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 #include <linux/net.h> 32 33 #include <asm/uaccess.h> 34 #include <asm/system.h> 35 #include <asm/types.h> 36 37 #include <linux/nbd.h> 38 39 #define LO_MAGIC 0x68797548 40 41 #ifdef NDEBUG 42 #define dprintk(flags, fmt...) 43 #else /* NDEBUG */ 44 #define dprintk(flags, fmt...) do { \ 45 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \ 46 } while (0) 47 #define DBG_IOCTL 0x0004 48 #define DBG_INIT 0x0010 49 #define DBG_EXIT 0x0020 50 #define DBG_BLKDEV 0x0100 51 #define DBG_RX 0x0200 52 #define DBG_TX 0x0400 53 static unsigned int debugflags; 54 #endif /* NDEBUG */ 55 56 static unsigned int nbds_max = 16; 57 static struct nbd_device nbd_dev[MAX_NBD]; 58 59 /* 60 * Use just one lock (or at most 1 per NIC). Two arguments for this: 61 * 1. Each NIC is essentially a synchronization point for all servers 62 * accessed through that NIC so there's no need to have more locks 63 * than NICs anyway. 64 * 2. More locks lead to more "Dirty cache line bouncing" which will slow 65 * down each lock to the point where they're actually slower than just 66 * a single lock. 67 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! 68 */ 69 static DEFINE_SPINLOCK(nbd_lock); 70 71 #ifndef NDEBUG 72 static const char *ioctl_cmd_to_ascii(int cmd) 73 { 74 switch (cmd) { 75 case NBD_SET_SOCK: return "set-sock"; 76 case NBD_SET_BLKSIZE: return "set-blksize"; 77 case NBD_SET_SIZE: return "set-size"; 78 case NBD_DO_IT: return "do-it"; 79 case NBD_CLEAR_SOCK: return "clear-sock"; 80 case NBD_CLEAR_QUE: return "clear-que"; 81 case NBD_PRINT_DEBUG: return "print-debug"; 82 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; 83 case NBD_DISCONNECT: return "disconnect"; 84 case BLKROSET: return "set-read-only"; 85 case BLKFLSBUF: return "flush-buffer-cache"; 86 } 87 return "unknown"; 88 } 89 90 static const char *nbdcmd_to_ascii(int cmd) 91 { 92 switch (cmd) { 93 case NBD_CMD_READ: return "read"; 94 case NBD_CMD_WRITE: return "write"; 95 case NBD_CMD_DISC: return "disconnect"; 96 } 97 return "invalid"; 98 } 99 #endif /* NDEBUG */ 100 101 static void nbd_end_request(struct request *req) 102 { 103 int error = req->errors ? -EIO : 0; 104 struct request_queue *q = req->q; 105 unsigned long flags; 106 107 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, 108 req, error ? "failed" : "done"); 109 110 spin_lock_irqsave(q->queue_lock, flags); 111 __blk_end_request(req, error, req->nr_sectors << 9); 112 spin_unlock_irqrestore(q->queue_lock, flags); 113 } 114 115 static void sock_shutdown(struct nbd_device *lo, int lock) 116 { 117 /* Forcibly shutdown the socket causing all listeners 118 * to error 119 * 120 * FIXME: This code is duplicated from sys_shutdown, but 121 * there should be a more generic interface rather than 122 * calling socket ops directly here */ 123 if (lock) 124 mutex_lock(&lo->tx_lock); 125 if (lo->sock) { 126 printk(KERN_WARNING "%s: shutting down socket\n", 127 lo->disk->disk_name); 128 kernel_sock_shutdown(lo->sock, SHUT_RDWR); 129 lo->sock = NULL; 130 } 131 if (lock) 132 mutex_unlock(&lo->tx_lock); 133 } 134 135 static void nbd_xmit_timeout(unsigned long arg) 136 { 137 struct task_struct *task = (struct task_struct *)arg; 138 139 printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", 140 task->comm, task->pid); 141 force_sig(SIGKILL, task); 142 } 143 144 /* 145 * Send or receive packet. 