2 * Network block device - make block devices work over TCP
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.
7 * Copyright 1997-2000, 2008 Pavel Machek <pavel@ucw.cz>
8 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
10 * This file is released under GPLv2 or later.
12 * (part of code stolen from loop.c)
15 #include <linux/major.h>
17 #include <linux/blkdev.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/sched.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>
27 #include <linux/mutex.h>
28 #include <linux/compiler.h>
29 #include <linux/err.h>
30 #include <linux/kernel.h>
31 #include <linux/slab.h>
33 #include <linux/net.h>
34 #include <linux/kthread.h>
35 #include <linux/types.h>
36 #include <linux/debugfs.h>
37 #include <linux/blk-mq.h>
39 #include <asm/uaccess.h>
40 #include <asm/types.h>
42 #include <linux/nbd.h>
46 struct socket * sock; /* If == NULL, device is not ready, yet */
49 atomic_t outstanding_cmds;
50 struct blk_mq_tag_set tag_set;
58 bool disconnect; /* a disconnect has been requested by user */
60 struct timer_list timeout_timer;
61 /* protects initialization and shutdown of the socket */
63 struct task_struct *task_recv;
64 struct task_struct *task_send;
66 #if IS_ENABLED(CONFIG_DEBUG_FS)
67 struct dentry *dbg_dir;
72 struct nbd_device *nbd;
73 struct list_head list;
76 #if IS_ENABLED(CONFIG_DEBUG_FS)
77 static struct dentry *nbd_dbg_dir;
80 #define nbd_name(nbd) ((nbd)->disk->disk_name)
82 #define NBD_MAGIC 0x68797548
84 static unsigned int nbds_max = 16;
85 static struct nbd_device *nbd_dev;
88 static inline struct device *nbd_to_dev(struct nbd_device *nbd)
90 return disk_to_dev(nbd->disk);
93 static bool nbd_is_connected(struct nbd_device *nbd)
95 return !!nbd->task_recv;
98 static const char *nbdcmd_to_ascii(int cmd)
101 case NBD_CMD_READ: return "read";
102 case NBD_CMD_WRITE: return "write";
103 case NBD_CMD_DISC: return "disconnect";
104 case NBD_CMD_FLUSH: return "flush";
105 case NBD_CMD_TRIM: return "trim/discard";
110 static int nbd_size_clear(struct nbd_device *nbd, struct block_device *bdev)
112 bdev->bd_inode->i_size = 0;
113 set_capacity(nbd->disk, 0);
114 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
119 static void nbd_size_update(struct nbd_device *nbd, struct block_device *bdev)
121 if (!nbd_is_connected(nbd))
124 bdev->bd_inode->i_size = nbd->bytesize;
125 set_capacity(nbd->disk, nbd->bytesize >> 9);
126 kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
129 static int nbd_size_set(struct nbd_device *nbd, struct block_device *bdev,
130 int blocksize, int nr_blocks)
134 ret = set_blocksize(bdev, blocksize);
138 nbd->blksize = blocksize;
139 nbd->bytesize = (loff_t)blocksize * (loff_t)nr_blocks;
141 nbd_size_update(nbd, bdev);
146 static void nbd_end_request(struct nbd_cmd *cmd)
148 struct nbd_device *nbd = cmd->nbd;
149 struct request *req = blk_mq_rq_from_pdu(cmd);
150 int error = req->errors ? -EIO : 0;
152 dev_dbg(nbd_to_dev(nbd), "request %p: %s\n", cmd,
153 error ? "failed" : "done");
155 atomic_dec(&nbd->outstanding_cmds);
156 blk_mq_complete_request(req, error);
160 * Forcibly shutdown the socket causing all listeners to error
162 static void sock_shutdown(struct nbd_device *nbd)
166 spin_lock_irq(&nbd->sock_lock);
169 spin_unlock_irq(&nbd->sock_lock);
174 dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n");
176 spin_unlock_irq(&nbd->sock_lock);
178 kernel_sock_shutdown(sock, SHUT_RDWR);
181 del_timer(&nbd->timeout_timer);
184 static void nbd_xmit_timeout(unsigned long arg)
186 struct nbd_device *nbd = (struct nbd_device *)arg;
187 struct socket *sock = NULL;
190 if (!atomic_read(&nbd->outstanding_cmds))
193 spin_lock_irqsave(&nbd->sock_lock, flags);
195 nbd->timedout = true;
199 get_file(sock->file);
202 spin_unlock_irqrestore(&nbd->sock_lock, flags);
204 kernel_sock_shutdown(sock, SHUT_RDWR);
208 dev_err(nbd_to_dev(nbd), "Connection timed out, shutting down connection\n");
212 * Send or receive packet.
