blob: efdf04450bf731c37177b1c12ef993ee43c84659 [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 *
7 * Copyright 1997-2000 Pavel Machek <pavel@ucw.cz>
8 * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com>
9 *
10 * (part of code stolen from loop.c)
11 *
12 * 97-3-25 compiled 0-th version, not yet tested it
13 * (it did not work, BTW) (later that day) HEY! it works!
14 * (bit later) hmm, not that much... 2:00am next day:
15 * yes, it works, but it gives something like 50kB/sec
16 * 97-4-01 complete rewrite to make it possible for many requests at
17 * once to be processed
18 * 97-4-11 Making protocol independent of endianity etc.
19 * 97-9-13 Cosmetic changes
20 * 98-5-13 Attempt to make 64-bit-clean on 64-bit machines
21 * 99-1-11 Attempt to make 64-bit-clean on 32-bit machines <ankry@mif.pg.gda.pl>
22 * 01-2-27 Fix to store proper blockcount for kernel (calculated using
23 * BLOCK_SIZE_BITS, not device blocksize) <aga@permonline.ru>
24 * 01-3-11 Make nbd work with new Linux block layer code. It now supports
25 * plugging like all the other block devices. Also added in MSG_MORE to
26 * reduce number of partial TCP segments sent. <steve@chygwyn.com>
27 * 01-12-6 Fix deadlock condition by making queue locks independent of
28 * the transmit lock. <steve@chygwyn.com>
29 * 02-10-11 Allow hung xmit to be aborted via SIGKILL & various fixes.
30 * <Paul.Clements@SteelEye.com> <James.Bottomley@SteelEye.com>
31 * 03-06-22 Make nbd work with new linux 2.5 block layer design. This fixes
32 * memory corruption from module removal and possible memory corruption
33 * from sending/receiving disk data. <ldl@aros.net>
34 * 03-06-23 Cosmetic changes. <ldl@aros.net>
35 * 03-06-23 Enhance diagnostics support. <ldl@aros.net>
36 * 03-06-24 Remove unneeded blksize_bits field from nbd_device struct.
37 * <ldl@aros.net>
38 * 03-06-24 Cleanup PARANOIA usage & code. <ldl@aros.net>
39 * 04-02-19 Remove PARANOIA, plus various cleanups (Paul Clements)
40 * possible FIXME: make set_sock / set_blksize / set_size / do_it one syscall
41 * why not: would need access_ok and friends, would share yet another
42 * structure with userland
43 */
44
45#include <linux/major.h>
46
47#include <linux/blkdev.h>
48#include <linux/module.h>
49#include <linux/init.h>
50#include <linux/sched.h>
51#include <linux/fs.h>
52#include <linux/bio.h>
53#include <linux/stat.h>
54#include <linux/errno.h>
55#include <linux/file.h>
56#include <linux/ioctl.h>
57#include <net/sock.h>
58
59#include <linux/devfs_fs_kernel.h>
60
61#include <asm/uaccess.h>
62#include <asm/types.h>
63
64#include <linux/nbd.h>
65
66#define LO_MAGIC 0x68797548
67
68#ifdef NDEBUG
69#define dprintk(flags, fmt...)
70#else /* NDEBUG */
71#define dprintk(flags, fmt...) do { \
72 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \
73} while (0)
74#define DBG_IOCTL 0x0004
75#define DBG_INIT 0x0010
76#define DBG_EXIT 0x0020
77#define DBG_BLKDEV 0x0100
78#define DBG_RX 0x0200
79#define DBG_TX 0x0400
80static unsigned int debugflags;
81#endif /* NDEBUG */
82
83static struct nbd_device nbd_dev[MAX_NBD];
84
85/*
86 * Use just one lock (or at most 1 per NIC). Two arguments for this:
87 * 1. Each NIC is essentially a synchronization point for all servers
88 * accessed through that NIC so there's no need to have more locks
89 * than NICs anyway.
90 * 2. More locks lead to more "Dirty cache line bouncing" which will slow
91 * down each lock to the point where they're actually slower than just
92 * a single lock.
93 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this!
