19 14:48:22 +0200328 "Send data failed (result %d)\n",
329 result);
Markus Pargmanndab53132015-04-02 10:11:40 +0200330 return -EIO;
Jens Axboe6c92e692007-08-16 13:43:12 +0200331 }
Jens Axboe429a7872016-11-17 12:30:37 -0700332 /*
333 * The completion might already have come in,
334 * so break for the last one instead of letting
335 * the iterator do it. This prevents use-after-free
336 * of the bio.
337 */
338 if (is_last)
339 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700340 }
Jens Axboe429a7872016-11-17 12:30:37 -0700341 bio = next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344}
345
Josef Bacik9561a7a2016-11-22 14:04:40 -0500346static inline int sock_recv_bvec(struct nbd_device *nbd, int index,
347 struct bio_vec *bvec)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348{
349 int result;
350 void *kaddr = kmap(bvec->bv_page);
Josef Bacik9561a7a2016-11-22 14:04:40 -0500351 result = sock_xmit(nbd, index, 0, kaddr + bvec->bv_offset,
352 bvec->bv_len, MSG_WAITALL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 kunmap(bvec->bv_page);
354 return result;
355}
356
357/* NULL returned = something went wrong, inform userspace */
Josef Bacik9561a7a2016-11-22 14:04:40 -0500358static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359{
360 int result;
361 struct nbd_reply reply;
Josef Bacikfd8383f2016-09-08 12:33:37 -0700362 struct nbd_cmd *cmd;
363 struct request *req = NULL;
364 u16 hwq;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500365 u32 tag;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366
367 reply.magic = 0;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500368 result = sock_xmit(nbd, index, 0, &reply, sizeof(reply), MSG_WAITALL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 if (result <= 0) {
Josef Bacik9561a7a2016-11-22 14:04:40 -0500370 if (!test_bit(NBD_DISCONNECTED, &nbd->runtime_flags) &&
371 !test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
372 dev_err(disk_to_dev(nbd->disk),
373 "Receive control failed (result %d)\n", result);
Markus Pargmann19391832015-08-17 08:20:03 +0200374 return ERR_PTR(result);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 }
Michal Feixe4b57e02006-07-30 03:03:31 -0700376
377 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
Wanlong Gaof4507162012-03-28 14:42:51 -0700378 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
Michal Feixe4b57e02006-07-30 03:03:31 -0700379 (unsigned long)ntohl(reply.magic));
Markus Pargmann19391832015-08-17 08:20:03 +0200380 return ERR_PTR(-EPROTO);
Michal Feixe4b57e02006-07-30 03:03:31 -0700381 }
382
Josef Bacik9561a7a2016-11-22 14:04:40 -0500383 memcpy(&tag, reply.handle, sizeof(u32));
Herbert Xu4b2f0262006-01-06 00:09:47 -0800384
Josef Bacikfd8383f2016-09-08 12:33:37 -0700385 hwq = blk_mq_unique_tag_to_hwq(tag);
386 if (hwq < nbd->tag_set.nr_hw_queues)
387 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
388 blk_mq_unique_tag_to_tag(tag));
389 if (!req || !blk_mq_request_started(req)) {
390 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
391 tag, req);
392 return ERR_PTR(-ENOENT);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 }
Josef Bacikfd8383f2016-09-08 12:33:37 -0700394 cmd = blk_mq_rq_to_pdu(req);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 if (ntohl(reply.error)) {
Wanlong Gaof4507162012-03-28 14:42:51 -0700396 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
WANG Cong7f1b90f2011-08-19 14:48:22 +0200397 ntohl(reply.error));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 req->errors++;
Josef Bacikfd8383f2016-09-08 12:33:37 -0700399 return cmd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 }
401
Josef Bacikfd8383f2016-09-08 12:33:37 -0700402 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd);
Christoph Hellwig9dc6c802015-04-17 22:37:21 +0200403 if (rq_data_dir(req) != WRITE) {
NeilBrown5705f702007-09-25 12:35:59 +0200404 struct req_iterator iter;
Kent Overstreet79886132013-11-23 17:19:00 -0800405 struct bio_vec bvec;
NeilBrown5705f702007-09-25 12:35:59 +0200406
407 rq_for_each_segment(bvec, req, iter) {
Josef Bacik9561a7a2016-11-22 14:04:40 -0500408 result = sock_recv_bvec(nbd, index, &bvec);
Jens Axboe6c92e692007-08-16 13:43:12 +0200409 if (result <= 0) {
Wanlong Gaof4507162012-03-28 14:42:51 -0700410 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
WANG Cong7f1b90f2011-08-19 14:48:22 +0200411 result);
Jens Axboe6c92e692007-08-16 13:43:12 +0200412 req->errors++;
Josef Bacikfd8383f2016-09-08 12:33:37 -0700413 return cmd;