146 */ 147 static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size, 148 int msg_flags) 149 { 150 struct socket *sock = lo->sock; 151 int result; 152 struct msghdr msg; 153 struct kvec iov; 154 sigset_t blocked, oldset; 155 156 /* Allow interception of SIGKILL only 157 * Don't allow other signals to interrupt the transmission */ 158 siginitsetinv(&blocked, sigmask(SIGKILL)); 159 sigprocmask(SIG_SETMASK, &blocked, &oldset); 160 161 do { 162 sock->sk->sk_allocation = GFP_NOIO; 163 iov.iov_base = buf; 164 iov.iov_len = size; 165 msg.msg_name = NULL; 166 msg.msg_namelen = 0; 167 msg.msg_control = NULL; 168 msg.msg_controllen = 0; 169 msg.msg_flags = msg_flags | MSG_NOSIGNAL; 170 171 if (send) { 172 struct timer_list ti; 173 174 if (lo->xmit_timeout) { 175 init_timer(&ti); 176 ti.function = nbd_xmit_timeout; 177 ti.data = (unsigned long)current; 178 ti.expires = jiffies + lo->xmit_timeout; 179 add_timer(&ti); 180 } 181 result = kernel_sendmsg(sock, &msg, &iov, 1, size); 182 if (lo->xmit_timeout) 183 del_timer_sync(&ti); 184 } else 185 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0); 186 187 if (signal_pending(current)) { 188 siginfo_t info; 189 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", 190 task_pid_nr(current), current->comm, 191 dequeue_signal_lock(current, ¤t->blocked, &info)); 192 result = -EINTR; 193 sock_shutdown(lo, !send); 194 break; 195 } 196 197 if (result <= 0) { 198 if (result == 0) 199 result = -EPIPE; /* short read */ 200 break; 201 } 202 size -= result; 203 buf += result; 204 } while (size > 0); 205 206 sigprocmask(SIG_SETMASK, &oldset, NULL); 207 208 return result; 209 } 210 211 static inline int sock_send_bvec(struct nbd_device *lo, struct bio_vec *bvec, 212 int flags) 213 { 214 int result; 215 void *kaddr = kmap(bvec->bv_page); 216 result = sock_xmit(lo, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags); 217 kunmap(bvec->bv_page); 218 return result; 219 } 220 221 /* always call with the tx_lock held */ 222 static int nbd_send_req(struct nbd_device *lo, struct request *req) 223 { 224 int result, flags; 225 struct nbd_request request; 226 unsigned long size = req->nr_sectors << 9; 227 228 request.magic = htonl(NBD_REQUEST_MAGIC); 229 request.type = htonl(nbd_cmd(req)); 230 request.from = cpu_to_be64((u64) req->sector << 9); 231 request.len = htonl(size); 232 memcpy(request.handle, &req, sizeof(req)); 233 234 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n", 235 lo->disk->disk_name, req, 236 nbdcmd_to_ascii(nbd_cmd(req)), 237 (unsigned long long)req->sector << 9, 238 req->nr_sectors << 9); 239 result = sock_xmit(lo, 1, &request, sizeof(request), 240 (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); 241 if (result <= 0) { 242 printk(KERN_ERR "%s: Send control failed (result %d)\n", 243 lo->disk->disk_name, result); 244 goto error_out; 245 } 246 247 if (nbd_cmd(req) == NBD_CMD_WRITE) { 248 struct req_iterator iter; 249 struct bio_vec *bvec; 250 /* 251 * we are really probing at internals to