Use dentry_path() to create full path to inode object
[pohmelfs.git] / drivers / block / nbd.c
blobc3f0ee16594dac8d33b92d2dafd02a6ee4e1526d
1 /*
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.
6 *
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>
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>
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>
32 #include <net/sock.h>
33 #include <linux/net.h>
34 #include <linux/kthread.h>
36 #include <asm/uaccess.h>
37 #include <asm/system.h>
38 #include <asm/types.h>
40 #include <linux/nbd.h>
42 #define LO_MAGIC 0x68797548
44 #ifdef NDEBUG
45 #define dprintk(flags, fmt...)
46 #else /* NDEBUG */
47 #define dprintk(flags, fmt...) do { \
48 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \
49 } while (0)
50 #define DBG_IOCTL 0x0004
51 #define DBG_INIT 0x0010
52 #define DBG_EXIT 0x0020
53 #define DBG_BLKDEV 0x0100
54 #define DBG_RX 0x0200
55 #define DBG_TX 0x0400
56 static unsigned int debugflags;
57 #endif /* NDEBUG */
59 static unsigned int nbds_max = 16;
60 static struct nbd_device *nbd_dev;
61 static int max_part;
64 * Use just one lock (or at most 1 per NIC). Two arguments for this:
65 * 1. Each NIC is essentially a synchronization point for all servers
66 * accessed through that NIC so there's no need to have more locks
67 * than NICs anyway.
68 * 2. More locks lead to more "Dirty cache line bouncing" which will slow
69 * down each lock to the point where they're actually slower than just
70 * a single lock.
71 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this!
73 static DEFINE_SPINLOCK(nbd_lock);
75 #ifndef NDEBUG
76 static const char *ioctl_cmd_to_ascii(int cmd)
78 switch (cmd) {
79 case NBD_SET_SOCK: return "set-sock";
80 case NBD_SET_BLKSIZE: return "set-blksize";
81 case NBD_SET_SIZE: return "set-size";
82 case NBD_DO_IT: return "do-it";
83 case NBD_CLEAR_SOCK: return "clear-sock";
84 case NBD_CLEAR_QUE: return "clear-que";
85 case NBD_PRINT_DEBUG: return "print-debug";
86 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks";
87 case NBD_DISCONNECT: return "disconnect";
88 case BLKROSET: return "set-read-only";
89 case BLKFLSBUF: return "flush-buffer-cache";
91 return "unknown";
94 static const char *nbdcmd_to_ascii(int cmd)
96 switch (cmd) {
97 case NBD_CMD_READ: return "read";
98 case NBD_CMD_WRITE: return "write";
99 case NBD_CMD_DISC: return "disconnect";
101 return "invalid";
103 #endif /* NDEBUG */
105 static void nbd_end_request(struct request *req)
107 int error = req->errors ? -EIO : 0;
108 struct request_queue *q = req->q;
109 unsigned long flags;
111 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
112 req, error ? "failed" : "done");
114 spin_lock_irqsave(q->queue_lock, flags);
115 __blk_end_request_all(req, error);
116 spin_unlock_irqrestore(q->queue_lock, flags);
119 static void sock_shutdown(struct nbd_device *lo, int lock)
121 /* Forcibly shutdown the socket causing all listeners
122 * to error
124 * FIXME: This code is duplicated from sys_shutdown, but
125 * there should be a more generic interface rather than
126 * calling socket ops directly here */
127 if (lock)
128 mutex_lock(&lo->tx_lock);
129 if (lo->sock) {
130 dev_warn(disk_to_dev(lo->disk), "shutting down socket\n");
131 kernel_sock_shutdown(lo->sock, SHUT_RDWR);
132 lo->sock = NULL;
134 if (lock)
135 mutex_unlock(&lo->tx_lock);
138 static void nbd_xmit_timeout(unsigned long arg)
140 struct task_struct *task = (struct task_struct *)arg;
142 printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n",
143 task->comm, task->pid);
144 force_sig(SIGKILL, task);
148 * Send or receive packet.
