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; 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 if (unlikely(!sock)) { 157 printk(KERN_ERR "%s: Attempted %s on closed socket in sock_xmit\n", 158 lo->disk->disk_name, (send ? "send" : "recv")); 159 return -EINVAL; 160 } 161 162 /* Allow interception of SIGKILL only 163 * Don't allow other signals to interrupt the transmission */ 164 siginitsetinv(&blocked, sigmask(SIGKILL)); 165 sigprocmask(SIG_SETMASK, &blocked, &oldset); 166 167 do { 168 sock->sk->sk_allocation = GFP_NOIO; 169 iov.iov_base = buf; 170 iov.iov_len = size; 171 msg.msg_name = NULL; 172 msg.msg_namelen = 0; 173 msg.msg_control = NULL; 174 msg.msg_controllen = 0; 175 msg.msg_flags = msg_flags | MSG_NOSIGNAL; 176 177 if (send) { 178 struct timer_list ti; 179 180 if (lo->xmit_timeout) { 181 init_timer(&ti); 182 ti.function = nbd_xmit_timeout; 183 ti.data = (unsigned long)current; 184 ti.expires = jiffies + lo->xmit_timeout; 185 add_timer(&ti); 186 } 187 result = kernel_sendmsg(sock, &msg, &iov, 1, size); 188 if (lo->xmit_timeout) 189 del_timer_sync(&ti); 190 } else 191 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0); 192 193 if (signal_pending(current)) { 194 siginfo_t info; 195 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", 196 task_pid_nr(current), current->comm, 197 dequeue_signal_lock(current, ¤t->blocked, &info)); 198 result = -EINTR; 199 sock_shutdown(lo, !send); 200 break; 201 } 202 203 if (result <= 0) { 204 if (result == 0) 205 result = -EPIPE; /* short read */ 206 break; 207 } 208 size -= result; 209 buf += result; 210 } while (size > 0); 211 212 sigprocmask(SIG_SETMASK, &oldset, NULL); 213 214 return result; 215 } 216 217 static inline int sock_send_bvec(struct nbd_device *lo, struct bio_vec *bvec, 218 int flags) 219 { 220 int result; 221 void *kaddr = kmap(bvec->bv_page); 222 result = sock_xmit(lo, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags); 223 kunmap(bvec->bv_page); 224 return result; 225 } 226 227 /* always call with the tx_lock held */ 228 static int nbd_send_req(struct nbd_device *lo, struct request *req) 229 { 230 int result, flags; 231 struct nbd_request request; 232 unsigned long size = req->nr_sectors << 9; 233 234 request.magic = htonl(NBD_REQUEST_MAGIC); 235 request.type = htonl(nbd_cmd(req)); 236 request.from = cpu_to_be64((u64) req->sector << 9); 237 request.len = htonl(size); 238 memcpy(request.handle, &req, sizeof(req)); 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(lo, 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 req_iterator iter; 255 struct bio_vec *bvec; 256 /* 257 * we are really probing at internals to determine 258 * whether to set MSG_MORE or not... 259 */ 260 rq_for_each_segment(bvec, req, iter) { 261 flags = 0; 262 if (!rq_iter_last(req, iter)) 263 flags = MSG_MORE; 264 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", 265 lo->disk->disk_name, req, bvec->bv_len); 266 result = sock_send_bvec(lo, bvec, flags); 267 if (result <= 0) { 268 printk(KERN_ERR "%s: Send data failed (result %d)\n", 269 lo->disk->disk_name, result); 270 goto error_out; 271 } 272 } 273 } 274 return 0; 275 276 error_out: 277 return 1; 278 } 279 280 static struct request *nbd_find_request(struct nbd_device *lo, 281 struct request *xreq) 282 { 283 struct request *req, *tmp; 284 int err; 285 286 err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq); 287 if (unlikely(err)) 288 goto out; 289 290 spin_lock(&lo->queue_lock); 291 list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) { 292 if (req != xreq) 293 continue; 294 list_del_init(&req->queuelist); 295 spin_unlock(&lo->queue_lock); 296 return req; 297 } 298 spin_unlock(&lo->queue_lock); 299 300 err = -ENOENT; 301 302 out: 303 return ERR_PTR(err); 304 } 305 306 static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec) 307 { 308 int result; 309 void *kaddr = kmap(bvec->bv_page); 310 result = sock_xmit(lo, 0, kaddr + bvec->bv_offset, bvec->bv_len, 311 MSG_WAITALL); 312 kunmap(bvec->bv_page); 313 return result; 314 } 315 316 /* NULL returned = something went wrong, inform userspace */ 317 static struct request *nbd_read_stat(struct nbd_device *lo) 318 { 319 int result; 320 struct nbd_reply reply; 321 struct request *req; 322 323 reply.magic = 0; 324 result = sock_xmit(lo, 0, &reply, sizeof(reply), MSG_WAITALL); 325 if (result <= 0) { 326 printk(KERN_ERR "%s: Receive control failed (result %d)\n", 327 lo->disk->disk_name, result); 328 goto harderror; 329 } 330 331 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { 332 printk(KERN_ERR "%s: Wrong magic (0x%lx)\n", 333 lo->disk->disk_name, 334 (unsigned long)ntohl(reply.magic)); 335 result = -EPROTO; 336 goto harderror; 337 } 338 339 req = nbd_find_request(lo, *(struct request **)reply.handle); 340 if (unlikely(IS_ERR(req))) { 341 result = PTR_ERR(req); 342 if (result != -ENOENT) 343 goto harderror; 344 345 printk(KERN_ERR "%s: Unexpected reply (%p)\n", 346 lo->disk->disk_name, reply.handle); 347 result = -EBADR; 348 goto harderror; 349 } 350 351 if (ntohl(reply.error)) { 352 printk(KERN_ERR "%s: Other side returned error (%d)\n", 353 lo->disk->disk_name, ntohl(reply.error)); 354 req->errors++; 355 return req; 356 } 357 358 dprintk(DBG_RX, "%s: request %p: got reply\n", 359 lo->disk->disk_name, req); 360 if (nbd_cmd(req) == NBD_CMD_READ) { 361 struct req_iterator iter; 362 struct bio_vec *bvec; 363 364 rq_for_each_segment(bvec, req, iter) { 365 result = sock_recv_bvec(lo, bvec); 366 if (result <= 0) { 367 printk(KERN_ERR "%s: Receive data failed (result %d)\n", 368 lo->disk->disk_name, result); 369 req->errors++; 370 return req; 371 } 372 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", 373 lo->disk->disk_name, req, bvec->bv_len); 374 } 375 } 376 return req; 377 harderror: 378 lo->harderror = result; 379 return NULL; 380 } 381 382 static ssize_t pid_show(struct device *dev, 383 struct device_attribute *attr, char *buf) 384 { 385 struct gendisk *disk = dev_to_disk(dev); 386 387 return sprintf(buf, "%ld\n", 388 (long) ((struct nbd_device *)disk->private_data)->pid); 389 } 390 391 static struct device_attribute pid_attr = { 392 .attr = { .name = "pid", .mode = S_IRUGO, .owner = THIS_MODULE }, 393 .show = pid_show, 394 }; 395 396 static int nbd_do_it(struct nbd_device *lo) 397 { 398 struct request *req; 399 int ret; 400 401 BUG_ON(lo->magic != LO_MAGIC); 402 403 lo->pid = current->pid; 404 ret = sysfs_create_file(&lo->disk->dev.kobj, &pid_attr.attr); 405 if (ret) { 406 printk(KERN_ERR "nbd: sysfs_create_file failed!"); 407 return ret; 408 } 409 410 while ((req = nbd_read_stat(lo)) != NULL) 411 nbd_end_request(req); 412 413 sysfs_remove_file(&lo->disk->dev.kobj, &pid_attr.attr); 414 return 0; 415 } 416 417 static void nbd_clear_que(struct nbd_device *lo) 418 { 419 struct request *req; 420 421 BUG_ON(lo->magic != LO_MAGIC); 422 423 /* 424 * Because we have set lo->sock to NULL under the tx_lock, all 425 * modifications to the list must have completed by now. For 426 * the same reason, the active_req must be NULL. 427 * 428 * As a consequence, we don't need to take the spin lock while 429 * purging the list here. 430 */ 431 BUG_ON(lo->sock); 432 BUG_ON(lo->active_req); 433 434 while (!list_empty(&lo->queue_head)) { 435 req = list_entry(lo->queue_head.next, struct request, 436 queuelist); 437 list_del_init(&req->queuelist); 438 req->errors++; 439 nbd_end_request(req); 440 } 441 } 442 443 444 /* 445 * We always wait for result of write, for now. It would be nice to make it optional 446 * in future 447 * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK)) 448 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } 449 */ 450 451 static void do_nbd_request(struct request_queue * q) 452 { 