determine 252 * whether to set MSG_MORE or not... 253 */ 254 rq_for_each_segment(bvec, req, iter) { 255 flags = 0; 256 if (!rq_iter_last(req, iter)) 257 flags = MSG_MORE; 258 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", 259 lo->disk->disk_name, req, bvec->bv_len); 260 result = sock_send_bvec(lo, bvec, flags); 261 if (result <= 0) { 262 printk(KERN_ERR "%s: Send data failed (result %d)\n", 263 lo->disk->disk_name, result); 264 goto error_out; 265 } 266 } 267 } 268 return 0; 269 270 error_out: 271 return 1; 272 } 273 274 static struct request *nbd_find_request(struct nbd_device *lo, 275 struct request *xreq) 276 { 277 struct request *req, *tmp; 278 int err; 279 280 err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq); 281 if (unlikely(err)) 282 goto out; 283 284 spin_lock(&lo->queue_lock); 285 list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) { 286 if (req != xreq) 287 continue; 288 list_del_init(&req->queuelist); 289 spin_unlock(&lo->queue_lock); 290 return req; 291 } 292 spin_unlock(&lo->queue_lock); 293 294 err = -ENOENT; 295 296 out: 297 return ERR_PTR(err); 298 } 299 300 static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec) 301 { 302 int result; 303 void *kaddr = kmap(bvec->bv_page); 304 result = sock_xmit(lo, 0, kaddr + bvec->bv_offset, bvec->bv_len, 305 MSG_WAITALL); 306 kunmap(bvec->bv_page); 307 return result; 308 } 309 310 /* NULL returned = something went wrong, inform userspace */ 311 static struct request *nbd_read_stat(struct nbd_device *lo) 312 { 313 int result; 314 struct nbd_reply reply; 315 struct request *req; 316 317 reply.magic = 0; 318 result = sock_xmit(lo, 0, &reply, sizeof(reply), MSG_WAITALL); 319 if (result <= 0) { 320 printk(KERN_ERR "%s: Receive control failed (result %d)\n", 321 lo->disk->disk_name, result); 322 goto harderror; 323 } 324 325 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { 326 printk(KERN_ERR "%s: Wrong magic (0x%lx)\n", 327 lo->disk->disk_name, 328 (unsigned long)ntohl(reply.magic)); 329 result = -EPROTO; 330 goto harderror; 331 } 332 333 req = nbd_find_request(lo, *(struct request **)reply.handle); 334 if (unlikely(IS_ERR(req))) { 335 result = PTR_ERR(req); 336 if (result != -ENOENT) 337 goto harderror; 338 339 printk(KERN_ERR "%s: Unexpected reply (%p)\n", 340 lo->disk->disk_name, reply.handle); 341 result = -EBADR; 342 goto harderror; 343 } 344 345 if (ntohl(reply.error)) { 346 printk(KERN_ERR "%s: Other side returned error (%d)\n", 347 lo->disk->disk_name, ntohl(reply.error)); 348 req->errors++; 349 return req; 350 } 351 352 dprintk(DBG_RX, "%s: request %p: got reply\n", 353 lo->disk->disk_name, req); 354 if (nbd_cmd(req) == NBD_CMD_READ) { 355 struct req_iterator iter; 356 struct bio_vec *bvec; 357 358 rq_for_each_segment(bvec, req, iter) { 359 result = sock_recv_bvec(lo, bvec); 360 if (result <= 0) { 361 printk(KERN_ERR "%s: Receive data failed (result %d)\n", 362 lo->disk->disk_name, result); 363 req->errors++; 364 return req; 365 } 366 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", 367 lo->disk->disk_name, req, bvec->bv_len); 368 } 369 } 370 return req; 371 harderror: 372 lo->harderror = result; 373 return NULL; 374 } 375 376 static ssize_t