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 #include <linux/kthread.h> 33 34 #include <asm/uaccess.h> 35 #include <asm/system.h> 36 #include <asm/types.h> 37 38 #include <linux/nbd.h> 39 40 #define LO_MAGIC 0x68797548 41 42 #ifdef NDEBUG 43 #define dprintk(flags, fmt...) 44 #else /* NDEBUG */ 45 #define dprintk(flags, fmt...) do { \ 46 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \ 47 } while (0) 48 #define DBG_IOCTL 0x0004 49 #define DBG_INIT 0x0010 50 #define DBG_EXIT 0x0020 51 #define DBG_BLKDEV 0x0100 52 #define DBG_RX 0x0200 53 #define DBG_TX 0x0400 54 static unsigned int debugflags; 55 #endif /* NDEBUG */ 56 57 static unsigned int nbds_max = 16; 58 static struct nbd_device *nbd_dev; 59 static int max_part; 60 61 /* 62 * Use just one lock (or at most 1 per NIC). Two arguments for this: 63 * 1. Each NIC is essentially a synchronization point for all servers 64 * accessed through that NIC so there's no need to have more locks 65 * than NICs anyway. 66 * 2. More locks lead to more "Dirty cache line bouncing" which will slow 67 * down each lock to the point where they're actually slower than just 68 * a single lock. 69 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! 70 */ 71 static DEFINE_SPINLOCK(nbd_lock); 72 73 #ifndef NDEBUG 74 static const char *ioctl_cmd_to_ascii(int cmd) 75 { 76 switch (cmd) { 77 case NBD_SET_SOCK: return "set-sock"; 78 case NBD_SET_BLKSIZE: return "set-blksize"; 79 case NBD_SET_SIZE: return "set-size"; 80 case NBD_DO_IT: return "do-it"; 81 case NBD_CLEAR_SOCK: return "clear-sock"; 82 case NBD_CLEAR_QUE: return "clear-que"; 83 case NBD_PRINT_DEBUG: return "print-debug"; 84 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; 85 case NBD_DISCONNECT: return "disconnect"; 86 case BLKROSET: return "set-read-only"; 87 case BLKFLSBUF: return "flush-buffer-cache"; 88 } 89 return "unknown"; 90 } 91 92 static const char *nbdcmd_to_ascii(int cmd) 93 { 94 switch (cmd) { 95 case NBD_CMD_READ: return "read"; 96 case NBD_CMD_WRITE: return "write"; 97 case NBD_CMD_DISC: return "disconnect"; 98 } 99 return "invalid"; 100 } 101 #endif /* NDEBUG */ 102 103 static void nbd_end_request(struct request *req) 104 { 105 int error = req->errors ? -EIO : 0; 106 struct request_queue *q = req->q; 107 unsigned long flags; 108 109 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, 110 req, error ? "failed" : "done"); 111 112 spin_lock_irqsave(q->queue_lock, flags); 113 __blk_end_request(req, error, req->nr_sectors << 9); 114 spin_unlock_irqrestore(q->queue_lock, flags); 115 } 116 117 static void sock_shutdown(struct nbd_device *lo, int lock) 118 { 119 /* Forcibly shutdown the socket causing all listeners 120 * to error 121 * 122 * FIXME: This code is duplicated from sys_shutdown, but 123 * there should be a more generic interface rather than 124 * calling socket ops directly here */ 125 if (lock) 126 mutex_lock(&lo->tx_lock); 127 if (lo->sock) { 128 printk(KERN_WARNING "%s: shutting down socket\n", 129 lo->disk->disk_name); 130 kernel_sock_shutdown(lo->sock, SHUT_RDWR); 131 lo->sock = NULL; 132 } 133 if (lock) 134 mutex_unlock(&lo->tx_lock); 135 } 136 137 static void nbd_xmit_timeout(unsigned long arg) 138 { 139 struct task_struct *task = (struct task_struct *)arg; 140 141 printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", 142 task->comm, task->pid); 143 force_sig(SIGKILL, task); 144 } 145 146 /* 147 * Send or receive packet. 