94 */
95static DEFINE_SPINLOCK(nbd_lock);
96
97#ifndef NDEBUG
98static const char *ioctl_cmd_to_ascii(int cmd)
99{
100 switch (cmd) {
101 case NBD_SET_SOCK: return "set-sock";
102 case NBD_SET_BLKSIZE: return "set-blksize";
103 case NBD_SET_SIZE: return "set-size";
104 case NBD_DO_IT: return "do-it";
105 case NBD_CLEAR_SOCK: return "clear-sock";
106 case NBD_CLEAR_QUE: return "clear-que";
107 case NBD_PRINT_DEBUG: return "print-debug";
108 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks";
109 case NBD_DISCONNECT: return "disconnect";
110 case BLKROSET: return "set-read-only";
111 case BLKFLSBUF: return "flush-buffer-cache";
112 }
113 return "unknown";
114}
115
116static const char *nbdcmd_to_ascii(int cmd)
117{
118 switch (cmd) {
119 case NBD_CMD_READ: return "read";
120 case NBD_CMD_WRITE: return "write";
121 case NBD_CMD_DISC: return "disconnect";
122 }
123 return "invalid";
124}
125#endif /* NDEBUG */
126
127static void nbd_end_request(struct request *req)
128{
129 int uptodate = (req->errors == 0) ? 1 : 0;
130 request_queue_t *q = req->q;
131 unsigned long flags;
132
133 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name,
134 req, uptodate? "done": "failed");
135
136 spin_lock_irqsave(q->queue_lock, flags);
137 if (!end_that_request_first(req, uptodate, req->nr_sectors)) {
138 end_that_request_last(req);
139 }
140 spin_unlock_irqrestore(q->queue_lock, flags);
141}
142
143/*
144 * Send or receive packet.
145 */
146static int sock_xmit(struct socket *sock, int send, void *buf, int size,
147 int msg_flags)
148{
149 int result;
150 struct msghdr msg;
151 struct kvec iov;
152 unsigned long flags;
153 sigset_t oldset;
154
155 /* Allow interception of SIGKILL only
156 * Don't allow other signals to interrupt the transmission */
157 spin_lock_irqsave(&current->sighand->siglock, flags);
158 oldset = current->blocked;
159 sigfillset(&current->blocked);
160 sigdelsetmask(&current->blocked, sigmask(SIGKILL));
161 recalc_sigpending();
162 spin_unlock_irqrestore(&current->sighand->siglock, flags);
163
164 do {
165 sock->sk->sk_allocation = GFP_NOIO;
166 iov.iov_base = buf;
167 iov.iov_len = size;
168 msg.msg_name = NULL;
169 msg.msg_namelen = 0;
170 msg.msg_control = NULL;
171 msg.msg_controllen = 0;
172 msg.msg_namelen = 0;
173 msg.msg_flags = msg_flags | MSG_NOSIGNAL;
174
175 if (send)
176 result = kernel_sendmsg(sock, &msg, &iov, 1, size);
177 else
178 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0);
179
180 if (signal_pending(current)) {
181 siginfo_t info;
182 spin_lock_irqsave(&current->sighand->siglock, flags);
183 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n",
184 current->pid, current->comm,
185 dequeue_signal(current, &current->blocked, &info));
186 spin_unlock_irqrestore(&current->sighand->siglock, flags);
187 result = -EINTR;
188 break;
189 }
190
191 if (result <= 0) {
192 if (result == 0)
193 result = -EPIPE; /* short read */
194 break;
195 }
196 size -= result;
197 buf += result;
198 } while (size > 0);
199
200 spin_lock_irqsave(&current->sighand->siglock, flags);
201 current->blocked = oldset;
202 recalc_sigpending();
203 spin_unlock_irqrestore(&current->sighand->siglock, flags);
204
205 return result;
206}
207
208static inline int sock_send_bvec(struct socket *sock, struct bio_vec *bvec,
209 int flags)
210{
211 int result;
212 void *kaddr = kmap(bvec->bv_page);
213 result = sock_xmit(sock, 1, kaddr + bvec->bv_offset, bvec->bv_len,
214 flags);
215 kunmap(bvec->bv_page);
216 return result;
217}
218
219static int nbd_send_req(struct nbd_device *lo, struct request *req)
220{
221 int result, i, flags;
222 struct nbd_request request;
223 unsigned long size = req->nr_sectors << 9;
224 struct socket *sock = lo->sock;
225
226 request.magic = htonl(NBD_REQUEST_MAGIC);
227 request.type = htonl(nbd_cmd(req));
