1 /* 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 * This file is released under GPLv2 or later. 11 * 12 * (part of code stolen from loop.c) 13 */ 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> 27 #include <linux/compiler.h> 28 #include <linux/err.h> 29 #include <linux/kernel.h> 30 #include <net/sock.h> 31 32 #include <asm/uaccess.h> 33 #include <asm/system.h> 34 #include <asm/types.h> 35 36 #include <linux/nbd.h> 37 38 #define LO_MAGIC 0x68797548 39 40 #ifdef NDEBUG 41 #define dprintk(flags, fmt...) 42 #else /* NDEBUG */ 43 #define dprintk(flags, fmt...) do { \ 44 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \ 45 } while (0) 46 #define DBG_IOCTL 0x0004 47 #define DBG_INIT 0x0010 48 #define DBG_EXIT 0x0020 49 #define DBG_BLKDEV 0x0100 50 #define DBG_RX 0x0200 51 #define DBG_TX 0x0400 52 static unsigned int debugflags; 53 #endif /* NDEBUG */ 54 55 static unsigned int nbds_max = 16; 56 static struct nbd_device nbd_dev[MAX_NBD]; 57 58 /* 59 * Use just one lock (or at most 1 per NIC). Two arguments for this: 60 * 1. Each NIC is essentially a synchronization point for all servers 61 * accessed through that NIC so there's no need to have more locks 62 * than NICs anyway. 63 * 2. More locks lead to more "Dirty cache line bouncing" which will slow 64 * down each lock to the point where they're actually slower than just 65 * a single lock. 66 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! 67 */ 68 static DEFINE_SPINLOCK(nbd_lock); 69 70 #ifndef NDEBUG 71 static const char *ioctl_cmd_to_ascii(int cmd) 72 { 73 switch (cmd) { 74 case NBD_SET_SOCK: return "set-sock"; 75 case NBD_SET_BLKSIZE: return "set-blksize"; 76 case NBD_SET_SIZE: return "set-size"; 77 case NBD_DO_IT: return "do-it"; 78 case NBD_CLEAR_SOCK: return "clear-sock"; 79 case NBD_CLEAR_QUE: return "clear-que"; 80 case NBD_PRINT_DEBUG: return "print-debug"; 81 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; 82 case NBD_DISCONNECT: return "disconnect"; 83 case BLKROSET: return "set-read-only"; 84 case BLKFLSBUF: return "flush-buffer-cache"; 85 } 86 return "unknown"; 87 } 88 89 static const char *nbdcmd_to_ascii(int cmd) 90 { 91 switch (cmd) { 92 case NBD_CMD_READ: return "read"; 93 case NBD_CMD_WRITE: return "write"; 94 case NBD_CMD_DISC: return "disconnect"; 95 } 96 return "invalid"; 97 } 98 #endif /* NDEBUG */ 99 100 static void nbd_end_request(struct request *req) 101 { 102 int uptodate = (req->errors == 0) ? 1 : 0; 103 struct request_queue *q = req->q; 104 unsigned long flags; 105 106 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, 107 req, uptodate? "done": "failed"); 108 109 spin_lock_irqsave(q->queue_lock, flags); 110 if (!end_that_request_first(req, uptodate, req->nr_sectors)) { 111 end_that_request_last(req, uptodate); 112 } 113 spin_unlock_irqrestore(q->queue_lock, flags); 114 } 115 116 static void sock_shutdown(struct nbd_device *lo, int lock) 117 { 118 /* Forcibly shutdown the socket causing all listeners 119 * to error 120 * 121 * FIXME: This code is duplicated from sys_shutdown, but 122 * there should be a more generic interface rather than 123 * calling socket ops directly here */ 124 if (lock) 125 mutex_lock(&lo->tx_lock); 126 if (lo->sock) { 127 printk(KERN_WARNING "%s: shutting down socket\n", 128 lo->disk->disk_name); 129 lo->sock->ops->shutdown(lo->sock, SEND_SHUTDOWN|RCV_SHUTDOWN); 130 lo->sock = NULL; 131 } 132 if (lock) 133 mutex_unlock(&lo->tx_lock); 134 } 135 136 static void nbd_xmit_timeout(unsigned long arg) 137 { 138 struct task_struct *task = (struct task_struct *)arg; 139 140 printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", 141 task->comm, task->pid); 142 force_sig(SIGKILL, task); 143 } 144 145 /* 146 * Send or receive packet. 147 */ 148 static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size, 149 int msg_flags) 150 { 151 struct socket *sock = lo->sock; 152 int result; 153 struct msghdr msg; 154 struct kvec iov; 155 sigset_t blocked, oldset; 156 157 /* Allow interception of SIGKILL only 158 * Don't allow other signals to interrupt the transmission */ 159 siginitsetinv(&blocked, sigmask(SIGKILL)); 160 sigprocmask(SIG_SETMASK, &blocked, &oldset); 161 162 do { 163 sock->sk->sk_allocation = GFP_NOIO; 164 iov.iov_base = buf; 165 iov.iov_len = size; 166 msg.msg_name = NULL; 167 msg.msg_namelen = 0; 168 msg.msg_control = NULL; 169 msg.msg_controllen = 0; 170 msg.msg_flags = msg_flags | MSG_NOSIGNAL; 171 172 if (send) { 173 struct timer_list ti; 174 175 if (lo->xmit_timeout) { 176 init_timer(&ti); 177 ti.function = nbd_xmit_timeout; 178 ti.data = (unsigned long)current; 179 ti.expires = jiffies + lo->xmit_timeout; 180 add_timer(&ti); 181 } 182 result = kernel_sendmsg(sock, &msg, &iov, 1, size); 183 if (lo->xmit_timeout) 184 del_timer_sync(&ti); 185 } else 186 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0); 187 188 if (signal_pending(current)) { 189 siginfo_t info; 190 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", 191 task_pid_nr(current), current->comm, 192 dequeue_signal_lock(current, ¤t->blocked, &info)); 193 result = -EINTR; 194 sock_shutdown(lo, !send); 195 break; 196 } 197 198 if (result <= 0) { 199 if (result == 0) 200 result = -EPIPE; /* short read */ 201 break; 202 } 203 size -= result; 204 buf += result; 205 } while (size > 0); 206 207 sigprocmask(SIG_SETMASK, &oldset, NULL); 208 209 return result; 210 } 211 212 static inline int sock_send_bvec(struct nbd_device *lo, struct bio_vec *bvec, 213 int flags) 214 { 215 int result; 216 void *kaddr = kmap(bvec->bv_page); 217 result = sock_xmit(lo, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags); 218 kunmap(bvec->bv_page); 219 return result; 220 } 221 222 /* always call with the tx_lock held */ 223 static int nbd_send_req(struct nbd_device *lo, struct request *req) 224 { 225 int result, flags; 226 struct nbd_request request; 227 unsigned long size = req->nr_sectors << 9; 228 229 request.magic = htonl(NBD_REQUEST_MAGIC); 230 request.type = htonl(nbd_cmd(req)); 231 request.from = cpu_to_be64((u64) req->sector << 9); 232 request.len = htonl(size); 233 memcpy(request.handle, &req, sizeof(req)); 234 235 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n", 236 lo->disk->disk_name, req, 237 nbdcmd_to_ascii(nbd_cmd(req)), 238 (unsigned long long)req->sector << 9, 239 req->nr_sectors << 9); 240 result = sock_xmit(lo, 1, &request, sizeof(request), 241 (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); 242 if (result <= 0) { 243 printk(KERN_ERR "%s: Send control failed (result %d)\n", 244 lo->disk->disk_name, result); 245 goto error_out; 246 } 247 248 if (nbd_cmd(req) == NBD_CMD_WRITE) { 249 struct req_iterator iter; 250 struct bio_vec *bvec; 251 /* 252 * we are really probing at internals to determine 253 * whether to set MSG_MORE or not... 254 */ 255 rq_for_each_segment(bvec, req, iter) { 256 flags = 0; 257 if (!rq_iter_last(req, iter)) 258 flags = MSG_MORE; 259 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", 260 lo->disk->disk_name, req, bvec->bv_len); 261 result = sock_send_bvec(lo, bvec, flags); 262 if (result <= 0) { 263 printk(KERN_ERR "%s: Send data failed (result %d)\n", 264 lo->disk->disk_name, result); 265 goto error_out; 266 } 267 } 268 } 269 return 0; 270 271 error_out: 272 return 1; 273 } 274 275 static struct request *nbd_find_request(struct nbd_device *lo, 276 struct request *xreq) 277 { 278 struct request *req, *tmp; 279 int err; 280 281 err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq); 282 if (unlikely(err)) 283 goto out; 284 285 spin_lock(&lo->queue_lock); 286 list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) { 287 if (req != xreq) 288 continue; 289 list_del_init(&req->queuelist); 290 spin_unlock(&lo->queue_lock); 291 return req; 292 } 293 spin_unlock(&lo->queue_lock); 294 295 err = -ENOENT; 296 297 out: 298 return ERR_PTR(err); 299 } 300 301 static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec) 302 { 303 int result; 304 void *kaddr = kmap(bvec->bv_page); 305 result = sock_xmit(lo, 0, kaddr + bvec->bv_offset, bvec->bv_len, 306 MSG_WAITALL); 307 kunmap(bvec->bv_page); 308 return result; 309 } 310 311 /* NULL returned = something went wrong, inform userspace */ 312 static struct request *nbd_read_stat(struct nbd_device *lo) 313 { 314 int result; 315 struct nbd_reply reply; 316 struct request *req; 317 318 reply.magic = 0; 319 result = sock_xmit(lo, 0, &reply, sizeof(reply), MSG_WAITALL); 320 if (result <= 0) { 321 printk(KERN_ERR "%s: Receive control failed (result %d)\n", 322 lo->disk->disk_name, result); 323 goto harderror; 324 } 325 326 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { 327 printk(KERN_ERR "%s: Wrong magic (0x%lx)\n", 328 lo->disk->disk_name, 329 (unsigned long)ntohl(reply.magic)); 330 result = -EPROTO; 331 goto harderror; 332 } 333 334 req = nbd_find_request(lo, *(struct request **)reply.handle); 335 if (unlikely(IS_ERR(req))) { 336 result = PTR_ERR(req); 337 if (result != -ENOENT) 338 goto harderror; 339 340 printk(KERN_ERR "%s: Unexpected reply (%p)\n", 341 lo->disk->disk_name, reply.handle); 342 result = -EBADR; 343 goto harderror; 344 } 345 346 if (ntohl(reply.error)) { 347 printk(KERN_ERR "%s: Other side returned error (%d)\n", 348 lo->disk->disk_name, ntohl(reply.error)); 349 req->errors++; 350 return req; 351 } 352 353 dprintk(DBG_RX, "%s: request %p: got reply\n", 354 lo->disk->disk_name, req); 355 if (nbd_cmd(req) == NBD_CMD_READ) { 356 struct req_iterator iter; 357 struct bio_vec *bvec; 358 359 rq_for_each_segment(bvec, req, iter) { 360 result = sock_recv_bvec(lo, bvec); 361 if (result <= 0) { 362 printk(KERN_ERR "%s: Receive data failed (result %d)\n", 363 lo->disk->disk_name, result); 364 req->errors++; 365 return req; 366 } 