pid_show(struct device *dev, 377 struct device_attribute *attr, char *buf) 378 { 379 struct gendisk *disk = dev_to_disk(dev); 380 381 return sprintf(buf, "%ld\n", 382 (long) ((struct nbd_device *)disk->private_data)->pid); 383 } 384 385 static struct device_attribute pid_attr = { 386 .attr = { .name = "pid", .mode = S_IRUGO, .owner = THIS_MODULE }, 387 .show = pid_show, 388 }; 389 390 static int nbd_do_it(struct nbd_device *lo) 391 { 392 struct request *req; 393 int ret; 394 395 BUG_ON(lo->magic != LO_MAGIC); 396 397 lo->pid = current->pid; 398 ret = sysfs_create_file(&lo->disk->dev.kobj, &pid_attr.attr); 399 if (ret) { 400 printk(KERN_ERR "nbd: sysfs_create_file failed!"); 401 return ret; 402 } 403 404 while ((req = nbd_read_stat(lo)) != NULL) 405 nbd_end_request(req); 406 407 sysfs_remove_file(&lo->disk->dev.kobj, &pid_attr.attr); 408 return 0; 409 } 410 411 static void nbd_clear_que(struct nbd_device *lo) 412 { 413 struct request *req; 414 415 BUG_ON(lo->magic != LO_MAGIC); 416 417 /* 418 * Because we have set lo->sock to NULL under the tx_lock, all 419 * modifications to the list must have completed by now. For 420 * the same reason, the active_req must be NULL. 421 * 422 * As a consequence, we don't need to take the spin lock while 423 * purging the list here. 424 */ 425 BUG_ON(lo->sock); 426 BUG_ON(lo->active_req); 427 428 while (!list_empty(&lo->queue_head)) { 429 req = list_entry(lo->queue_head.next, struct request, 430 queuelist); 431 list_del_init(&req->queuelist); 432 req->errors++; 433 nbd_end_request(req); 434 } 435 } 436 437 438 /* 439 * We always wait for result of write, for now. It would be nice to make it optional 440 * in future 441 * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK)) 442 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } 443 */ 444 445 static void do_nbd_request(struct request_queue * q) 446 { 447 struct request *req; 448 449 while ((req = elv_next_request(q)) != NULL) { 450 struct nbd_device *lo; 451 452 blkdev_dequeue_request(req); 453 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n", 454 req->rq_disk->disk_name, req, req->cmd_type); 455 456 if (!blk_fs_request(req)) 457 goto error_out; 458 459 lo = req->rq_disk->private_data; 460 461 BUG_ON(lo->magic != LO_MAGIC); 462 463 nbd_cmd(req) = NBD_CMD_READ; 464 if (rq_data_dir(req) == WRITE) { 465 nbd_cmd(req) = NBD_CMD_WRITE; 466 if (lo->flags & NBD_READ_ONLY) { 467 printk(KERN_ERR "%s: Write on read-only\n", 468 lo->disk->disk_name); 469 goto error_out; 470 } 471 } 472 473 req->errors = 0; 474 spin_unlock_irq(q->queue_lock); 475 476 mutex_lock(&lo->tx_lock); 477 if (unlikely(!lo->sock)) { 478 mutex_unlock(&lo->tx_lock); 479 printk(KERN_ERR "%s: Attempted send on closed socket\n", 480 lo->disk->disk_name); 481 req->errors++; 482 nbd_end_request(req); 483 spin_lock_irq(q->queue_lock); 484 continue; 485 } 486 487 lo->active_req = req; 488 489 if (nbd_send_req(lo, req) != 0) { 490 printk(KERN_ERR "%s: Request send failed\n", 491 lo->disk->disk_name); 492 req->errors++; 493 nbd_end_request(req); 494 } else { 495 spin_lock(&lo->queue_lock); 496 list_add(&req->queuelist, &lo->queue_head); 497 spin_unlock(&lo->queue_lock); 498 } 499 500 lo->active_req = NULL; 501 mutex_unlock(&lo->tx_lock); 502 wake_up_all(&lo->active_wq); 503 504 spin_lock_irq(q->queue_lock); 505 continue; 506 507 error_out: 508 req->errors++; 509 spin_unlock(q->queue_lock); 510 nbd_end_request(req); 511 spin_lock(q->queue_lock); 512 } 513 } 514 515 static int nbd_ioctl(struct inode *inode, struct file *file, 516 unsigned int cmd, unsigned long arg) 517 { 518 struct nbd_device *lo = inode->i_bdev->bd_disk->private_data; 519 int error; 520 struct request sreq ; 521 522 if (!capable(CAP_SYS_ADMIN)) 523 return -EPERM; 524 525 BUG_ON(lo->magic != LO_MAGIC); 526 527 /* Anyone capable of this syscall can do *real bad* things */ 528 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", 529 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); 530 531 switch (cmd) { 532 case NBD_DISCONNECT: 533 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); 534 sreq.cmd_type = REQ_TYPE_SPECIAL; 535 nbd_cmd(&sreq) = NBD_CMD_DISC; 536 /* 537 * Set these to sane values in case server implementation 538 * fails to check the request type first and also to keep 539 * debugging output cleaner. 540 */ 541 sreq.sector = 0; 542 sreq.nr_sectors = 0; 543 if (!lo->sock) 544 return -EINVAL; 545 mutex_lock(&lo->tx_lock); 546 nbd_send_req(lo, &sreq); 547 mutex_unlock(&lo->tx_lock); 548 return 0; 549 550 case NBD_CLEAR_SOCK: 551 error = 0; 552 mutex_lock(&lo->tx_lock); 553 lo->sock = NULL; 554 mutex_unlock(&lo->tx_lock); 555 file = lo->file; 556 lo->file = NULL; 557 nbd_clear_que(lo); 558 BUG_ON(!list_empty(&lo->queue_head)); 559 if (file) 560 fput(file); 561 return error; 562 case NBD_SET_SOCK: 563 if (lo->file) 564 return -EBUSY; 565 error = -EINVAL; 566 file = fget(arg); 567 if (file) { 568 inode = file->f_path.dentry->d_inode; 569 if (S_ISSOCK(inode->i_mode)) { 570 lo->file = file; 571 lo->sock = SOCKET_I(inode); 572 error = 0; 573 } else { 574 fput(file); 575 } 576 } 577 return error; 578 case NBD_SET_BLKSIZE: 579 lo->blksize = arg; 580 lo->bytesize &= ~(lo->blksize-1); 581 inode->i_bdev->bd_inode->i_size = lo->bytesize; 582 set_blocksize(inode->i_bdev, lo->blksize); 583 set_capacity(lo->disk, lo->bytesize >> 9); 584 return 0; 585 case NBD_SET_SIZE: 586 lo->bytesize = arg & ~(lo->blksize-1); 587 inode->i_bdev->bd_inode->i_size = lo->bytesize; 588 set_blocksize(inode->i_bdev, lo->blksize); 589 set_capacity(lo->disk, lo->bytesize >> 9); 590 return 0; 591 case NBD_SET_TIMEOUT: 592 lo->xmit_timeout = arg * HZ; 593 return 0; 594 case NBD_SET_SIZE_BLOCKS: 595 lo->bytesize = ((u64) arg) * lo->blksize; 596 inode->i_bdev->bd_inode->i_size = lo->bytesize; 597 set_blocksize(inode->i_bdev, lo->blksize); 598 set_capacity(lo->disk, lo->bytesize >> 9); 599 return 0; 600 case NBD_DO_IT: 601 if (!lo->file) 602 return -EINVAL; 603 error = nbd_do_it(lo); 604 if (error) 605 return error; 606 sock_shutdown(lo, 1); 607 file = lo->file; 608 lo->file = NULL; 609 nbd_clear_que(lo); 610 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name); 611 if (file) 612 fput(file); 613 lo->bytesize = 0; 614 inode->i_bdev->bd_inode->i_size = 0; 615 set_capacity(lo->disk, 0); 616 return lo->harderror; 617 case NBD_CLEAR_QUE: 618 /* 619 * This is for compatibility only. The queue