150 static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size,
151 int msg_flags)
153 struct socket *sock = lo->sock;
154 int result;
155 struct msghdr msg;
156 struct kvec iov;
157 sigset_t blocked, oldset;
159 if (unlikely(!sock)) {
160 dev_err(disk_to_dev(lo->disk),
161 "Attempted %s on closed socket in sock_xmit\n",
162 (send ? "send" : "recv"));
163 return -EINVAL;
166 /* Allow interception of SIGKILL only
167 * Don't allow other signals to interrupt the transmission */
168 siginitsetinv(&blocked, sigmask(SIGKILL));
169 sigprocmask(SIG_SETMASK, &blocked, &oldset);
171 do {
172 sock->sk->sk_allocation = GFP_NOIO;
173 iov.iov_base = buf;
174 iov.iov_len = size;
175 msg.msg_name = NULL;
176 msg.msg_namelen = 0;
177 msg.msg_control = NULL;
178 msg.msg_controllen = 0;
179 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
181 if (send) {
182 struct timer_list ti;
184 if (lo->xmit_timeout) {
185 init_timer(&ti);
186 ti.function = nbd_xmit_timeout;
187 ti.data = (unsigned long)current;
188 ti.expires = jiffies + lo->xmit_timeout;
189 add_timer(&ti);
191 result = kernel_sendmsg(sock, &msg, &iov, 1, size);
192 if (lo->xmit_timeout)
193 del_timer_sync(&ti);
194 } else
195 result = kernel_recvmsg(sock, &msg, &iov, 1, size,
196 msg.msg_flags);
198 if (signal_pending(current)) {
199 siginfo_t info;
200 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
201 task_pid_nr(current), current->comm,
202 dequeue_signal_lock(current, &current->blocked, &info));
203 result = -EINTR;
204 sock_shutdown(lo, !send);
205 break;
208 if (result <= 0) {
209 if (result == 0)
210 result = -EPIPE; /* short read */
211 break;
213 size -= result;
214 buf += result;
215 } while (size > 0);
217 sigprocmask(SIG_SETMASK, &oldset, NULL);
219 return result;
222 static inline int sock_send_bvec(struct nbd_device *lo, struct bio_vec *bvec,
223 int flags)
225 int result;
226 void *kaddr = kmap(bvec->bv_page);
227 result = sock_xmit(lo, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags);
228 kunmap(bvec->bv_page);
229 return result;
232 /* always call with the tx_lock held */
233 static int nbd_send_req(struct nbd_device *lo, struct request *req)
235 int result, flags;
236 struct nbd_request request;
237 unsigned long size = blk_rq_bytes(req);
239 request.magic = htonl(NBD_REQUEST_MAGIC);
240 request.type = htonl(nbd_cmd(req));
241 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
242 request.len = htonl(size);
243 memcpy(request.handle, &req, sizeof(req));
245 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n",
246 lo->disk->disk_name, req,
247 nbdcmd_to_ascii(nbd_cmd(req)),
248 (unsigned long long)blk_rq_pos(req) << 9,
249 blk_rq_bytes(req));
250 result = sock_xmit(lo, 1, &request, sizeof(request),
251 (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0);
252 if (result <= 0) {
253 dev_err(disk_to_dev(lo->disk),
254 "Send control failed (result %d)\n", result);
255 goto error_out;
258 if (nbd_cmd(req) == NBD_CMD_WRITE) {
259 struct req_iterator iter;
260 struct bio_vec *bvec;
262 * we are really probing at internals to determine
263 * whether to set MSG_MORE or not...