367 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", 368 lo->disk->disk_name, req, bvec->bv_len); 369 } 370 } 371 return req; 372 harderror: 373 lo->harderror = result; 374 return NULL; 375 } 376 377 static ssize_t pid_show(struct gendisk *disk, char *page) 378 { 379 return sprintf(page, "%ld\n", 380 (long) ((struct nbd_device *)disk->private_data)->pid); 381 } 382 383 static struct disk_attribute pid_attr = { 384 .attr = { .name = "pid", .mode = S_IRUGO }, 385 .show = pid_show, 386 }; 387 388 static int nbd_do_it(struct nbd_device *lo) 389 { 390 struct request *req; 391 int ret; 392 393 BUG_ON(lo->magic != LO_MAGIC); 394 395 lo->pid = current->pid; 396 ret = sysfs_create_file(&lo->disk->kobj, &pid_attr.attr); 397 if (ret) { 398 printk(KERN_ERR "nbd: sysfs_create_file failed!"); 399 return ret; 400 } 401 402 while ((req = nbd_read_stat(lo)) != NULL) 403 nbd_end_request(req); 404 405 sysfs_remove_file(&lo->disk->kobj, &pid_attr.attr); 406 return 0; 407 } 408 409 static void nbd_clear_que(struct nbd_device *lo) 410 { 411 struct request *req; 412 413 BUG_ON(lo->magic != LO_MAGIC); 414 415 /* 416 * Because we have set lo->sock to NULL under the tx_lock, all 417 * modifications to the list must have completed by now. For 418 * the same reason, the active_req must be NULL. 419 * 420 * As a consequence, we don't need to take the spin lock while 421 * purging the list here. 422 */ 423 BUG_ON(lo->sock); 424 BUG_ON(lo->active_req); 425 426 while (!list_empty(&lo->queue_head)) { 427 req = list_entry(lo->queue_head.next, struct request, 428 queuelist); 429 list_del_init(&req->queuelist); 430 req->errors++; 431 nbd_end_request(req); 432 } 433 } 434 435 436 /* 437 * We always wait for result of write, for now. It would be nice to make it optional 438 * in future 439 * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK)) 440 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } 441 */ 442 443 static void do_nbd_request(struct request_queue * q) 444 { 445 struct request *req; 446 447 while ((req = elv_next_request(q)) != NULL) { 448 struct nbd_device *lo; 449 450 blkdev_dequeue_request(req); 451 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n", 452 req->rq_disk->disk_name, req, req->cmd_type); 453 454 if (!blk_fs_request(req)) 455 goto error_out; 456 457 lo = req->rq_disk->private_data; 458 459 BUG_ON(lo->magic != LO_MAGIC); 460 461 nbd_cmd(req) = NBD_CMD_READ; 462 if (rq_data_dir(req) == WRITE) { 463 nbd_cmd(req) = NBD_CMD_WRITE; 464 if (lo->flags & NBD_READ_ONLY) { 465 printk(KERN_ERR "%s: Write on read-only\n", 466 lo->disk->disk_name); 467 goto error_out; 468 } 469 } 470 471 req->errors = 0; 472 spin_unlock_irq(q->queue_lock); 473 474 mutex_lock(&lo->tx_lock); 475 if (unlikely(!lo->sock)) { 476 mutex_unlock(&lo->tx_lock); 477 printk(KERN_ERR "%s: Attempted send on closed socket\n", 478 lo->disk->disk_name); 479 req->errors++; 480 nbd_end_request(req); 481 spin_lock_irq(q->queue_lock); 482 continue; 483 } 484 485 lo->active_req = req; 486 487 if (nbd_send_req(lo, req) != 0) { 488 printk(KERN_ERR "%s: Request send failed\n", 489 lo->disk->disk_name); 490 req->errors++; 491 nbd_end_request(req); 492 } else { 493 spin_lock(&lo->queue_lock); 494 list_add(&req->queuelist, &lo->queue_head); 