228 request.from = cpu_to_be64((u64) req->sector << 9);
229 request.len = htonl(size);
230 memcpy(request.handle, &req, sizeof(req));
231
232 down(&lo->tx_lock);
233
234 if (!sock || !lo->sock) {
235 printk(KERN_ERR "%s: Attempted send on closed socket\n",
236 lo->disk->disk_name);
237 goto error_out;
238 }
239
240 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n",
241 lo->disk->disk_name, req,
242 nbdcmd_to_ascii(nbd_cmd(req)),
243 (unsigned long long)req->sector << 9,
244 req->nr_sectors << 9);
245 result = sock_xmit(sock, 1, &request, sizeof(request),
246 (nbd_cmd(req) == NBD_CMD_WRITE)? MSG_MORE: 0);
247 if (result <= 0) {
248 printk(KERN_ERR "%s: Send control failed (result %d)\n",
249 lo->disk->disk_name, result);
250 goto error_out;
251 }
252
253 if (nbd_cmd(req) == NBD_CMD_WRITE) {
254 struct bio *bio;
255 /*
256 * we are really probing at internals to determine
257 * whether to set MSG_MORE or not...
258 */
259 rq_for_each_bio(bio, req) {
260 struct bio_vec *bvec;
261 bio_for_each_segment(bvec, bio, i) {
262 flags = 0;
263 if ((i < (bio->bi_vcnt - 1)) || bio->bi_next)
264 flags = MSG_MORE;
265 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
266 lo->disk->disk_name, req,
267 bvec->bv_len);
268 result = sock_send_bvec(sock, bvec, flags);
269 if (result <= 0) {
270 printk(KERN_ERR "%s: Send data failed (result %d)\n",
271 lo->disk->disk_name,
272 result);
273 goto error_out;
274 }
275 }
276 }
277 }
278 up(&lo->tx_lock);
279 return 0;
280
281error_out:
282 up(&lo->tx_lock);
283 return 1;
284}
285
286static struct request *nbd_find_request(struct nbd_device *lo, char *handle)
287{
288 struct request *req;
289 struct list_head *tmp;
290 struct request *xreq;
291
292 memcpy(&xreq, handle, sizeof(xreq));
293
294 spin_lock(&lo->queue_lock);
295 list_for_each(tmp, &lo->queue_head) {
296 req = list_entry(tmp, struct request, queuelist);
297 if (req != xreq)
298 continue;
299 list_del_init(&req->queuelist);
300 spin_unlock(&lo->queue_lock);
301 return req;
302 }
303 spin_unlock(&lo->queue_lock);
304 return NULL;
305}
306
307static inline int sock_recv_bvec(struct socket *sock, struct bio_vec *bvec)
308{
309 int result;
310 void *kaddr = kmap(bvec->bv_page);
311 result = sock_xmit(sock, 0, kaddr + bvec->bv_offset, bvec->bv_len,
312 MSG_WAITALL);
313 kunmap(bvec->bv_page);
314 return result;
315}
316
317/* NULL returned = something went wrong, inform userspace */
318static struct request *nbd_read_stat(struct nbd_device *lo)
319{
320 int result;
321 struct nbd_reply reply;
322 struct request *req;
323 struct socket *sock = lo->sock;
324
325 reply.magic = 0;
326 result = sock_xmit(sock, 0, &reply, sizeof(reply), MSG_WAITALL);
327 if (result <= 0) {
328 printk(KERN_ERR "%s: Receive control failed (result %d)\n",
329 lo->disk->disk_name, result);
330 goto harderror;
331 }
332 req = nbd_find_request(lo, reply.handle);
333 if (req == NULL) {
334 printk(KERN_ERR "%s: Unexpected reply (%p)\n",
335 lo->disk->disk_name, reply.handle);
336 result = -EBADR;
337 goto harderror;
338 }
339
340 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) {
341 printk(KERN_ERR "%s: Wrong magic (0x%lx)\n",
342 lo->disk->disk_name,
343 (unsigned long)ntohl(reply.magic));
344 result = -EPROTO;
345 goto harderror;
346 }
347 if (ntohl(reply.error)) {
348 printk(KERN_ERR "%s: Other side returned error (%d)\n",
349 lo->disk->disk_name, ntohl(reply.error));
350 req->errors++;
351 return req;
352 }
353
354 dprintk(DBG_RX, "%s: request %p: got reply\n",
355 lo->disk->disk_name, req);
356 if (nbd_cmd(req) == NBD_CMD_READ) {
357 int i;
358 struct bio *bio;
359 rq_for_each_bio(bio, req) {
360 struct bio_vec *bvec;
361 bio_for_each_segment(bvec, bio, i) {
362 result = sock_recv_bvec(sock, bvec);
363 if (result <= 0) {
364 printk(KERN_ERR "%s: Receive data failed (result %d)\n",
365 lo->disk->disk_name,