214 static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
217 struct socket *sock = nbd->sock;
221 unsigned long pflags = current->flags;
223 if (unlikely(!sock)) {
224 dev_err(disk_to_dev(nbd->disk),
225 "Attempted %s on closed socket in sock_xmit\n",
226 (send ? "send" : "recv"));
230 current->flags |= PF_MEMALLOC;
232 sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
237 msg.msg_control = NULL;
238 msg.msg_controllen = 0;
239 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
242 result = kernel_sendmsg(sock, &msg, &iov, 1, size);
244 result = kernel_recvmsg(sock, &msg, &iov, 1, size,
249 result = -EPIPE; /* short read */
256 tsk_restore_flags(current, pflags, PF_MEMALLOC);
258 if (!send && nbd->xmit_timeout)
259 mod_timer(&nbd->timeout_timer, jiffies + nbd->xmit_timeout);
264 static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec,
268 void *kaddr = kmap(bvec->bv_page);
269 result = sock_xmit(nbd, 1, kaddr + bvec->bv_offset,
270 bvec->bv_len, flags);
271 kunmap(bvec->bv_page);
275 /* always call with the tx_lock held */
276 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd)
278 struct request *req = blk_mq_rq_from_pdu(cmd);
280 struct nbd_request request;
281 unsigned long size = blk_rq_bytes(req);
284 if (req->cmd_type == REQ_TYPE_DRV_PRIV)
286 else if (req_op(req) == REQ_OP_DISCARD)
288 else if (req_op(req) == REQ_OP_FLUSH)
289 type = NBD_CMD_FLUSH;
290 else if (rq_data_dir(req) == WRITE)
291 type = NBD_CMD_WRITE;
295 memset(&request, 0, sizeof(request));
296 request.magic = htonl(NBD_REQUEST_MAGIC);
297 request.type = htonl(type);
298 if (type != NBD_CMD_FLUSH && type != NBD_CMD_DISC) {
299 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
300 request.len = htonl(size);
302 memcpy(request.handle, &req->tag, sizeof(req->tag));
304 dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n",
305 cmd, nbdcmd_to_ascii(type),
306 (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req));
307 result = sock_xmit(nbd, 1, &request, sizeof(request),
308 (type == NBD_CMD_WRITE) ? MSG_MORE : 0);
310 dev_err(disk_to_dev(nbd->disk),
311 "Send control failed (result %d)\n", result);
315 if (type == NBD_CMD_WRITE) {
316 struct req_iterator iter;
319 * we are really probing at internals to determine
320 * whether to set MSG_MORE or not...