495 spin_unlock(&lo->queue_lock); 496 } 497 498 lo->active_req = NULL; 499 mutex_unlock(&lo->tx_lock); 500 wake_up_all(&lo->active_wq); 501 502 spin_lock_irq(q->queue_lock); 503 continue; 504 505 error_out: 506 req->errors++; 507 spin_unlock(q->queue_lock); 508 nbd_end_request(req); 509 spin_lock(q->queue_lock); 510 } 511 } 512 513 static int nbd_ioctl(struct inode *inode, struct file *file, 514 unsigned int cmd, unsigned long arg) 515 { 516 struct nbd_device *lo = inode->i_bdev->bd_disk->private_data; 517 int error; 518 struct request sreq ; 519 520 if (!capable(CAP_SYS_ADMIN)) 521 return -EPERM; 522 523 BUG_ON(lo->magic != LO_MAGIC); 524 525 /* Anyone capable of this syscall can do *real bad* things */ 526 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", 527 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); 528 529 switch (cmd) { 530 case NBD_DISCONNECT: 531 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); 532 sreq.cmd_type = REQ_TYPE_SPECIAL; 533 nbd_cmd(&sreq) = NBD_CMD_DISC; 534 /* 535 * Set these to sane values in case server implementation 536 * fails to check the request type first and also to keep 537 * debugging output cleaner. 538 */ 539 sreq.sector = 0; 540 sreq.nr_sectors = 0; 541 if (!lo->sock) 542 return -EINVAL; 543 mutex_lock(&lo->tx_lock); 544 nbd_send_req(lo, &sreq); 545 mutex_unlock(&lo->tx_lock); 546 return 0; 547 548 case NBD_CLEAR_SOCK: 549 error = 0; 550 mutex_lock(&lo->tx_lock); 551 lo->sock = NULL; 552 mutex_unlock(&lo->tx_lock); 553 file = lo->file; 554 lo->file = NULL; 555 nbd_clear_que(lo); 556 BUG_ON(!list_empty(&lo->queue_head)); 557 if (file) 558 fput(file); 559 return error; 560 case NBD_SET_SOCK: 561 if (lo->file) 562 return -EBUSY; 563 error = -EINVAL; 564 file = fget(arg); 565 if (file) { 566 inode = file->f_path.dentry->d_inode; 567 if (S_ISSOCK(inode->i_mode)) { 568 lo->file = file; 569 lo->sock = SOCKET_I(inode); 570 error = 0; 571 } else { 572 fput(file); 573 } 574 } 575 return error; 576 case NBD_SET_BLKSIZE: 577 lo->blksize = arg; 578 lo->bytesize &= ~(lo->blksize-1); 579 inode->i_bdev->bd_inode->i_size = lo->bytesize; 580 set_blocksize(inode->i_bdev, lo->blksize); 581 set_capacity(lo->disk, lo->bytesize >> 9); 582 return 0; 583 case NBD_SET_SIZE: 584 lo->bytesize = arg & ~(lo->blksize-1); 585 inode->i_bdev->bd_inode->i_size = lo->bytesize; 586 set_blocksize(inode->i_bdev, lo->blksize); 587 set_capacity(lo->disk, lo->bytesize >> 9); 588 return 0; 589 case NBD_SET_TIMEOUT: 590 lo->xmit_timeout = arg * HZ; 591 return 0; 592 case NBD_SET_SIZE_BLOCKS: 593 lo->bytesize = ((u64) arg) * lo->blksize; 594 inode->i_bdev->bd_inode->i_size = lo->bytesize; 595 set_blocksize(inode->i_bdev, lo->blksize); 596 set_capacity(lo->disk, lo->bytesize >> 9); 597 return 0; 598 case NBD_DO_IT: 599 if (!lo->file) 600 return -EINVAL; 601 error = nbd_do_it(lo); 602 if (error) 603 return error; 604 sock_shutdown(lo, 1); 605 file = lo->file; 606 lo->file = NULL; 607 nbd_clear_que(lo); 608 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name); 609 if (file) 610 fput(file); 611 lo->bytesize = 0; 612 inode->i_bdev->bd_inode->i_size = 0; 613 set_capacity(lo->disk, 0); 614 return lo->harderror; 615 case NBD_CLEAR_QUE: 616 /* 617 * This