Jens Axboe6c92e692007-08-16 13:43:12 +0200414 }
Markus Pargmannd18509f2015-04-02 10:11:38 +0200415 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
Josef Bacikfd8383f2016-09-08 12:33:37 -0700416 cmd, bvec.bv_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 }
Josef Bacik9561a7a2016-11-22 14:04:40 -0500418 } else {
419 /* See the comment in nbd_queue_rq. */
420 wait_for_completion(&cmd->send_complete);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 }
Josef Bacikfd8383f2016-09-08 12:33:37 -0700422 return cmd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423}
424
Kay Sieversedfaa7c2007-05-21 22:08:01 +0200425static ssize_t pid_show(struct device *dev,
426 struct device_attribute *attr, char *buf)
Paul Clements6b39bb62006-12-06 20:40:53 -0800427{
Kay Sieversedfaa7c2007-05-21 22:08:01 +0200428 struct gendisk *disk = dev_to_disk(dev);
Markus Pargmann6521d392015-08-17 08:20:05 +0200429 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
Kay Sieversedfaa7c2007-05-21 22:08:01 +0200430
Markus Pargmann6521d392015-08-17 08:20:05 +0200431 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
Paul Clements6b39bb62006-12-06 20:40:53 -0800432}
433
Kay Sieversedfaa7c2007-05-21 22:08:01 +0200434static struct device_attribute pid_attr = {
Parag Warudkar01e8ef12008-10-18 20:28:50 -0700435 .attr = { .name = "pid", .mode = S_IRUGO},
Paul Clements6b39bb62006-12-06 20:40:53 -0800436 .show = pid_show,
437};
438
Josef Bacik9561a7a2016-11-22 14:04:40 -0500439struct recv_thread_args {
440 struct work_struct work;
441 struct nbd_device *nbd;
442 int index;
443};
444
445static void recv_work(struct work_struct *work)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446{
Josef Bacik9561a7a2016-11-22 14:04:40 -0500447 struct recv_thread_args *args = container_of(work,
448 struct recv_thread_args,
449 work);
450 struct nbd_device *nbd = args->nbd;
Josef Bacikfd8383f2016-09-08 12:33:37 -0700451 struct nbd_cmd *cmd;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500452 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453
Wanlong Gaof4507162012-03-28 14:42:51 -0700454 BUG_ON(nbd->magic != NBD_MAGIC);
Markus Pargmann19391832015-08-17 08:20:03 +0200455 while (1) {
Josef Bacik9561a7a2016-11-22 14:04:40 -0500456 cmd = nbd_read_stat(nbd, args->index);
Josef Bacikfd8383f2016-09-08 12:33:37 -0700457 if (IS_ERR(cmd)) {
458 ret = PTR_ERR(cmd);
Markus Pargmann19391832015-08-17 08:20:03 +0200459 break;
460 }
461
Josef Bacikfd8383f2016-09-08 12:33:37 -0700462 nbd_end_request(cmd);
Markus Pargmann19391832015-08-17 08:20:03 +0200463 }
Paul Clements6b39bb62006-12-06 20:40:53 -0800464
Josef Bacik9561a7a2016-11-22 14:04:40 -0500465 /*
466 * We got an error, shut everybody down if this wasn't the result of a
467 * disconnect request.
468 */
469 if (ret && !test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
470 sock_shutdown(nbd);
471 atomic_dec(&nbd->recv_threads);
472 wake_up(&nbd->recv_wq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473}
474
Josef Bacikfd8383f2016-09-08 12:33:37 -0700475static void nbd_clear_req(struct request *req, void *data, bool reserved)
476{
477 struct nbd_cmd *cmd;
478
479 if (!blk_mq_request_started(req))
480 return;
481 cmd = blk_mq_rq_to_pdu(req);
482 req->errors++;
483 nbd_end_request(cmd);
484}
485
Wanlong Gaof4507162012-03-28 14:42:51 -0700486static void nbd_clear_que(struct nbd_device *nbd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487{
Wanlong Gaof4507162012-03-28 14:42:51 -0700488 BUG_ON(nbd->magic != NBD_MAGIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489
Josef Bacikfd8383f2016-09-08 12:33:37 -0700490 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
Markus Pargmanne78273c2015-08-17 08:20:04 +0200491 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492}
493
Paul Clements7fdfd402007-10-16 23:27:37 -0700494
Josef Bacik9561a7a2016-11-22 14:04:40 -0500495static void nbd_handle_cmd(struct nbd_cmd *cmd, int index)
Laurent Vivier48cf6062008-04-29 01:02:46 -0700496{
Josef Bacikfd8383f2016-09-08 12:33:37 -0700497 struct request *req = blk_mq_rq_from_pdu(cmd);
498 struct nbd_device *nbd = cmd->nbd;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500499 struct nbd_sock *nsock;
Josef Bacikfd8383f2016-09-08 12:33:37 -0700500
Josef Bacik9561a7a2016-11-22 14:04:40 -0500501 if (index >= nbd->num_connections) {
Josef Bacika897b662016-12-05 16:20:29 -0500502 dev_err_ratelimited(disk_to_dev(nbd->disk),
503 "Attempted send on invalid socket\n");