366 result);
367 goto harderror;
368 }
369 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
370 lo->disk->disk_name, req, bvec->bv_len);
371 }
372 }
373 }
374 return req;
375harderror:
376 lo->harderror = result;
377 return NULL;
378}
379
380static void nbd_do_it(struct nbd_device *lo)
381{
382 struct request *req;
383
384 BUG_ON(lo->magic != LO_MAGIC);
385
386 while ((req = nbd_read_stat(lo)) != NULL)
387 nbd_end_request(req);
388 return;
389}
390
391static void nbd_clear_que(struct nbd_device *lo)
392{
393 struct request *req;
394
395 BUG_ON(lo->magic != LO_MAGIC);
396
397 do {
398 req = NULL;
399 spin_lock(&lo->queue_lock);
400 if (!list_empty(&lo->queue_head)) {
401 req = list_entry(lo->queue_head.next, struct request, queuelist);
402 list_del_init(&req->queuelist);
403 }
404 spin_unlock(&lo->queue_lock);
405 if (req) {
406 req->errors++;
407 nbd_end_request(req);
408 }
409 } while (req);
410}
411
412/*
413 * We always wait for result of write, for now. It would be nice to make it optional
414 * in future
415 * if ((req->cmd == WRITE) && (lo->flags & NBD_WRITE_NOCHK))
416 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); }
417 */
418
419static void do_nbd_request(request_queue_t * q)
420{
421 struct request *req;
422
423 while ((req = elv_next_request(q)) != NULL) {
424 struct nbd_device *lo;
425
426 blkdev_dequeue_request(req);
427 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%lx)\n",
428 req->rq_disk->disk_name, req, req->flags);
429
430 if (!(req->flags & REQ_CMD))
431 goto error_out;
432
433 lo = req->rq_disk->private_data;
434
435 BUG_ON(lo->magic != LO_MAGIC);
436
437 if (!lo->file) {
438 printk(KERN_ERR "%s: Request when not-ready\n",
439 lo->disk->disk_name);
440 goto error_out;
441 }
442 nbd_cmd(req) = NBD_CMD_READ;
443 if (rq_data_dir(req) == WRITE) {
444 nbd_cmd(req) = NBD_CMD_WRITE;
445 if (lo->flags & NBD_READ_ONLY) {
446 printk(KERN_ERR "%s: Write on read-only\n",
447 lo->disk->disk_name);
448 goto error_out;
449 }
450 }
451
452 req->errors = 0;
453 spin_unlock_irq(q->queue_lock);
454
455 spin_lock(&lo->queue_lock);
456
457 if (!lo->file) {
458 spin_unlock(&lo->queue_lock);
459 printk(KERN_ERR "%s: failed between accept and semaphore, file lost\n",
460 lo->disk->disk_name);
461 req->errors++;
462 nbd_end_request(req);
463 spin_lock_irq(q->queue_lock);
464 continue;
465 }
466
467 list_add(&req->queuelist, &lo->queue_head);
468 spin_unlock(&lo->queue_lock);
469
470 if (nbd_send_req(lo, req) != 0) {
471 printk(KERN_ERR "%s: Request send failed\n",
472 lo->disk->disk_name);
473 if (nbd_find_request(lo, (char *)&req) != NULL) {
474 /* we still own req */
475 req->errors++;
476 nbd_end_request(req);
477 } else /* we're racing with nbd_clear_que */
478 printk(KERN_DEBUG "nbd: can't find req\n");
479 }
480
481 spin_lock_irq(q->queue_lock);
482 continue;
483
484error_out:
485 req->errors++;
486 spin_unlock(q->queue_lock);
487 nbd_end_request(req);
488 spin_lock(q->queue_lock);
489 }
490 return;
491}
492
493static int nbd_ioctl(struct inode *inode, struct file *file,
494 unsigned int cmd, unsigned long arg)
495{
496 struct nbd_device *lo = inode->i_bdev->bd_disk->private_data;
497 int error;
498 struct request sreq ;
499
500 if (!capable(CAP_SYS_ADMIN))
501 return -EPERM;
502
503 BUG_ON(lo->magic != LO_MAGIC);
504
505 /* Anyone capable of this syscall can do *real bad* things */
506 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
507 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
508
509 switch (cmd) {
510 case NBD_DISCONNECT:
511 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name);
512 sreq.flags = REQ_SPECIAL;
513 nbd_cmd(&sreq) = NBD_CMD_DISC;
514 /*
515 * Set these to sane values in case server implementation
516 * fails to check the request type first and also to keep
517 * debugging output cleaner.