is for compatibility only. The queue is always cleared 618 * by NBD_DO_IT or NBD_CLEAR_SOCK. 619 */ 620 BUG_ON(!lo->sock && !list_empty(&lo->queue_head)); 621 return 0; 622 case NBD_PRINT_DEBUG: 623 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n", 624 inode->i_bdev->bd_disk->disk_name, 625 lo->queue_head.next, lo->queue_head.prev, 626 &lo->queue_head); 627 return 0; 628 } 629 return -EINVAL; 630 } 631 632 static struct block_device_operations nbd_fops = 633 { 634 .owner = THIS_MODULE, 635 .ioctl = nbd_ioctl, 636 }; 637 638 /* 639 * And here should be modules and kernel interface 640 * (Just smiley confuses emacs :-) 641 */ 642 643 static int __init nbd_init(void) 644 { 645 int err = -ENOMEM; 646 int i; 647 648 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 649 650 if (nbds_max > MAX_NBD) { 651 printk(KERN_CRIT "nbd: cannot allocate more than %u nbds; %u requested.\n", MAX_NBD, 652 nbds_max); 653 return -EINVAL; 654 } 655 656 for (i = 0; i < nbds_max; i++) { 657 struct gendisk *disk = alloc_disk(1); 658 if (!disk) 659 goto out; 660 nbd_dev[i].disk = disk; 661 /* 662 * The new linux 2.5 block layer implementation requires 663 * every gendisk to have its very own request_queue struct. 664 * These structs are big so we dynamically allocate them. 665 */ 666 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); 667 if (!disk->queue) { 668 put_disk(disk); 669 goto out; 670 } 671 } 672 673 if (register_blkdev(NBD_MAJOR, "nbd")) { 674 err = -EIO; 675 goto out; 676 } 677 678 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); 679 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); 680 681 for (i = 0; i < nbds_max; i++) { 682 struct gendisk *disk = nbd_dev[i].disk; 683 nbd_dev[i].file = NULL; 684 nbd_dev[i].magic = LO_MAGIC; 685 nbd_dev[i].flags = 0; 686 spin_lock_init(&nbd_dev[i].queue_lock); 687 INIT_LIST_HEAD(&nbd_dev[i].queue_head); 688 mutex_init(&nbd_dev[i].tx_lock); 689 init_waitqueue_head(&nbd_dev[i].active_wq); 690 nbd_dev[i].blksize = 1024; 691 nbd_dev[i].bytesize = 0; 692 disk->major = NBD_MAJOR; 693 disk->first_minor = i; 694 disk->fops = &nbd_fops; 695 disk->private_data = &nbd_dev[i]; 696 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO; 697 sprintf(disk->disk_name, "nbd%d", i); 698 set_capacity(disk, 0); 699 add_disk(disk); 700 } 701 702 return 0; 703 out: 704 while (i--) { 705 blk_cleanup_queue(nbd_dev[i].disk->queue); 706 put_disk(nbd_dev[i].disk); 707 } 708 return err; 709 } 710 711 static void __exit nbd_cleanup(void) 712 { 713 int i; 714 for (i = 0; i < nbds_max; i++) { 715 struct gendisk *disk = nbd_dev[i].disk; 716 nbd_dev[i].magic = 0; 717 if (disk) { 718 del_gendisk(disk); 719 blk_cleanup_queue(disk->queue); 720 put_disk(disk); 721 } 722 } 723 unregister_blkdev(NBD_MAJOR, "nbd"); 724 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); 725 } 726 727 module_init(nbd_init); 728 module_exit(nbd_cleanup); 729 730 MODULE_DESCRIPTION("Network Block Device"); 731 MODULE_LICENSE("GPL"); 732 733 module_param(nbds_max, int, 0444); 734 MODULE_PARM_DESC(nbds_max, "How many network block devices to initialize."); 735 #ifndef NDEBUG 736 module_param(debugflags, int, 0644); 737 MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); 738 #endif 739