322 rq_for_each_segment(bvec, req, iter) {
324 if (!rq_iter_last(bvec, iter))
326 dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
328 result = sock_send_bvec(nbd, &bvec, flags);
330 dev_err(disk_to_dev(nbd->disk),
331 "Send data failed (result %d)\n",
340 static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec)
343 void *kaddr = kmap(bvec->bv_page);
344 result = sock_xmit(nbd, 0, kaddr + bvec->bv_offset, bvec->bv_len,
346 kunmap(bvec->bv_page);
350 /* NULL returned = something went wrong, inform userspace */
351 static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd)
354 struct nbd_reply reply;
356 struct request *req = NULL;
361 result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL);
363 dev_err(disk_to_dev(nbd->disk),
364 "Receive control failed (result %d)\n", result);
365 return ERR_PTR(result);
368 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
369 dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n",
370 (unsigned long)ntohl(reply.magic));
371 return ERR_PTR(-EPROTO);
374 memcpy(&tag, reply.handle, sizeof(int));
376 hwq = blk_mq_unique_tag_to_hwq(tag);
377 if (hwq < nbd->tag_set.nr_hw_queues)
378 req = blk_mq_tag_to_rq(nbd->tag_set.tags[hwq],
379 blk_mq_unique_tag_to_tag(tag));
380 if (!req || !blk_mq_request_started(req)) {
381 dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%d) %p\n",
383 return ERR_PTR(-ENOENT);
385 cmd = blk_mq_rq_to_pdu(req);
387 if (ntohl(reply.error)) {
388 dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n",
394 dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", cmd);
395 if (rq_data_dir(req) != WRITE) {
396 struct req_iterator iter;
399 rq_for_each_segment(bvec, req, iter) {
400 result = sock_recv_bvec(nbd, &bvec);
402 dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
407 dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n",
414 static ssize_t pid_show(struct device *dev,
415 struct device_attribute *attr, char *buf)
417 struct gendisk *disk = dev_to_disk(dev);
418 struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
420 return sprintf(buf, "%d\n", task_pid_nr(nbd->task_recv));
423 static struct device_attribute pid_attr = {
424 .attr = { .name = "pid", .mode = S_IRUGO},
428 static int nbd_thread_recv(struct nbd_device *nbd, struct block_device *bdev)
433 BUG_ON(nbd->magic != NBD_MAGIC);
435 sk_set_memalloc(nbd->sock->sk);
437 ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
439 dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n");
443 nbd_size_update(nbd, bdev);
446 cmd = nbd_read_stat(nbd);
452 nbd_end_request(cmd);
455 nbd_size_clear(nbd, bdev);
457 device_remove_file(disk_to_dev(nbd->disk), &pid_attr);
461 static void nbd_clear_req(struct request *req, void *data, bool reserved)
465 if (!blk_mq_request_started(req))
467 cmd = blk_mq_rq_to_pdu(req);
469 nbd_end_request(cmd);
472 static void nbd_clear_que(struct nbd_device *nbd)
474 BUG_ON(nbd->magic != NBD_MAGIC);
477 * Because we have set nbd->sock to NULL under the tx_lock, all
478 * modifications to the list must have completed by now.
482 blk_mq_tagset_busy_iter(&nbd->tag_set, nbd_clear_req, NULL);
483 dev_dbg(disk_to_dev(nbd->disk), "queue cleared\n");
487 static void nbd_handle_cmd(struct nbd_cmd *cmd)
489 struct request *req = blk_mq_rq_from_pdu(cmd);
490 struct nbd_device *nbd = cmd->nbd;
492 if (req->cmd_type != REQ_TYPE_FS)
495 if (rq_data_dir(req) == WRITE &&
496 (nbd->flags & NBD_FLAG_READ_ONLY)) {
497 dev_err(disk_to_dev(nbd->disk),
498 "Write on read-only\n");
504 mutex_lock(&nbd->tx_lock);
505 nbd->task_send = current;
506 if (unlikely(!nbd->sock)) {
507 mutex_unlock(&nbd->tx_lock);
508 dev_err(disk_to_dev(nbd->disk),