518 */
519 sreq.sector = 0;
520 sreq.nr_sectors = 0;
521 if (!lo->sock)
522 return -EINVAL;
523 nbd_send_req(lo, &sreq);
524 return 0;
525
526 case NBD_CLEAR_SOCK:
527 error = 0;
528 down(&lo->tx_lock);
529 lo->sock = NULL;
530 up(&lo->tx_lock);
531 spin_lock(&lo->queue_lock);
532 file = lo->file;
533 lo->file = NULL;
534 spin_unlock(&lo->queue_lock);
535 nbd_clear_que(lo);
536 spin_lock(&lo->queue_lock);
537 if (!list_empty(&lo->queue_head)) {
538 printk(KERN_ERR "nbd: disconnect: some requests are in progress -> please try again.\n");
539 error = -EBUSY;
540 }
541 spin_unlock(&lo->queue_lock);
542 if (file)
543 fput(file);
544 return error;
545 case NBD_SET_SOCK:
546 if (lo->file)
547 return -EBUSY;
548 error = -EINVAL;
549 file = fget(arg);
550 if (file) {
551 inode = file->f_dentry->d_inode;
552 if (S_ISSOCK(inode->i_mode)) {
553 lo->file = file;
554 lo->sock = SOCKET_I(inode);
555 error = 0;
556 } else {
557 fput(file);
558 }
559 }
560 return error;
561 case NBD_SET_BLKSIZE:
562 lo->blksize = arg;
563 lo->bytesize &= ~(lo->blksize-1);
564 inode->i_bdev->bd_inode->i_size = lo->bytesize;
565 set_blocksize(inode->i_bdev, lo->blksize);
566 set_capacity(lo->disk, lo->bytesize >> 9);
567 return 0;
568 case NBD_SET_SIZE:
569 lo->bytesize = arg & ~(lo->blksize-1);
570 inode->i_bdev->bd_inode->i_size = lo->bytesize;
571 set_blocksize(inode->i_bdev, lo->blksize);
572 set_capacity(lo->disk, lo->bytesize >> 9);
573 return 0;
574 case NBD_SET_SIZE_BLOCKS:
575 lo->bytesize = ((u64) arg) * lo->blksize;
576 inode->i_bdev->bd_inode->i_size = lo->bytesize;
577 set_blocksize(inode->i_bdev, lo->blksize);
578 set_capacity(lo->disk, lo->bytesize >> 9);
579 return 0;
580 case NBD_DO_IT:
581 if (!lo->file)
582 return -EINVAL;
583 nbd_do_it(lo);
584 /* on return tidy up in case we have a signal */
585 /* Forcibly shutdown the socket causing all listeners
586 * to error
587 *
588 * FIXME: This code is duplicated from sys_shutdown, but
589 * there should be a more generic interface rather than
590 * calling socket ops directly here */
591 down(&lo->tx_lock);
592 if (lo->sock) {
593 printk(KERN_WARNING "%s: shutting down socket\n",
594 lo->disk->disk_name);
595 lo->sock->ops->shutdown(lo->sock,
596 SEND_SHUTDOWN|RCV_SHUTDOWN);
597 lo->sock = NULL;
598 }
599 up(&lo->tx_lock);
600 spin_lock(&lo->queue_lock);
601 file = lo->file;
602 lo->file = NULL;
603 spin_unlock(&lo->queue_lock);
604 nbd_clear_que(lo);
605 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name);
606 if (file)
607 fput(file);
608 return lo->harderror;
609 case NBD_CLEAR_QUE:
610 down(&lo->tx_lock);
611 if (lo->sock) {
612 up(&lo->tx_lock);
613 return 0; /* probably should be error, but that would
614 * break "nbd-client -d", so just return 0 */
615 }
616 up(&lo->tx_lock);
617 nbd_clear_que(lo);
618 return 0;
619 case NBD_PRINT_DEBUG:
620 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n",