453 struct request *req; 454 455 while ((req = elv_next_request(q)) != NULL) { 456 struct nbd_device *lo; 457 458 blkdev_dequeue_request(req); 459 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n", 460 req->rq_disk->disk_name, req, req->cmd_type); 461 462 if (!blk_fs_request(req)) 463 goto error_out; 464 465 lo = req->rq_disk->private_data; 466 467 BUG_ON(lo->magic != LO_MAGIC); 468 469 nbd_cmd(req) = NBD_CMD_READ; 470 if (rq_data_dir(req) == WRITE) { 471 nbd_cmd(req) = NBD_CMD_WRITE; 472 if (lo->flags & NBD_READ_ONLY) { 473 printk(KERN_ERR "%s: Write on read-only\n", 474 lo->disk->disk_name); 475 goto error_out; 476 } 477 } 478 479 req->errors = 0; 480 spin_unlock_irq(q->queue_lock); 481 482 mutex_lock(&lo->tx_lock); 483 if (unlikely(!lo->sock)) { 484 mutex_unlock(&lo->tx_lock); 485 printk(KERN_ERR "%s: Attempted send on closed socket\n", 486 lo->disk->disk_name); 487 req->errors++; 488 nbd_end_request(req); 489 spin_lock_irq(q->queue_lock); 490 continue; 491 } 492 493 lo->active_req = req; 494 495 if (nbd_send_req(lo, req) != 0) { 496 printk(KERN_ERR "%s: Request send failed\n", 497 lo->disk->disk_name); 498 req->errors++; 499 nbd_end_request(req); 500 } else { 501 spin_lock(&lo->queue_lock); 502 list_add(&req->queuelist, &lo->queue_head); 503 spin_unlock(&lo->queue_lock); 504 } 505 506 lo->active_req = NULL; 507 mutex_unlock(&lo->tx_lock); 508 wake_up_all(&lo->active_wq); 509 510 spin_lock_irq(q->queue_lock); 511 continue; 512 513 error_out: 514 req->errors++; 515 spin_unlock(q->queue_lock); 516 nbd_end_request(req); 517 spin_lock(q->queue_lock); 518 } 519 } 520 521 static int nbd_ioctl(struct inode *inode, struct file *file, 522 unsigned int cmd, unsigned long arg) 523 { 524 struct nbd_device *lo = inode->i_bdev->bd_disk->private_data; 525 int error; 526 struct request sreq ; 527 528 if (!capable(CAP_SYS_ADMIN)) 529 return -EPERM; 530 531 BUG_ON(lo->magic != LO_MAGIC); 532 533 /* Anyone capable of this syscall can do *real bad* things */ 534 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", 535 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); 536 537 switch (cmd) { 538 case NBD_DISCONNECT: 539 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); 540 sreq.cmd_type = REQ_TYPE_SPECIAL; 541 nbd_cmd(&sreq) = NBD_CMD_DISC; 542 /* 543 * Set these to sane values in case server implementation 544 * fails to check the request type first and also to keep 545 * debugging output cleaner. 546 */ 547 sreq.sector = 0; 548 sreq.nr_sectors = 0; 549 if (!lo->sock) 550 return -EINVAL; 551 mutex_lock(&lo->tx_lock); 552 nbd_send_req(lo, &sreq); 553 mutex_unlock(&lo->tx_lock); 554 return 0; 555 556 case NBD_CLEAR_SOCK: 557 error = 0; 558 mutex_lock(&lo->tx_lock); 559 lo->sock = NULL; 560 mutex_unlock(&lo->tx_lock); 561 file = lo->file; 562 lo->file = NULL; 563 nbd_clear_que(lo); 564 BUG_ON(!list_empty(&lo->queue_head)); 565 if (file) 566 fput(file); 567 return error; 568 case NBD_SET_SOCK: 569 if (lo->file) 570 return -EBUSY; 571 error = -EINVAL; 572 file = fget(arg); 573 if (file) { 574 inode = file->f_path.dentry->d_inode; 575 if (S_ISSOCK(inode->i_mode)) { 576 lo->file = file; 577 lo->sock = SOCKET_I(inode); 578 error = 0; 579 } else { 580 fput(file); 581 } 582 } 583 return error; 584 case NBD_SET_BLKSIZE: 585 lo->blksize = arg; 586 lo->bytesize &= ~(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_SIZE: 592 lo->bytesize = arg & ~(lo->blksize-1); 593 inode->i_bdev->bd_inode->i_size = lo->bytesize; 594 set_blocksize(inode->i_bdev, lo->blksize); 595 set_capacity(lo->disk, lo->bytesize >> 9); 596 return 0; 597 case NBD_SET_TIMEOUT: 598 lo->xmit_timeout = arg * HZ; 599 return 0; 600 case NBD_SET_SIZE_BLOCKS: 601 lo->bytesize = ((u64) arg) * lo->blksize; 602 inode->i_bdev->bd_inode->i_size = lo->bytesize; 603 set_blocksize(inode->i_bdev, lo->blksize); 604 set_capacity(lo->disk, lo->bytesize >> 9); 605 return 0; 606 case NBD_DO_IT: 607 if (!lo->file) 608 return -EINVAL; 609 error = nbd_do_it(lo); 610 if (error) 611 return error; 612 sock_shutdown(lo, 1); 613 file = lo->file; 614 lo->file = NULL; 615 nbd_clear_que(lo); 616 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name); 617 if (file) 618 fput(file); 619 lo->bytesize = 0; 620 inode->i_bdev->bd_inode->i_size = 0; 621 set_capacity(lo->disk, 0); 622 return lo->harderror; 623 case NBD_CLEAR_QUE: 624 /* 625 * This is for compatibility only. The queue is always cleared 626 * by NBD_DO_IT or NBD_CLEAR_SOCK. 627 */ 628 BUG_ON(!lo->sock && !list_empty(&lo->queue_head)); 629 return 0; 630 case NBD_PRINT_DEBUG: 631 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n", 632 inode->i_bdev->bd_disk->disk_name, 633 lo->queue_head.next, lo->queue_head.prev, 634 &lo->queue_head); 635 return 0; 636 } 637 return -EINVAL; 638 } 639 640 static struct block_device_operations nbd_fops = 641 { 642 .owner = THIS_MODULE, 643 .ioctl = nbd_ioctl, 644 }; 645 646 /* 647 * And here should be modules and kernel interface 648 * (Just smiley confuses emacs :-) 649 */ 650 651 static int __init nbd_init(void) 652 { 653 int err = -ENOMEM; 654 int i; 655 656 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 657 658 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); 659 if (!nbd_dev) 660 return -ENOMEM; 661 662 for (i = 0; i < nbds_max; i++) { 663 struct gendisk *disk = alloc_disk(1); 664 elevator_t *old_e; 665 if (!disk) 666 goto out; 667 nbd_dev[i].disk = disk; 668 /* 669 * The new linux 2.5 block layer implementation requires 670 * every gendisk to have its very own request_queue struct. 671 * These structs are big so we dynamically allocate them. 672 */ 673 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); 674 if (!disk->queue) { 675 put_disk(disk); 676 goto out; 677 } 678 old_e = disk->queue->elevator; 679 if (elevator_init(disk->queue, "deadline") == 0 || 680 elevator_init(disk->queue, "noop") == 0) { 681 elevator_exit(old_e); 682 } 683 } 684 685 if (register_blkdev(NBD_MAJOR, "nbd")) { 686 err = -EIO; 687 goto out; 688 } 689 690 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); 691 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); 692 693 for (i = 0; i < nbds_max; i++) { 694 struct gendisk *disk = nbd_dev[i].disk; 695 nbd_dev[i].file = NULL; 696 nbd_dev[i].magic = LO_MAGIC; 697 nbd_dev[i].flags = 0; 698 spin_lock_init(&nbd_dev[i].queue_lock); 699 INIT_LIST_HEAD(&nbd_dev[i].queue_head); 700 mutex_init(&nbd_dev[i].tx_lock); 701 init_waitqueue_head(&nbd_dev[i].active_wq); 702 nbd_dev[i].blksize = 1024; 703 nbd_dev[i].bytesize = 0; 704 disk->major = NBD_MAJOR; 705 disk->first_minor = i; 706 disk->fops = &nbd_fops; 707 disk->private_data = &nbd_dev[i]; 708 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO; 709 sprintf(disk->disk_name, "nbd%d", i); 710 set_capacity(disk, 0); 711 add_disk(disk); 712 } 713 714 return 0; 715 out: 716 while (i--) { 717 blk_cleanup_queue(nbd_dev[i].disk->queue); 718 put_disk(nbd_dev[i].disk); 719 } 720 return err; 721 } 722 723 static void __exit nbd_cleanup(void) 724 { 725 int i; 726 for (i = 0; i < nbds_max; i++) { 727 struct gendisk *disk = nbd_dev[i].disk; 728 nbd_dev[i].magic = 0; 729 if (disk) { 730 del_gendisk(disk); 731 blk_cleanup_queue(disk->queue); 732 put_disk(disk); 733 } 734 } 735 unregister_blkdev(NBD_MAJOR, "nbd"); 736 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); 737 } 738 739 module_init(nbd_init); 740 module_exit(nbd_cleanup); 741 742 MODULE_DESCRIPTION("Network Block Device"); 743 MODULE_LICENSE("GPL"); 744 745 module_param(nbds_max, int, 0444); 746 MODULE_PARM_DESC(nbds_max, "How many network block devices to initialize."); 747 #ifndef NDEBUG 748 module_param(debugflags, int, 0644); 749 MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); 750 #endif 751