265 rq_for_each_segment(bvec, req, iter) {
266 flags = 0;
267 if (!rq_iter_last(req, iter))
268 flags = MSG_MORE;
269 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
270 lo->disk->disk_name, req, bvec->bv_len);
271 result = sock_send_bvec(lo, bvec, flags);
272 if (result <= 0) {
273 dev_err(disk_to_dev(lo->disk),
274 "Send data failed (result %d)\n",
275 result);
276 goto error_out;
280 return 0;
282 error_out:
283 return -EIO;
286 static struct request *nbd_find_request(struct nbd_device *lo,
287 struct request *xreq)
289 struct request *req, *tmp;
290 int err;
292 err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq);
293 if (unlikely(err))
294 goto out;
296 spin_lock(&lo->queue_lock);
297 list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) {
298 if (req != xreq)
299 continue;
300 list_del_init(&req->queuelist);
301 spin_unlock(&lo->queue_lock);
302 return req;
304 spin_unlock(&lo->queue_lock);
306 err = -ENOENT;
308 out:
309 return ERR_PTR(err);
312 static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec)
314 int result;
315 void *kaddr = kmap(bvec->bv_page);
316 result = sock_xmit(lo, 0, kaddr + bvec->bv_offset, bvec->bv_len,
317 MSG_WAITALL);
318 kunmap(bvec->bv_page);
319 return result;
322 /* NULL returned = something went wrong, inform userspace */
323 static struct request *nbd_read_stat(struct nbd_device *lo)
325 int result;
326 struct nbd_reply reply;
327 struct request *req;
329 reply.magic = 0;
330 result = sock_xmit(lo, 0, &reply, sizeof(reply), MSG_WAITALL);
331 if (result <= 0) {
332 dev_err(disk_to_dev(lo->disk),
333 "Receive control failed (result %d)\n", result);
334 goto harderror;
337 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
338 dev_err(disk_to_dev(lo->disk), "Wrong magic (0x%lx)\n",
339 (unsigned long)ntohl(reply.magic));
340 result = -EPROTO;
341 goto harderror;
344 req = nbd_find_request(lo, *(struct request **)reply.handle);
345 if (IS_ERR(req)) {
346 result = PTR_ERR(req);
347 if (result != -ENOENT)
348 goto harderror;
350 dev_err(disk_to_dev(lo->disk), "Unexpected reply (%p)\n",
351 reply.handle);
352 result = -EBADR;
353 goto harderror;
356 if (ntohl(reply.error)) {
357 dev_err(disk_to_dev(lo->disk), "Other side returned error (%d)\n",
358 ntohl(reply.error));
359 req->errors++;
360 return req;
363 dprintk(DBG_RX, "%s: request %p: got reply\n",
364 lo->disk->disk_name, req);
365 if (nbd_cmd(req) == NBD_CMD_READ) {
366 struct req_iterator iter;
367 struct bio_vec *bvec;
369 rq_for_each_segment(bvec, req, iter) {
370 result = sock_recv_bvec(lo, bvec);
371 if (result <= 0) {
372 dev_err(disk_to_dev(lo->disk), "Receive data failed (result %d)\n",
373 result);
374 req->errors++;
375 return req;
377 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
378 lo->disk->disk_name, req, bvec->bv_len);
381 return req;
382 harderror:
383 lo->harderror = result;
384 return NULL;
387 static ssize_t pid_show(struct device *dev,
388 struct device_attribute *attr, char *buf)
390 struct gendisk *disk = dev_to_disk(dev);
392 return sprintf(buf, "%ld\n",
393 (long) ((struct nbd_device *)disk->private_data)->pid);
396 static struct device_attribute pid_attr = {
397 .attr = { .name = "pid", .mode = S_IRUGO},
398 .show = pid_show,
401 static int nbd_do_it(struct nbd_device *lo)
403 struct request *req;
404 int ret;
406 BUG_ON(lo->magic != LO_MAGIC);
408 lo->pid = task_pid_nr(current);
409 ret = device_create_file(disk_to_dev(lo->disk), &pid_attr);
410 if (ret) {
411 dev_err(disk_to_dev(lo->disk), "device_create_file failed!\n");
412 lo->pid = 0;
413 return ret;
416 while ((req = nbd_read_stat(lo)) != NULL)
417 nbd_end_request(req);
419 device_remove_file(disk_to_dev(lo->disk), &pid_attr);
420 lo->pid = 0;
421 return 0;
424 static void nbd_clear_que(struct nbd_device *lo)
426 struct request *req;
428 BUG_ON(lo->magic != LO_MAGIC);
431 * Because we have set lo->sock to NULL under the tx_lock, all
432 * modifications to the list must have completed by now. For
433 * the same reason, the active_req must be NULL.
435 * As a consequence, we don't need to take the spin lock while
436 * purging the list here.