Josef Bacik9561a7a2016-11-22 14:04:40 -0500504 goto error_out;
505 }
506
507 if (test_bit(NBD_DISCONNECTED, &nbd->runtime_flags)) {
Josef Bacika897b662016-12-05 16:20:29 -0500508 dev_err_ratelimited(disk_to_dev(nbd->disk),
509 "Attempted send on closed socket\n");
Josef Bacik9561a7a2016-11-22 14:04:40 -0500510 goto error_out;
511 }
512
513 if (req->cmd_type != REQ_TYPE_FS &&
514 req->cmd_type != REQ_TYPE_DRV_PRIV)
Laurent Vivier48cf6062008-04-29 01:02:46 -0700515 goto error_out;
516
Josef Bacik9561a7a2016-11-22 14:04:40 -0500517 if (req->cmd_type == REQ_TYPE_FS &&
518 rq_data_dir(req) == WRITE &&
Christoph Hellwig9dc6c802015-04-17 22:37:21 +0200519 (nbd->flags & NBD_FLAG_READ_ONLY)) {
Josef Bacika897b662016-12-05 16:20:29 -0500520 dev_err_ratelimited(disk_to_dev(nbd->disk),
521 "Write on read-only\n");
Christoph Hellwig9dc6c802015-04-17 22:37:21 +0200522 goto error_out;
Alex Bligh75f187a2013-02-27 17:05:23 -0800523 }
524
Laurent Vivier48cf6062008-04-29 01:02:46 -0700525 req->errors = 0;
526
Josef Bacik9561a7a2016-11-22 14:04:40 -0500527 nsock = nbd->socks[index];
528 mutex_lock(&nsock->tx_lock);
529 if (unlikely(!nsock->sock)) {
530 mutex_unlock(&nsock->tx_lock);
Josef Bacika897b662016-12-05 16:20:29 -0500531 dev_err_ratelimited(disk_to_dev(nbd->disk),
532 "Attempted send on closed socket\n");
Pavel Machek15746fc2009-04-02 16:58:42 -0700533 goto error_out;
Laurent Vivier48cf6062008-04-29 01:02:46 -0700534 }
535
Josef Bacik9561a7a2016-11-22 14:04:40 -0500536 if (nbd_send_cmd(nbd, cmd, index) != 0) {
Josef Bacika897b662016-12-05 16:20:29 -0500537 dev_err_ratelimited(disk_to_dev(nbd->disk),
538 "Request send failed\n");
Laurent Vivier48cf6062008-04-29 01:02:46 -0700539 req->errors++;
Josef Bacikfd8383f2016-09-08 12:33:37 -0700540 nbd_end_request(cmd);
Laurent Vivier48cf6062008-04-29 01:02:46 -0700541 }
542
Josef Bacik9561a7a2016-11-22 14:04:40 -0500543 mutex_unlock(&nsock->tx_lock);
Laurent Vivier48cf6062008-04-29 01:02:46 -0700544
545 return;
546
547error_out:
548 req->errors++;
Josef Bacikfd8383f2016-09-08 12:33:37 -0700549 nbd_end_request(cmd);
Laurent Vivier48cf6062008-04-29 01:02:46 -0700550}
551
Josef Bacikfd8383f2016-09-08 12:33:37 -0700552static int nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
553 const struct blk_mq_queue_data *bd)
Laurent Vivier48cf6062008-04-29 01:02:46 -0700554{
Josef Bacikfd8383f2016-09-08 12:33:37 -0700555 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
Laurent Vivier48cf6062008-04-29 01:02:46 -0700556
Josef Bacik9561a7a2016-11-22 14:04:40 -0500557 /*
558 * Since we look at the bio's to send the request over the network we
559 * need to make sure the completion work doesn't mark this request done
560 * before we are done doing our send. This keeps us from dereferencing
561 * freed data if we have particularly fast completions (ie we get the
562 * completion before we exit sock_xmit on the last bvec) or in the case
563 * that the server is misbehaving (or there was an error) before we're
564 * done sending everything over the wire.
565 */
566 init_completion(&cmd->send_complete);
Josef Bacikfd8383f2016-09-08 12:33:37 -0700567 blk_mq_start_request(bd->rq);
Josef Bacik9561a7a2016-11-22 14:04:40 -0500568 nbd_handle_cmd(cmd, hctx->queue_num);
569 complete(&cmd->send_complete);
570
Josef Bacikfd8383f2016-09-08 12:33:37 -0700571 return BLK_MQ_RQ_QUEUE_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572}
573
Josef Bacik9561a7a2016-11-22 14:04:40 -0500574static int nbd_add_socket(struct nbd_device *nbd, struct socket *sock)
Markus Pargmann23272a672015-10-29 11:51:16 +0100575{
Josef Bacik9561a7a2016-11-22 14:04:40 -0500576 struct nbd_sock **socks;
577 struct nbd_sock *nsock;
Markus Pargmann23272a672015-10-29 11:51:16 +0100578
Josef Bacik9561a7a2016-11-22 14:04:40 -0500579 if (!nbd->task_setup)
580 nbd->task_setup = current;
581 if (nbd->task_setup != current) {
582 dev_err(disk_to_dev(nbd->disk),
583 "Device being setup by another task");
584 return -EINVAL;
Markus Pargmann23272a672015-10-29 11:51:16 +0100585 }
586
Josef Bacik9561a7a2016-11-22 14:04:40 -0500587 socks = krealloc(nbd->socks, (nbd->num_connections + 1) *
588 sizeof(struct nbd_sock *), GFP_KERNEL);
589 if (!socks)
590 return -ENOMEM;
591 nsock = kzalloc(sizeof(struct nbd_sock), GFP_KERNEL);
592 if (!nsock)
593 return -ENOMEM;
Markus Pargmann23272a672015-10-29 11:51:16 +0100594
Josef Bacik9561a7a2016-11-22 14:04:40 -0500595 nbd->socks = socks;
Markus Pargmann23272a672015-10-29 11:51:16 +0100596