509 "Attempted send on closed socket\n");
513 if (nbd->xmit_timeout && !atomic_read(&nbd->outstanding_cmds))
514 mod_timer(&nbd->timeout_timer, jiffies + nbd->xmit_timeout);
516 atomic_inc(&nbd->outstanding_cmds);
517 if (nbd_send_cmd(nbd, cmd) != 0) {
518 dev_err(disk_to_dev(nbd->disk), "Request send failed\n");
520 nbd_end_request(cmd);
523 nbd->task_send = NULL;
524 mutex_unlock(&nbd->tx_lock);
530 nbd_end_request(cmd);
533 static int nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
534 const struct blk_mq_queue_data *bd)
536 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
538 blk_mq_start_request(bd->rq);
540 return BLK_MQ_RQ_QUEUE_OK;
543 static int nbd_set_socket(struct nbd_device *nbd, struct socket *sock)
547 spin_lock_irq(&nbd->sock_lock);
557 spin_unlock_irq(&nbd->sock_lock);
562 /* Reset all properties of an NBD device */
563 static void nbd_reset(struct nbd_device *nbd)
565 nbd->disconnect = false;
566 nbd->timedout = false;
569 set_capacity(nbd->disk, 0);
571 nbd->xmit_timeout = 0;
572 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
573 del_timer_sync(&nbd->timeout_timer);
576 static void nbd_bdev_reset(struct block_device *bdev)
578 set_device_ro(bdev, false);
579 bdev->bd_inode->i_size = 0;
581 blkdev_reread_part(bdev);
582 bdev->bd_invalidated = 1;
586 static void nbd_parse_flags(struct nbd_device *nbd, struct block_device *bdev)
588 if (nbd->flags & NBD_FLAG_READ_ONLY)
589 set_device_ro(bdev, true);
590 if (nbd->flags & NBD_FLAG_SEND_TRIM)
591 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue);
592 if (nbd->flags & NBD_FLAG_SEND_FLUSH)
593 blk_queue_write_cache(nbd->disk->queue, true, false);
595 blk_queue_write_cache(nbd->disk->queue, false, false);
598 static int nbd_dev_dbg_init(struct nbd_device *nbd);
599 static void nbd_dev_dbg_close(struct nbd_device *nbd);
601 /* Must be called with tx_lock held */
603 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
604 unsigned int cmd, unsigned long arg)
607 case NBD_DISCONNECT: {
608 struct request *sreq;
610 dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n");
614 sreq = blk_mq_alloc_request(bdev_get_queue(bdev), WRITE, 0);
618 mutex_unlock(&nbd->tx_lock);
620 mutex_lock(&nbd->tx_lock);
621 sreq->cmd_type = REQ_TYPE_DRV_PRIV;
623 /* Check again after getting mutex back. */
625 blk_mq_free_request(sreq);
629 nbd->disconnect = true;
631 nbd_send_cmd(nbd, blk_mq_rq_to_pdu(sreq));
632 blk_mq_free_request(sreq);
644 struct socket *sock = sockfd_lookup(arg, &err);
649 err = nbd_set_socket(nbd, sock);
650 if (!err && max_part)
651 bdev->bd_invalidated = 1;
656 case NBD_SET_BLKSIZE: {
657 loff_t bsize = div_s64(nbd->bytesize, arg);
659 return nbd_size_set(nbd, bdev, arg, bsize);
663 return nbd_size_set(nbd, bdev, nbd->blksize,
666 case NBD_SET_SIZE_BLOCKS:
667 return nbd_size_set(nbd, bdev, nbd->blksize, arg);
669 case NBD_SET_TIMEOUT:
670 nbd->xmit_timeout = arg * HZ;
672 mod_timer(&nbd->timeout_timer,
673 jiffies + nbd->xmit_timeout);
675 del_timer_sync(&nbd->timeout_timer);
691 /* We have to claim the device under the lock */
692 nbd->task_recv = current;
693 mutex_unlock(&nbd->tx_lock);
695 nbd_parse_flags(nbd, bdev);
697 nbd_dev_dbg_init(nbd);
698 error = nbd_thread_recv(nbd, bdev);
699 nbd_dev_dbg_close(nbd);
701 mutex_lock(&nbd->tx_lock);
702 nbd->task_recv = NULL;
707 nbd_bdev_reset(bdev);
709 if (nbd->disconnect) /* user requested, ignore socket errors */
721 * This is for compatibility only. The queue is always cleared
722 * by NBD_DO_IT or NBD_CLEAR_SOCK.
726 case NBD_PRINT_DEBUG:
728 * For compatibility only, we no longer keep a list of
729 * outstanding requests.