438 BUG_ON(lo->sock);
439 BUG_ON(lo->active_req);
441 while (!list_empty(&lo->queue_head)) {
442 req = list_entry(lo->queue_head.next, struct request,
443 queuelist);
444 list_del_init(&req->queuelist);
445 req->errors++;
446 nbd_end_request(req);
451 static void nbd_handle_req(struct nbd_device *lo, struct request *req)
453 if (req->cmd_type != REQ_TYPE_FS)
454 goto error_out;
456 nbd_cmd(req) = NBD_CMD_READ;
457 if (rq_data_dir(req) == WRITE) {
458 nbd_cmd(req) = NBD_CMD_WRITE;
459 if (lo->flags & NBD_READ_ONLY) {
460 dev_err(disk_to_dev(lo->disk),
461 "Write on read-only\n");
462 goto error_out;
466 req->errors = 0;
468 mutex_lock(&lo->tx_lock);
469 if (unlikely(!lo->sock)) {
470 mutex_unlock(&lo->tx_lock);
471 dev_err(disk_to_dev(lo->disk),
472 "Attempted send on closed socket\n");
473 goto error_out;
476 lo->active_req = req;
478 if (nbd_send_req(lo, req) != 0) {
479 dev_err(disk_to_dev(lo->disk), "Request send failed\n");
480 req->errors++;
481 nbd_end_request(req);
482 } else {
483 spin_lock(&lo->queue_lock);
484 list_add(&req->queuelist, &lo->queue_head);
485 spin_unlock(&lo->queue_lock);
488 lo->active_req = NULL;
489 mutex_unlock(&lo->tx_lock);
490 wake_up_all(&lo->active_wq);
492 return;
494 error_out:
495 req->errors++;
496 nbd_end_request(req);
499 static int nbd_thread(void *data)
501 struct nbd_device *lo = data;
502 struct request *req;
504 set_user_nice(current, -20);
505 while (!kthread_should_stop() || !list_empty(&lo->waiting_queue)) {
506 /* wait for something to do */
507 wait_event_interruptible(lo->waiting_wq,
508 kthread_should_stop() ||
509 !list_empty(&lo->waiting_queue));
511 /* extract request */
512 if (list_empty(&lo->waiting_queue))
513 continue;
515 spin_lock_irq(&lo->queue_lock);
516 req = list_entry(lo->waiting_queue.next, struct request,
517 queuelist);
518 list_del_init(&req->queuelist);
519 spin_unlock_irq(&lo->queue_lock);
521 /* handle request */
522 nbd_handle_req(lo, req);
524 return 0;
528 * We always wait for result of write, for now. It would be nice to make it optional
529 * in future
530 * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK))
531 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); }
534 static void do_nbd_request(struct request_queue *q)
536 struct request *req;
538 while ((req = blk_fetch_request(q)) != NULL) {
539 struct nbd_device *lo;
541 spin_unlock_irq(q->queue_lock);
543 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n",
544 req->rq_disk->disk_name, req, req->cmd_type);
546 lo = req->rq_disk->private_data;
548 BUG_ON(lo->magic != LO_MAGIC);
550 if (unlikely(!lo->sock)) {
551 dev_err(disk_to_dev(lo->disk),
552 "Attempted send on closed socket\n");
553 req->errors++;
554 nbd_end_request(req);
555 spin_lock_irq(q->queue_lock);
556 continue;
559 spin_lock_irq(&lo->queue_lock);
560 list_add_tail(&req->queuelist, &lo->waiting_queue);