Josef Bacik9561a7a2016-11-22 14:04:40 -0500597 mutex_init(&nsock->tx_lock);
598 nsock->sock = sock;
599 socks[nbd->num_connections++] = nsock;
600
601 return 0;
Markus Pargmann23272a672015-10-29 11:51:16 +0100602}
603
Markus Pargmann0e4f0f62015-10-29 12:04:51 +0100604/* Reset all properties of an NBD device */
605static void nbd_reset(struct nbd_device *nbd)
606{
Josef Bacik9561a7a2016-11-22 14:04:40 -0500607 int i;
608
609 for (i = 0; i < nbd->num_connections; i++)
610 kfree(nbd->socks[i]);
611 kfree(nbd->socks);
612 nbd->socks = NULL;
Josef Bacik9b4a6ba2016-09-08 12:33:39 -0700613 nbd->runtime_flags = 0;
Markus Pargmann0e4f0f62015-10-29 12:04:51 +0100614 nbd->blksize = 1024;
615 nbd->bytesize = 0;
616 set_capacity(nbd->disk, 0);
617 nbd->flags = 0;
Josef Bacik0eadf372016-09-08 12:33:40 -0700618 nbd->tag_set.timeout = 0;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500619 nbd->num_connections = 0;
620 nbd->task_setup = NULL;
Markus Pargmann0e4f0f62015-10-29 12:04:51 +0100621 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
Markus Pargmann0e4f0f62015-10-29 12:04:51 +0100622}
623
624static void nbd_bdev_reset(struct block_device *bdev)
625{
626 set_device_ro(bdev, false);
627 bdev->bd_inode->i_size = 0;
628 if (max_part > 0) {
629 blkdev_reread_part(bdev);
630 bdev->bd_invalidated = 1;
631 }
632}
633
Markus Pargmannd02cf532015-10-29 12:06:15 +0100634static void nbd_parse_flags(struct nbd_device *nbd, struct block_device *bdev)
635{
636 if (nbd->flags & NBD_FLAG_READ_ONLY)
637 set_device_ro(bdev, true);
638 if (nbd->flags & NBD_FLAG_SEND_TRIM)
639 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
640 if (nbd->flags & NBD_FLAG_SEND_FLUSH)
Jens Axboeaafb1ee2016-03-30 10:10:53 -0600641 blk_queue_write_cache(nbd->disk->queue, true, false);
Markus Pargmannd02cf532015-10-29 12:06:15 +0100642 else
Jens Axboeaafb1ee2016-03-30 10:10:53 -0600643 blk_queue_write_cache(nbd->disk->queue, false, false);
Markus Pargmannd02cf532015-10-29 12:06:15 +0100644}
645
Josef Bacik9561a7a2016-11-22 14:04:40 -0500646static void send_disconnects(struct nbd_device *nbd)
647{
648 struct nbd_request request = {};
649 int i, ret;
650
651 request.magic = htonl(NBD_REQUEST_MAGIC);
652 request.type = htonl(NBD_CMD_DISC);
653
654 for (i = 0; i < nbd->num_connections; i++) {
655 ret = sock_xmit(nbd, i, 1, &request, sizeof(request), 0);
656 if (ret <= 0)
657 dev_err(disk_to_dev(nbd->disk),
658 "Send disconnect failed %d\n", ret);
659 }
660}
661
Markus Pargmann30d53d92015-08-17 08:20:06 +0200662static int nbd_dev_dbg_init(struct nbd_device *nbd);
663static void nbd_dev_dbg_close(struct nbd_device *nbd);
664
Josef Bacik9561a7a2016-11-22 14:04:40 -0500665/* Must be called with config_lock held */
Wanlong Gaof4507162012-03-28 14:42:51 -0700666static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
Pavel Machek1a2ad212009-04-02 16:58:41 -0700667 unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 switch (cmd) {
Pavel Machek1a2ad212009-04-02 16:58:41 -0700670 case NBD_DISCONNECT: {
Wanlong Gaof4507162012-03-28 14:42:51 -0700671 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
Josef Bacik9561a7a2016-11-22 14:04:40 -0500672 if (!nbd->socks)
Paolo Bonzini3a2d63f82013-02-27 17:05:25 -0800673 return -EINVAL;
Pavel Machek1a2ad212009-04-02 16:58:41 -0700674
Josef Bacik9561a7a2016-11-22 14:04:40 -0500675 mutex_unlock(&nbd->config_lock);
Paolo Bonzini3a2d63f82013-02-27 17:05:25 -0800676 fsync_bdev(bdev);
Josef Bacik9561a7a2016-11-22 14:04:40 -0500677 mutex_lock(&nbd->config_lock);
Paolo Bonzini3a2d63f82013-02-27 17:05:25 -0800678
679 /* Check again after getting mutex back. */
Josef Bacik9561a7a2016-11-22 14:04:40 -0500680 if (!nbd->socks)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 return -EINVAL;
Paolo Bonzini3a2d63f82013-02-27 17:05:25 -0800682
Josef Bacik9561a7a2016-11-22 14:04:40 -0500683 if (!test_and_set_bit(NBD_DISCONNECT_REQUESTED,
684 &nbd->runtime_flags))
685 send_disconnects(nbd);
Paul Clementsc378f702013-07-03 15:09:04 -0700686 return 0;
Pavel Machek1a2ad212009-04-02 16:58:41 -0700687 }
Josef Bacik9561a7a2016-11-22 14:04:40 -0500688
Markus Pargmann23272a672015-10-29 11:51:16 +0100689 case NBD_CLEAR_SOCK:
690 sock_shutdown(nbd);
Wanlong Gaof4507162012-03-28 14:42:51 -0700691 nbd_clear_que(nbd);
Paolo Bonzini3a2d63f82013-02-27 17:05:25 -0800692 kill_bdev(bdev);
Josef Bacik9561a7a2016-11-22 14:04:40 -0500693 nbd_bdev_reset(bdev);
694 /*
695 * We want to give the run thread a chance to wait for everybody
696 * to clean up and then do it's own cleanup.