736 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
737 unsigned int cmd, unsigned long arg)
739 struct nbd_device *nbd = bdev->bd_disk->private_data;
742 if (!capable(CAP_SYS_ADMIN))
745 BUG_ON(nbd->magic != NBD_MAGIC);
747 mutex_lock(&nbd->tx_lock);
748 error = __nbd_ioctl(bdev, nbd, cmd, arg);
749 mutex_unlock(&nbd->tx_lock);
754 static const struct block_device_operations nbd_fops =
756 .owner = THIS_MODULE,
758 .compat_ioctl = nbd_ioctl,
761 #if IS_ENABLED(CONFIG_DEBUG_FS)
763 static int nbd_dbg_tasks_show(struct seq_file *s, void *unused)
765 struct nbd_device *nbd = s->private;
768 seq_printf(s, "recv: %d\n", task_pid_nr(nbd->task_recv));
770 seq_printf(s, "send: %d\n", task_pid_nr(nbd->task_send));
775 static int nbd_dbg_tasks_open(struct inode *inode, struct file *file)
777 return single_open(file, nbd_dbg_tasks_show, inode->i_private);
780 static const struct file_operations nbd_dbg_tasks_ops = {
781 .open = nbd_dbg_tasks_open,
784 .release = single_release,
787 static int nbd_dbg_flags_show(struct seq_file *s, void *unused)
789 struct nbd_device *nbd = s->private;
790 u32 flags = nbd->flags;
792 seq_printf(s, "Hex: 0x%08x\n\n", flags);
794 seq_puts(s, "Known flags:\n");
796 if (flags & NBD_FLAG_HAS_FLAGS)
797 seq_puts(s, "NBD_FLAG_HAS_FLAGS\n");
798 if (flags & NBD_FLAG_READ_ONLY)
799 seq_puts(s, "NBD_FLAG_READ_ONLY\n");
800 if (flags & NBD_FLAG_SEND_FLUSH)
801 seq_puts(s, "NBD_FLAG_SEND_FLUSH\n");
802 if (flags & NBD_FLAG_SEND_TRIM)
803 seq_puts(s, "NBD_FLAG_SEND_TRIM\n");
808 static int nbd_dbg_flags_open(struct inode *inode, struct file *file)
810 return single_open(file, nbd_dbg_flags_show, inode->i_private);
813 static const struct file_operations nbd_dbg_flags_ops = {
814 .open = nbd_dbg_flags_open,
817 .release = single_release,
820 static int nbd_dev_dbg_init(struct nbd_device *nbd)
827 dir = debugfs_create_dir(nbd_name(nbd), nbd_dbg_dir);
829 dev_err(nbd_to_dev(nbd), "Failed to create debugfs dir for '%s'\n",
835 debugfs_create_file("tasks", 0444, dir, nbd, &nbd_dbg_tasks_ops);
836 debugfs_create_u64("size_bytes", 0444, dir, &nbd->bytesize);
837 debugfs_create_u32("timeout", 0444, dir, &nbd->xmit_timeout);
838 debugfs_create_u32("blocksize", 0444, dir, &nbd->blksize);
839 debugfs_create_file("flags", 0444, dir, nbd, &nbd_dbg_flags_ops);
844 static void nbd_dev_dbg_close(struct nbd_device *nbd)
846 debugfs_remove_recursive(nbd->dbg_dir);
849 static int nbd_dbg_init(void)
851 struct dentry *dbg_dir;
853 dbg_dir = debugfs_create_dir("nbd", NULL);
857 nbd_dbg_dir = dbg_dir;
862 static void nbd_dbg_close(void)
864 debugfs_remove_recursive(nbd_dbg_dir);
867 #else /* IS_ENABLED(CONFIG_DEBUG_FS) */
869 static int nbd_dev_dbg_init(struct nbd_device *nbd)
874 static void nbd_dev_dbg_close(struct nbd_device *nbd)
878 static int nbd_dbg_init(void)
883 static void nbd_dbg_close(void)
889 static int nbd_init_request(void *data, struct request *rq,
890 unsigned int hctx_idx, unsigned int request_idx,
891 unsigned int numa_node)
893 struct nbd_cmd *cmd = blk_mq_rq_to_pdu(rq);
896 INIT_LIST_HEAD(&cmd->list);
900 static struct blk_mq_ops nbd_mq_ops = {
901 .queue_rq = nbd_queue_rq,
902 .map_queue = blk_mq_map_queue,
903 .init_request = nbd_init_request,
907 * And here should be modules and kernel interface
908 * (Just smiley confuses emacs :-)
911 static int __init nbd_init(void)
917 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
920 printk(KERN_ERR "nbd: max_part must be >= 0\n");
926 part_shift = fls(max_part);
929 * Adjust max_part according to part_shift as it is exported
930 * to user space so that user can know the max number of
931 * partition kernel should be able to manage.