is always cleared 620 * by NBD_DO_IT or NBD_CLEAR_SOCK. 621 */ 622 BUG_ON(!lo->sock && !list_empty(&lo->queue_head)); 623 return 0; 624 case NBD_PRINT_DEBUG: 625 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n", 626 inode->i_bdev->bd_disk->disk_name, 627 lo->queue_head.next, lo->queue_head.prev, 628 &lo->queue_head); 629 return 0; 630 } 631 return -EINVAL; 632 } 633 634 static struct block_device_operations nbd_fops = 635 { 636 .owner = THIS_MODULE, 637 .ioctl = nbd_ioctl, 638 }; 639 640 /* 641 * And here should be modules and kernel interface 642 * (Just smiley confuses emacs :-) 643 */ 644 645 static int __init nbd_init(void) 646 { 647 int err = -ENOMEM; 648 int i; 649 650 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 651 652 if (nbds_max > MAX_NBD) { 653 printk(KERN_CRIT "nbd: cannot allocate more than %u nbds; %u requested.\n", MAX_NBD, 654 nbds_max); 655 return -EINVAL; 656 } 657 658 for (i = 0; i < nbds_max; i++) { 659 struct gendisk *disk = alloc_disk(1); 660 if (!disk) 661 goto out; 662 nbd_dev[i].disk = disk; 663 /* 664 * The new linux 2.5 block layer implementation requires 665 * every gendisk to have its very own request_queue struct. 666 * These structs are big so we dynamically allocate them. 667 */ 668 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); 669 if (!disk->queue) { 670 put_disk(disk); 671 goto out; 672 } 673 } 674 675 if (register_blkdev(NBD_MAJOR, "nbd")) { 676 err = -EIO; 677 goto out; 678 } 679 680 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); 681 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); 682 683 for (i = 0; i < nbds_max; i++) { 684 struct gendisk *disk = nbd_dev[i].disk; 685 nbd_dev[i].file = NULL; 686 nbd_dev[i].magic = LO_MAGIC; 687 nbd_dev[i].flags = 0; 688 spin_lock_init(&nbd_dev[i].queue_lock); 689 INIT_LIST_HEAD(&nbd_dev[i].queue_head); 690 mutex_init(&nbd_dev[i].tx_lock); 691 init_waitqueue_head(&nbd_dev[i].active_wq); 692 nbd_dev[i].blksize = 1024; 693 nbd_dev[i].bytesize = 0; 694 disk->major = NBD_MAJOR; 695 disk->first_minor = i; 696 disk->fops = &nbd_fops; 697 disk->private_data = &nbd_dev[i]; 698 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO; 699 sprintf(disk->disk_name, "nbd%d", i); 700 set_capacity(disk, 0); 701 add_disk(disk); 702 } 703 704 return 0; 705 out: 706 while (i--) { 707 blk_cleanup_queue(nbd_dev[i].disk->queue); 708 put_disk(nbd_dev[i].disk); 709 } 710 return err; 711 } 712 713 static void __exit nbd_cleanup(void) 714 { 715 int i; 716 for (i = 0; i < nbds_max; i++) { 717 struct gendisk *disk = nbd_dev[i].disk; 718 nbd_dev[i].magic = 0; 719 if (disk) { 720 del_gendisk(disk); 721 blk_cleanup_queue(disk->queue); 722 put_disk(disk); 723 } 724 } 725 unregister_blkdev(NBD_MAJOR, "nbd"); 726 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); 727 } 728 729 module_init(nbd_init); 730 module_exit(nbd_cleanup); 731 732 MODULE_DESCRIPTION("Network Block Device"); 733 MODULE_LICENSE("GPL"); 734 735 module_param(nbds_max, int, 0444); 736 MODULE_PARM_DESC(nbds_max, "How many network block devices to initialize."); 737 #ifndef NDEBUG 738 module_param(debugflags, int, 0644); 739 MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); 740 #endif 741