697 */
698 if (!test_bit(NBD_RUNNING, &nbd->runtime_flags)) {
699 int i;
700
701 for (i = 0; i < nbd->num_connections; i++)
702 kfree(nbd->socks[i]);
703 kfree(nbd->socks);
704 nbd->socks = NULL;
705 nbd->num_connections = 0;
Josef Bacik20032ec2016-12-08 09:52:35 -0500706 nbd->task_setup = NULL;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500707 }
Pavel Machek1a2ad212009-04-02 16:58:41 -0700708 return 0;
Pavel Machek1a2ad212009-04-02 16:58:41 -0700709
710 case NBD_SET_SOCK: {
Al Viroe2511572014-03-05 20:41:36 -0500711 int err;
Markus Pargmann23272a672015-10-29 11:51:16 +0100712 struct socket *sock = sockfd_lookup(arg, &err);
713
714 if (!sock)
715 return err;
716
Josef Bacik9561a7a2016-11-22 14:04:40 -0500717 err = nbd_add_socket(nbd, sock);
Markus Pargmann23272a672015-10-29 11:51:16 +0100718 if (!err && max_part)
719 bdev->bd_invalidated = 1;
720
721 return err;
Pavel Machek1a2ad212009-04-02 16:58:41 -0700722 }
723
Markus Pargmann37091fd2015-07-27 07:36:49 +0200724 case NBD_SET_BLKSIZE: {
Arnd Bergmann5e454c62016-03-05 00:49:31 +0100725 loff_t bsize = div_s64(nbd->bytesize, arg);
Markus Pargmann37091fd2015-07-27 07:36:49 +0200726
727 return nbd_size_set(nbd, bdev, arg, bsize);
728 }
Pavel Machek1a2ad212009-04-02 16:58:41 -0700729
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 case NBD_SET_SIZE:
Markus Pargmann37091fd2015-07-27 07:36:49 +0200731 return nbd_size_set(nbd, bdev, nbd->blksize,
Jens Axboee88f72c2016-12-03 12:08:03 -0700732 div_s64(arg, nbd->blksize));
Markus Pargmann37091fd2015-07-27 07:36:49 +0200733
734 case NBD_SET_SIZE_BLOCKS:
735 return nbd_size_set(nbd, bdev, nbd->blksize, arg);
Pavel Machek1a2ad212009-04-02 16:58:41 -0700736
Paul Clements7fdfd402007-10-16 23:27:37 -0700737 case NBD_SET_TIMEOUT:
Josef Bacik0eadf372016-09-08 12:33:40 -0700738 nbd->tag_set.timeout = arg * HZ;
Paul Clements7fdfd402007-10-16 23:27:37 -0700739 return 0;
Pavel Machek1a2ad212009-04-02 16:58:41 -0700740
Paul Clements2f012502012-10-04 17:16:15 -0700741 case NBD_SET_FLAGS:
742 nbd->flags = arg;
743 return 0;
744
Pavel Machek1a2ad212009-04-02 16:58:41 -0700745 case NBD_DO_IT: {
Josef Bacik9561a7a2016-11-22 14:04:40 -0500746 struct recv_thread_args *args;
747 int num_connections = nbd->num_connections;
Jens Axboefeffa5c2016-11-22 19:09:45 -0700748 int error = 0, i;
Pavel Machek1a2ad212009-04-02 16:58:41 -0700749
Markus Pargmann6521d392015-08-17 08:20:05 +0200750 if (nbd->task_recv)
Pavel Machekc91192d2009-01-15 13:51:03 -0800751 return -EBUSY;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500752 if (!nbd->socks)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 return -EINVAL;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500754 if (num_connections > 1 &&
755 !(nbd->flags & NBD_FLAG_CAN_MULTI_CONN)) {
756 dev_err(disk_to_dev(nbd->disk), "server does not support multiple connections per device.\n");
Jens Axboefeffa5c2016-11-22 19:09:45 -0700757 error = -EINVAL;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500758 goto out_err;
759 }
Pavel Machek1a2ad212009-04-02 16:58:41 -0700760
Josef Bacik9561a7a2016-11-22 14:04:40 -0500761 set_bit(NBD_RUNNING, &nbd->runtime_flags);
762 blk_mq_update_nr_hw_queues(&nbd->tag_set, nbd->num_connections);
763 args = kcalloc(num_connections, sizeof(*args), GFP_KERNEL);
Jens Axboefeffa5c2016-11-22 19:09:45 -0700764 if (!args) {
765 error = -ENOMEM;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500766 goto out_err;
Jens Axboefeffa5c2016-11-22 19:09:45 -0700767 }
Vegard Nossum97240962016-05-27 12:59:35 +0200768 nbd->task_recv = current;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500769 mutex_unlock(&nbd->config_lock);
Pavel Machek1a2ad212009-04-02 16:58:41 -0700770
Markus Pargmannd02cf532015-10-29 12:06:15 +0100771 nbd_parse_flags(nbd, bdev);
Paul Clementsa336d292012-10-04 17:16:18 -0700772
Josef Bacik9561a7a2016-11-22 14:04:40 -0500773 error = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
774 if (error) {
775 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
776 goto out_recv;
777 }
778
779 nbd_size_update(nbd, bdev);
780
Markus Pargmann30d53d92015-08-17 08:20:06 +0200781 nbd_dev_dbg_init(nbd);
Josef Bacik9561a7a2016-11-22 14:04:40 -0500782 for (i = 0; i < num_connections; i++) {
783 sk_set_memalloc(nbd->socks[i]->sock->sk);
784 atomic_inc(&nbd->recv_threads);
785 INIT_WORK(&args[i].work, recv_work);
786 args[i].nbd = nbd;
787 args[i].index = i;