933 * Note that -1 is required because partition 0 is reserved
934 * for the whole disk.
936 max_part = (1UL << part_shift) - 1;
939 if ((1UL << part_shift) > DISK_MAX_PARTS)
942 if (nbds_max > 1UL << (MINORBITS - part_shift))
945 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
949 for (i = 0; i < nbds_max; i++) {
950 struct gendisk *disk = alloc_disk(1 << part_shift);
953 nbd_dev[i].disk = disk;
955 nbd_dev[i].tag_set.ops = &nbd_mq_ops;
956 nbd_dev[i].tag_set.nr_hw_queues = 1;
957 nbd_dev[i].tag_set.queue_depth = 128;
958 nbd_dev[i].tag_set.numa_node = NUMA_NO_NODE;
959 nbd_dev[i].tag_set.cmd_size = sizeof(struct nbd_cmd);
960 nbd_dev[i].tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
962 nbd_dev[i].tag_set.driver_data = &nbd_dev[i];
964 err = blk_mq_alloc_tag_set(&nbd_dev[i].tag_set);
971 * The new linux 2.5 block layer implementation requires
972 * every gendisk to have its very own request_queue struct.
973 * These structs are big so we dynamically allocate them.
975 disk->queue = blk_mq_init_queue(&nbd_dev[i].tag_set);
977 blk_mq_free_tag_set(&nbd_dev[i].tag_set);
983 * Tell the block layer that we are not a rotational device
985 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
986 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue);
987 disk->queue->limits.discard_granularity = 512;
988 blk_queue_max_discard_sectors(disk->queue, UINT_MAX);
989 disk->queue->limits.discard_zeroes_data = 0;
990 blk_queue_max_hw_sectors(disk->queue, 65536);
991 disk->queue->limits.max_sectors = 256;
994 if (register_blkdev(NBD_MAJOR, "nbd")) {
999 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
1003 for (i = 0; i < nbds_max; i++) {
1004 struct gendisk *disk = nbd_dev[i].disk;
1005 nbd_dev[i].magic = NBD_MAGIC;
1006 spin_lock_init(&nbd_dev[i].sock_lock);
1007 mutex_init(&nbd_dev[i].tx_lock);
1008 init_timer(&nbd_dev[i].timeout_timer);
1009 nbd_dev[i].timeout_timer.function = nbd_xmit_timeout;
1010 nbd_dev[i].timeout_timer.data = (unsigned long)&nbd_dev[i];
1011 atomic_set(&nbd_dev[i].outstanding_cmds, 0);
1012 disk->major = NBD_MAJOR;
1013 disk->first_minor = i << part_shift;
1014 disk->fops = &nbd_fops;
1015 disk->private_data = &nbd_dev[i];
1016 sprintf(disk->disk_name, "nbd%d", i);
1017 nbd_reset(&nbd_dev[i]);
1024 blk_mq_free_tag_set(&nbd_dev[i].tag_set);
1025 blk_cleanup_queue(nbd_dev[i].disk->queue);
1026 put_disk(nbd_dev[i].disk);
1032 static void __exit nbd_cleanup(void)
1038 for (i = 0; i < nbds_max; i++) {
1039 struct gendisk *disk = nbd_dev[i].disk;
1040 nbd_dev[i].magic = 0;
1043 blk_cleanup_queue(disk->queue);
1044 blk_mq_free_tag_set(&nbd_dev[i].tag_set);
1048 unregister_blkdev(NBD_MAJOR, "nbd");
1050 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
1053 module_init(nbd_init);
1054 module_exit(nbd_cleanup);
1056 MODULE_DESCRIPTION("Network Block Device");
1057 MODULE_LICENSE("GPL");
1059 module_param(nbds_max, int, 0444);
1060 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
1061 module_param(max_part, int, 0444);
1062 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");