621 inode->i_bdev->bd_disk->disk_name,
622 lo->queue_head.next, lo->queue_head.prev,
623 &lo->queue_head);
624 return 0;
625 }
626 return -EINVAL;
627}
628
629static struct block_device_operations nbd_fops =
630{
631 .owner = THIS_MODULE,
632 .ioctl = nbd_ioctl,
633};
634
635/*
636 * And here should be modules and kernel interface
637 * (Just smiley confuses emacs :-)
638 */
639
640static int __init nbd_init(void)
641{
642 int err = -ENOMEM;
643 int i;
644
645 if (sizeof(struct nbd_request) != 28) {
646 printk(KERN_CRIT "nbd: sizeof nbd_request needs to be 28 in order to work!\n" );
647 return -EIO;
648 }
649
650 for (i = 0; i < MAX_NBD; i++) {
651 struct gendisk *disk = alloc_disk(1);
652 if (!disk)
653 goto out;
654 nbd_dev[i].disk = disk;
655 /*
656 * The new linux 2.5 block layer implementation requires
657 * every gendisk to have its very own request_queue struct.
658 * These structs are big so we dynamically allocate them.
659 */
660 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock);
661 if (!disk->queue) {
662 put_disk(disk);
663 goto out;
664 }
665 }
666
667 if (register_blkdev(NBD_MAJOR, "nbd")) {
668 err = -EIO;
669 goto out;
670 }
671
672 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR);
673 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags);
674
675 devfs_mk_dir("nbd");
676 for (i = 0; i < MAX_NBD; i++) {
677 struct gendisk *disk = nbd_dev[i].disk;
678 nbd_dev[i].file = NULL;
679 nbd_dev[i].magic = LO_MAGIC;
680 nbd_dev[i].flags = 0;
681 spin_lock_init(&nbd_dev[i].queue_lock);
682 INIT_LIST_HEAD(&nbd_dev[i].queue_head);
683 init_MUTEX(&nbd_dev[i].tx_lock);
684 nbd_dev[i].blksize = 1024;
685 nbd_dev[i].bytesize = 0x7ffffc00ULL << 10; /* 2TB */
686 disk->major = NBD_MAJOR;
687 disk->first_minor = i;
688 disk->fops = &nbd_fops;
689 disk->private_data = &nbd_dev[i];
690 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
691 sprintf(disk->disk_name, "nbd%d", i);
692 sprintf(disk->devfs_name, "nbd/%d", i);
693 set_capacity(disk, 0x7ffffc00ULL << 1); /* 2 TB */
694 add_disk(disk);
695 }
696
697 return 0;
698out:
699 while (i--) {
700 blk_cleanup_queue(nbd_dev[i].disk->queue);
701 put_disk(nbd_dev[i].disk);
702 }
703 return err;
704}
705
706static void __exit nbd_cleanup(void)
707{
708 int i;
709 for (i = 0; i < MAX_NBD; i++) {
710 struct gendisk *disk = nbd_dev[i].disk;
711 if (disk) {
712 del_gendisk(disk);
713 blk_cleanup_queue(disk->queue);
714 put_disk(disk);
715 }
716 }
717 devfs_remove("nbd");
718 unregister_blkdev(NBD_MAJOR, "nbd");
719 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR);
720}
721
722module_init(nbd_init);
723module_exit(nbd_cleanup);
724
725MODULE_DESCRIPTION("Network Block Device");
726MODULE_LICENSE("GPL");
727
728#ifndef NDEBUG
729module_param(debugflags, int, 0644);
730MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
731#endif