788 queue_work(system_long_wq, &args[i].work);
789 }
790 wait_event_interruptible(nbd->recv_wq,
791 atomic_read(&nbd->recv_threads) == 0);
792 for (i = 0; i < num_connections; i++)
793 flush_work(&args[i].work);
Markus Pargmann30d53d92015-08-17 08:20:06 +0200794 nbd_dev_dbg_close(nbd);
Josef Bacik9561a7a2016-11-22 14:04:40 -0500795 nbd_size_clear(nbd, bdev);
796 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
797out_recv:
798 mutex_lock(&nbd->config_lock);
Vegard Nossum97240962016-05-27 12:59:35 +0200799 nbd->task_recv = NULL;
Josef Bacik9561a7a2016-11-22 14:04:40 -0500800out_err:
Markus Pargmann36e47be2015-08-17 08:20:01 +0200801 sock_shutdown(nbd);
Wanlong Gaof4507162012-03-28 14:42:51 -0700802 nbd_clear_que(nbd);
Paolo Bonzini3a2d63f82013-02-27 17:05:25 -0800803 kill_bdev(bdev);
Markus Pargmann0e4f0f62015-10-29 12:04:51 +0100804 nbd_bdev_reset(bdev);
805
Josef Bacik9b4a6ba2016-09-08 12:33:39 -0700806 /* user requested, ignore socket errors */
807 if (test_bit(NBD_DISCONNECT_REQUESTED, &nbd->runtime_flags))
Markus Pargmann1f7b5cf2015-10-29 12:01:34 +0100808 error = 0;
Josef Bacik9b4a6ba2016-09-08 12:33:39 -0700809 if (test_bit(NBD_TIMEDOUT, &nbd->runtime_flags))
Markus Pargmann1f7b5cf2015-10-29 12:01:34 +0100810 error = -ETIMEDOUT;
811
Markus Pargmann0e4f0f62015-10-29 12:04:51 +0100812 nbd_reset(nbd);
Markus Pargmann19391832015-08-17 08:20:03 +0200813 return error;
Pavel Machek1a2ad212009-04-02 16:58:41 -0700814 }
815
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816 case NBD_CLEAR_QUE:
Herbert Xu4b2f0262006-01-06 00:09:47 -0800817 /*
818 * This is for compatibility only. The queue is always cleared
819 * by NBD_DO_IT or NBD_CLEAR_SOCK.
820 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 return 0;
Pavel Machek1a2ad212009-04-02 16:58:41 -0700822
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823 case NBD_PRINT_DEBUG:
Josef Bacikfd8383f2016-09-08 12:33:37 -0700824 /*
825 * For compatibility only, we no longer keep a list of
826 * outstanding requests.
827 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 return 0;
829 }
Pavel Machek1a2ad212009-04-02 16:58:41 -0700830 return -ENOTTY;
831}
832
833static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
834 unsigned int cmd, unsigned long arg)
835{
Wanlong Gaof4507162012-03-28 14:42:51 -0700836 struct nbd_device *nbd = bdev->bd_disk->private_data;
Pavel Machek1a2ad212009-04-02 16:58:41 -0700837 int error;
838
839 if (!capable(CAP_SYS_ADMIN))
840 return -EPERM;
841
Wanlong Gaof4507162012-03-28 14:42:51 -0700842 BUG_ON(nbd->magic != NBD_MAGIC);
Pavel Machek1a2ad212009-04-02 16:58:41 -0700843
Josef Bacik9561a7a2016-11-22 14:04:40 -0500844 mutex_lock(&nbd->config_lock);
Wanlong Gaof4507162012-03-28 14:42:51 -0700845 error = __nbd_ioctl(bdev, nbd, cmd, arg);
Josef Bacik9561a7a2016-11-22 14:04:40 -0500846 mutex_unlock(&nbd->config_lock);
Pavel Machek1a2ad212009-04-02 16:58:41 -0700847
848 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849}
850
Alexey Dobriyan83d5cde2009-09-21 17:01:13 -0700851static const struct block_device_operations nbd_fops =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852{
853 .owner = THIS_MODULE,
Arnd Bergmann8a6cfeb2010-07-08 10:18:46 +0200854 .ioctl = nbd_ioctl,
Al Viro263a3df2016-01-07 10:04:37 -0500855 .compat_ioctl = nbd_ioctl,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856};
857
Markus Pargmann30d53d92015-08-17 08:20:06 +0200858#if IS_ENABLED(CONFIG_DEBUG_FS)
859
860static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
861{
862 struct nbd_device *nbd = s->private;
863
864 if (nbd->task_recv)
865 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
Markus Pargmann30d53d92015-08-17 08:20:06 +0200866
867 return 0;
868}
869
870static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
871{
872 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
873}
874
875static const struct file_operations nbd_dbg_tasks_ops = {
876 .open = nbd_dbg_tasks_open,
877 .read = seq_read,
878 .llseek = seq_lseek,
879 .release = single_release,
880};
881
882static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
883{
884 struct nbd_device *nbd = s->private;
885 u32 flags = nbd->flags;
886
887 seq_printf(s, "Hex: 0x%08x\n\n", flags);
888
889 seq_puts(s, "Known flags:\n");
890
891 if (flags & NBD_FLAG_HAS_FLAGS)
892 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
893 if (flags & NBD_FLAG_READ_ONLY)