561 spin_unlock_irq(&lo->queue_lock);
563 wake_up(&lo->waiting_wq);
565 spin_lock_irq(q->queue_lock);
569 /* Must be called with tx_lock held */
571 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *lo,
572 unsigned int cmd, unsigned long arg)
574 switch (cmd) {
575 case NBD_DISCONNECT: {
576 struct request sreq;
578 dev_info(disk_to_dev(lo->disk), "NBD_DISCONNECT\n");
580 blk_rq_init(NULL, &sreq);
581 sreq.cmd_type = REQ_TYPE_SPECIAL;
582 nbd_cmd(&sreq) = NBD_CMD_DISC;
583 if (!lo->sock)
584 return -EINVAL;
585 nbd_send_req(lo, &sreq);
586 return 0;
589 case NBD_CLEAR_SOCK: {
590 struct file *file;
592 lo->sock = NULL;
593 file = lo->file;
594 lo->file = NULL;
595 nbd_clear_que(lo);
596 BUG_ON(!list_empty(&lo->queue_head));
597 if (file)
598 fput(file);
599 return 0;
602 case NBD_SET_SOCK: {
603 struct file *file;
604 if (lo->file)
605 return -EBUSY;
606 file = fget(arg);
607 if (file) {
608 struct inode *inode = file->f_path.dentry->d_inode;
609 if (S_ISSOCK(inode->i_mode)) {
610 lo->file = file;
611 lo->sock = SOCKET_I(inode);
612 if (max_part > 0)
613 bdev->bd_invalidated = 1;
614 return 0;
615 } else {
616 fput(file);
619 return -EINVAL;
622 case NBD_SET_BLKSIZE:
623 lo->blksize = arg;
624 lo->bytesize &= ~(lo->blksize-1);
625 bdev->bd_inode->i_size = lo->bytesize;
626 set_blocksize(bdev, lo->blksize);
627 set_capacity(lo->disk, lo->bytesize >> 9);
628 return 0;
630 case NBD_SET_SIZE:
631 lo->bytesize = arg & ~(lo->blksize-1);
632 bdev->bd_inode->i_size = lo->bytesize;
633 set_blocksize(bdev, lo->blksize);
634 set_capacity(lo->disk, lo->bytesize >> 9);
635 return 0;
637 case NBD_SET_TIMEOUT:
638 lo->xmit_timeout = arg * HZ;
639 return 0;
641 case NBD_SET_SIZE_BLOCKS:
642 lo->bytesize = ((u64) arg) * lo->blksize;
643 bdev->bd_inode->i_size = lo->bytesize;
644 set_blocksize(bdev, lo->blksize);
645 set_capacity(lo->disk, lo->bytesize >> 9);
646 return 0;
648 case NBD_DO_IT: {
649 struct task_struct *thread;
650 struct file *file;
651 int error;
653 if (lo->pid)
654 return -EBUSY;
655 if (!lo->file)
656 return -EINVAL;
658 mutex_unlock(&lo->tx_lock);
660 thread = kthread_create(nbd_thread, lo, lo->disk->disk_name);
661 if (IS_ERR(thread)) {
662 mutex_lock(&lo->tx_lock);
663 return PTR_ERR(thread);
665 wake_up_process(thread);
666 error = nbd_do_it(lo);
667 kthread_stop(thread);
669 mutex_lock(&lo->tx_lock);
670 if (error)
671 return error;
672 sock_shutdown(lo, 0);
673 file = lo->file;
674 lo->file = NULL;
675 nbd_clear_que(lo);
676 dev_warn(disk_to_dev(lo->disk), "queue cleared\n");
677 if (file)
678 fput(file);
679 lo->bytesize = 0;
680 bdev->bd_inode->i_size = 0;
681 set_capacity(lo->disk, 0);
682 if (max_part > 0)
683 ioctl_by_bdev(bdev, BLKRRPART, 0);
684 return lo->harderror;
687 case NBD_CLEAR_QUE:
689 * This is for compatibility only. The queue is always cleared
690 * by NBD_DO_IT or NBD_CLEAR_SOCK.