894 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
895 if (flags & NBD_FLAG_SEND_FLUSH)
896 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
897 if (flags & NBD_FLAG_SEND_TRIM)
898 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
899
900 return 0;
901}
902
903static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
904{
905 return single_open(file, nbd_dbg_flags_show, inode->i_private);
906}
907
908static const struct file_operations nbd_dbg_flags_ops = {
909 .open = nbd_dbg_flags_open,
910 .read = seq_read,
911 .llseek = seq_lseek,
912 .release = single_release,
913};
914
915static int nbd_dev_dbg_init(struct nbd_device *nbd)
916{
917 struct dentry *dir;
Markus Pargmann27ea43f2015-10-24 21:15:34 +0200918
919 if (!nbd_dbg_dir)
920 return -EIO;
Markus Pargmann30d53d92015-08-17 08:20:06 +0200921
922 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
Markus Pargmann27ea43f2015-10-24 21:15:34 +0200923 if (!dir) {
924 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
925 nbd_name(nbd));
926 return -EIO;
Markus Pargmann30d53d92015-08-17 08:20:06 +0200927 }
928 nbd->dbg_dir = dir;
929
Markus Pargmann27ea43f2015-10-24 21:15:34 +0200930 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
931 debugfs_create_u64("size_bytes", 0444, dir, &nbd->bytesize);
Josef Bacik0eadf372016-09-08 12:33:40 -0700932 debugfs_create_u32("timeout", 0444, dir, &nbd->tag_set.timeout);
Josef Bacikef77b512016-12-02 16:19:12 -0500933 debugfs_create_u64("blocksize", 0444, dir, &nbd->blksize);
Josef Bacikd366a0f2016-06-08 10:32:10 -0400934 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
Markus Pargmann30d53d92015-08-17 08:20:06 +0200935
936 return 0;
937}
938
939static void nbd_dev_dbg_close(struct nbd_device *nbd)
940{
941 debugfs_remove_recursive(nbd->dbg_dir);
942}
943
944static int nbd_dbg_init(void)
945{
946 struct dentry *dbg_dir;
947
948 dbg_dir = debugfs_create_dir("nbd", NULL);
Markus Pargmann27ea43f2015-10-24 21:15:34 +0200949 if (!dbg_dir)
950 return -EIO;
Markus Pargmann30d53d92015-08-17 08:20:06 +0200951
952 nbd_dbg_dir = dbg_dir;
953
954 return 0;
955}
956
957static void nbd_dbg_close(void)
958{
959 debugfs_remove_recursive(nbd_dbg_dir);
960}
961
962#else /* IS_ENABLED(CONFIG_DEBUG_FS) */
963
964static int nbd_dev_dbg_init(struct nbd_device *nbd)
965{
966 return 0;
967}
968
969static void nbd_dev_dbg_close(struct nbd_device *nbd)
970{
971}
972
973static int nbd_dbg_init(void)
974{
975 return 0;
976}
977
978static void nbd_dbg_close(void)
979{
980}
981
982#endif
983
Josef Bacikfd8383f2016-09-08 12:33:37 -0700984static int nbd_init_request(void *data, struct request *rq,
985 unsigned int hctx_idx, unsigned int request_idx,
986 unsigned int numa_node)
987{
988 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
Josef Bacikfd8383f2016-09-08 12:33:37 -0700989 cmd->nbd = data;
Josef Bacikfd8383f2016-09-08 12:33:37 -0700990 return 0;
991}
992
993static struct blk_mq_ops nbd_mq_ops = {
994 .queue_rq = nbd_queue_rq,
Josef Bacikfd8383f2016-09-08 12:33:37 -0700995 .init_request = nbd_init_request,
Josef Bacik0eadf372016-09-08 12:33:40 -0700996 .timeout = nbd_xmit_timeout,
Josef Bacikfd8383f2016-09-08 12:33:37 -0700997};
998
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999/*
1000 * And here should be modules and kernel interface
1001 * (Just smiley confuses emacs :-)
1002 */
1003
1004static int __init nbd_init(void)
1005{
1006 int err = -ENOMEM;
1007 int i;
Laurent Vivierd71a6d72008-04-29 01:02:51 -07001008 int part_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009
Adrian Bunk5b7b18c2006-03-25 03:07:04 -08001010 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011
Laurent Vivierd71a6d72008-04-29 01:02:51 -07001012 if (max_part < 0) {
WANG Cong7742ce42011-08-19 14:48:28 +02001013 printk(KERN_ERR "nbd: max_part must be >= 0\n");
Laurent Vivierd71a6d72008-04-29 01:02:51 -07001014 return -EINVAL;
1015 }
1016
1017 part_shift = 0;
Namhyung Kim5988ce22011-05-28 14:44:46 +02001018 if (max_part > 0) {
Laurent Vivierd71a6d72008-04-29 01:02:51 -07001019 part_shift = fls(max_part);
1020
Namhyung Kim5988ce22011-05-28 14:44:46 +02001021 /*
1022 * Adjust max_part according to part_shift as it is exported
1023 * to user space so that user can know the max number of
1024 * partition kernel should be able to manage.
1025 *
1026 * Note that -1 is required because partition 0 is reserved
1027 * for the whole disk.
1028 */
1029 max_part = (1UL << part_shift) - 1;
1030 }
1031
Namhyung Kim3b271082011-05-28 14:44:46 +02001032 if ((1UL << part_shift) > DISK_MAX_PARTS)
1033 return -EINVAL;
1034
1035 if (nbds_max > 1UL << (MINORBITS - part_shift))
1036 return -EINVAL;
1037
Sudip Mukherjeeff6b8092015-01-27 18:08:22 +05301038 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
1039 if (!nbd_dev)
1040 return -ENOMEM;
1041
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -07001042 for (i = 0; i < nbds_max; i++) {
Jeff Moyer25b4acf2017-01-09 15:20:31 -05001043 struct request_queue *q;
Laurent Vivierd71a6d72008-04-29 01:02:51 -07001044 struct gendisk *disk = alloc_disk(1 << part_shift);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045 if (!disk)
1046 goto out;
1047 nbd_dev[i].disk = disk;
Josef Bacikfd8383f2016-09-08 12:33:37 -07001048
1049 nbd_dev[i].tag_set.ops = &nbd_mq_ops;
1050 nbd_dev[i].tag_set.nr_hw_queues = 1;
1051 nbd_dev[i].tag_set.queue_depth = 128;
1052 nbd_dev[i].tag_set.numa_node = NUMA_NO_NODE;
1053 nbd_dev[i].tag_set.cmd_size = sizeof(struct nbd_cmd);
1054 nbd_dev[i].tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
Josef Bacik005043a2016-09-21 16:55:31 -04001055 BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING;
Josef Bacikfd8383f2016-09-08 12:33:37 -07001056 nbd_dev[i].tag_set.driver_data = &nbd_dev[i];
1057
1058 err = blk_mq_alloc_tag_set(&nbd_dev[i].tag_set);
1059 if (err) {
1060 put_disk(disk);
1061 goto out;
1062 }
1063
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064 /*
1065 * The new linux 2.5 block layer implementation requires
1066 * every gendisk to have its very own request_queue struct.
1067 * These structs are big so we dynamically allocate them.
1068 */
Jeff Moyer25b4acf2017-01-09 15:20:31 -05001069 q = blk_mq_init_queue(&nbd_dev[i].tag_set);
1070 if (IS_ERR(q)) {
Josef Bacikfd8383f2016-09-08 12:33:37 -07001071 blk_mq_free_tag_set(&nbd_dev[i].tag_set);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072 put_disk(disk);
1073 goto out;
1074 }
Jeff Moyer25b4acf2017-01-09 15:20:31 -05001075 disk->queue = q;
Josef Bacikfd8383f2016-09-08 12:33:37 -07001076
Jens Axboe31dcfab2008-10-31 10:06:37 +01001077 /*
1078 * Tell the block layer that we are not a rotational device
1079 */
1080 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
Mike Snitzerb277da02014-10-04 10:55:32 -06001081 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue);
Paul Clementsa336d292012-10-04 17:16:18 -07001082 disk->queue->limits.discard_granularity = 512;
Jens Axboe2bb4cd52015-07-14 08:15:12 -06001083 blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
Paul Clementsa336d292012-10-04 17:16:18 -07001084 disk->queue->limits.discard_zeroes_data = 0;
Michal Belczyk078be022013-04-30 15:28:28 -07001085 blk_queue_max_hw_sectors(disk->queue, 65536);
1086 disk->queue->limits.max_sectors = 256;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 }
1088
1089 if (register_blkdev(NBD_MAJOR, "nbd")) {
1090 err = -EIO;
1091 goto out;
1092 }
1093
1094 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095
Markus Pargmann30d53d92015-08-17 08:20:06 +02001096 nbd_dbg_init();
1097
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -07001098 for (i = 0; i < nbds_max; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099 struct gendisk *disk = nbd_dev[i].disk;
Wanlong Gaof4507162012-03-28 14:42:51 -07001100 nbd_dev[i].magic = NBD_MAGIC;
Josef Bacik9561a7a2016-11-22 14:04:40 -05001101 mutex_init(&nbd_dev[i].config_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 disk->major = NBD_MAJOR;
Laurent Vivierd71a6d72008-04-29 01:02:51 -07001103 disk->first_minor = i << part_shift;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001104 disk->fops = &nbd_fops;
1105 disk->private_data = &nbd_dev[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106 sprintf(disk->disk_name, "nbd%d", i);
Josef Bacik9561a7a2016-11-22 14:04:40 -05001107 init_waitqueue_head(&nbd_dev[i].recv_wq);
Markus Pargmann0e4f0f62015-10-29 12:04:51 +01001108 nbd_reset(&nbd_dev[i]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001109 add_disk(disk);
1110 }
1111
1112 return 0;
1113out:
1114 while (i--) {
Josef Bacikfd8383f2016-09-08 12:33:37 -07001115 blk_mq_free_tag_set(&nbd_dev[i].tag_set);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 blk_cleanup_queue(nbd_dev[i].disk->queue);
1117 put_disk(nbd_dev[i].disk);
1118 }
Sven Wegenerf3944d62008-08-20 14:09:07 -07001119 kfree(nbd_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120 return err;
1121}
1122
1123static void __exit nbd_cleanup(void)
1124{
1125 int i;
Markus Pargmann30d53d92015-08-17 08:20:06 +02001126
1127 nbd_dbg_close();
1128
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -07001129 for (i = 0; i < nbds_max; i++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130 struct gendisk *disk = nbd_dev[i].disk;
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -07001131 nbd_dev[i].magic = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132 if (disk) {
1133 del_gendisk(disk);
1134 blk_cleanup_queue(disk->queue);
Josef Bacikfd8383f2016-09-08 12:33:37 -07001135 blk_mq_free_tag_set(&nbd_dev[i].tag_set);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001136 put_disk(disk);
1137 }
1138 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139 unregister_blkdev(NBD_MAJOR, "nbd");
Sven Wegenerf3944d62008-08-20 14:09:07 -07001140 kfree(nbd_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
1142}
1143
1144module_init(nbd_init);
1145module_exit(nbd_cleanup);
1146
1147MODULE_DESCRIPTION("Network Block Device");
1148MODULE_LICENSE("GPL");
1149
Lars Marowsky-Bree40be0c22005-05-01 08:59:07 -07001150module_param(nbds_max, int, 0444);
Laurent Vivierd71a6d72008-04-29 01:02:51 -07001151MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
1152module_param(max_part, int, 0444);
1153MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");