692 BUG_ON(!lo->sock && !list_empty(&lo->queue_head));
693 return 0;
695 case NBD_PRINT_DEBUG:
696 dev_info(disk_to_dev(lo->disk),
697 "next = %p, prev = %p, head = %p\n",
698 lo->queue_head.next, lo->queue_head.prev,
699 &lo->queue_head);
700 return 0;
702 return -ENOTTY;
705 static int nbd_ioctl(struct block_device *bdev, fmode_t mode,
706 unsigned int cmd, unsigned long arg)
708 struct nbd_device *lo = bdev->bd_disk->private_data;
709 int error;
711 if (!capable(CAP_SYS_ADMIN))
712 return -EPERM;
714 BUG_ON(lo->magic != LO_MAGIC);
716 /* Anyone capable of this syscall can do *real bad* things */
717 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
718 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
720 mutex_lock(&lo->tx_lock);
721 error = __nbd_ioctl(bdev, lo, cmd, arg);
722 mutex_unlock(&lo->tx_lock);
724 return error;
727 static const struct block_device_operations nbd_fops =
729 .owner = THIS_MODULE,
730 .ioctl = nbd_ioctl,
734 * And here should be modules and kernel interface
735 * (Just smiley confuses emacs :-)
738 static int __init nbd_init(void)
740 int err = -ENOMEM;
741 int i;
742 int part_shift;
744 BUILD_BUG_ON(sizeof(struct nbd_request) != 28);
746 if (max_part < 0) {
747 printk(KERN_ERR "nbd: max_part must be >= 0\n");
748 return -EINVAL;
751 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL);
752 if (!nbd_dev)
753 return -ENOMEM;
755 part_shift = 0;
756 if (max_part > 0) {
757 part_shift = fls(max_part);
760 * Adjust max_part according to part_shift as it is exported
761 * to user space so that user can know the max number of
762 * partition kernel should be able to manage.
764 * Note that -1 is required because partition 0 is reserved
765 * for the whole disk.
767 max_part = (1UL << part_shift) - 1;
770 if ((1UL << part_shift) > DISK_MAX_PARTS)
771 return -EINVAL;
773 if (nbds_max > 1UL << (MINORBITS - part_shift))
774 return -EINVAL;
776 for (i = 0; i < nbds_max; i++) {
777 struct gendisk *disk = alloc_disk(1 << part_shift);
778 if (!disk)
779 goto out;
780 nbd_dev[i].disk = disk;
782 * The new linux 2.5 block layer implementation requires
783 * every gendisk to have its very own request_queue struct.
784 * These structs are big so we dynamically allocate them.
786 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock);
787 if (!disk->queue) {
788 put_disk(disk);
789 goto out;
792 * Tell the block layer that we are not a rotational device
794 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue);
797 if (register_blkdev(NBD_MAJOR, "nbd")) {
798 err = -EIO;
799 goto out;
802 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
803 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
805 for (i = 0; i < nbds_max; i++) {
806 struct gendisk *disk = nbd_dev[i].disk;
807 nbd_dev[i].file = NULL;
808 nbd_dev[i].magic = LO_MAGIC;
809 nbd_dev[i].flags = 0;
810 INIT_LIST_HEAD(&nbd_dev[i].waiting_queue);
811 spin_lock_init(&nbd_dev[i].queue_lock);
812 INIT_LIST_HEAD(&nbd_dev[i].queue_head);
813 mutex_init(&nbd_dev[i].tx_lock);
814 init_waitqueue_head(&nbd_dev[i].active_wq);
815 init_waitqueue_head(&nbd_dev[i].waiting_wq);
816 nbd_dev[i].blksize = 1024;
817 nbd_dev[i].bytesize = 0;
818 disk->major = NBD_MAJOR;
819 disk->first_minor = i << part_shift;
820 disk->fops = &nbd_fops;
821 disk->private_data = &nbd_dev[i];
822 sprintf(disk->disk_name, "nbd%d", i);
823 set_capacity(disk, 0);
824 add_disk(disk);
827 return 0;
828 out:
829 while (i--) {
830 blk_cleanup_queue(nbd_dev[i].disk->queue);
831 put_disk(nbd_dev[i].disk);
833 kfree(nbd_dev);
834 return err;
837 static void __exit nbd_cleanup(void)
839 int i;
840 for (i = 0; i < nbds_max; i++) {
841 struct gendisk *disk = nbd_dev[i].disk;
842 nbd_dev[i].magic = 0;
843 if (disk) {
844 del_gendisk(disk);
845 blk_cleanup_queue(disk->queue);
846 put_disk(disk);
849 unregister_blkdev(NBD_MAJOR, "nbd");
850 kfree(nbd_dev);
851 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
854 module_init(nbd_init);
855 module_exit(nbd_cleanup);
857 MODULE_DESCRIPTION("Network Block Device");
858 MODULE_LICENSE("GPL");
860 module_param(nbds_max, int, 0444);
861 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)");
862 module_param(max_part, int, 0444);
863 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)");
864 #ifndef NDEBUG
865 module_param(debugflags, int, 0644);
866 MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
867 #endif