148 */ 149 static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size, 150 int msg_flags) 151 { 152 struct socket *sock = lo->sock; 153 int result; 154 struct msghdr msg; 155 struct kvec iov; 156 sigset_t blocked, oldset; 157 158 if (unlikely(!sock)) { 159 printk(KERN_ERR "%s: Attempted %s on closed socket in sock_xmit\n", 160 lo->disk->disk_name, (send ? "send" : "recv")); 161 return -EINVAL; 162 } 163 164 /* Allow interception of SIGKILL only 165 * Don't allow other signals to interrupt the transmission */ 166 siginitsetinv(&blocked, sigmask(SIGKILL)); 167 sigprocmask(SIG_SETMASK, &blocked, &oldset); 168 169 do { 170 sock->sk->sk_allocation = GFP_NOIO; 171 iov.iov_base = buf; 172 iov.iov_len = size; 173 msg.msg_name = NULL; 174 msg.msg_namelen = 0; 175 msg.msg_control = NULL; 176 msg.msg_controllen = 0; 177 msg.msg_flags = msg_flags | MSG_NOSIGNAL; 178 179 if (send) { 180 struct timer_list ti; 181 182 if (lo->xmit_timeout) { 183 init_timer(&ti); 184 ti.function = nbd_xmit_timeout; 185 ti.data = (unsigned long)current; 186 ti.expires = jiffies + lo->xmit_timeout; 187 add_timer(&ti); 188 } 189 result = kernel_sendmsg(sock, &msg, &iov, 1, size); 190 if (lo->xmit_timeout) 191 del_timer_sync(&ti); 192 } else 193 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0); 194 195 if (signal_pending(current)) { 196 siginfo_t info; 197 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", 198 task_pid_nr(current), current->comm, 199 dequeue_signal_lock(current, ¤t->blocked, &info)); 200 result = -EINTR; 201 sock_shutdown(lo, !send); 202 break; 203 } 204 205 if (result <= 0) { 206 if (result == 0) 207 result = -EPIPE; /* short read */ 208 break; 209 } 210 size -= result; 211 buf += result; 212 } while (size > 0); 213 214 sigprocmask(SIG_SETMASK, &oldset, NULL); 215 216 return result; 217 } 218 219 static inline int sock_send_bvec(struct nbd_device *lo, struct bio_vec *bvec, 220 int flags) 221 { 222 int result; 223 void *kaddr = kmap(bvec->bv_page); 224 result = sock_xmit(lo, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags); 225 kunmap(bvec->bv_page); 226 return result; 227 } 228 229 /* always call with the tx_lock held */ 230 static int nbd_send_req(struct nbd_device *lo, struct request *req) 231 { 232 int result, flags; 233 struct nbd_request request; 234 unsigned long size = req->nr_sectors << 9; 235 236 request.magic = htonl(NBD_REQUEST_MAGIC); 237 request.type = htonl(nbd_cmd(req)); 238 request.from = cpu_to_be64((u64) req->sector << 9); 239 request.len = htonl(size); 240 memcpy(request.handle, &req, sizeof(req)); 241 242 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n", 243 lo->disk->disk_name, req, 244 nbdcmd_to_ascii(nbd_cmd(req)), 245 (unsigned long long)req->sector << 9, 246 req->nr_sectors << 9); 247 result = sock_xmit(lo, 1, &request, sizeof(request), 248 (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); 249 if (result <= 0) { 250 printk(KERN_ERR "%s: Send control failed (result %d)\n", 251 lo->disk->disk_name, result); 252 goto error_out; 253 } 254 255 if (nbd_cmd(req) == NBD_CMD_WRITE) { 256 struct req_iterator iter; 257 struct bio_vec *bvec; 258 /* 259 * we are really probing at internals to determine 260 * whether to set MSG_MORE or not... 261 */ 262 rq_for_each_segment(bvec, req, iter) { 263 flags = 0; 264 if (!rq_iter_last(req, iter)) 265 flags = MSG_MORE; 266 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", 267 lo->disk->disk_name, req, bvec->bv_len); 268 result = sock_send_bvec(lo, bvec, flags); 269 if (result <= 0) { 270 printk(KERN_ERR "%s: Send data failed (result %d)\n", 271 lo->disk->disk_name, result); 272 goto error_out; 273 } 274 } 275 } 276 return 0; 277 278 error_out: 279 return 1; 280 } 281 282 static struct request *nbd_find_request(struct nbd_device *lo, 283 struct request *xreq) 284 { 285 struct request *req, *tmp; 286 int err; 287 288 err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq); 289 if (unlikely(err)) 290 goto out; 291 292 spin_lock(&lo->queue_lock); 293 list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) { 294 if (req != xreq) 295 continue; 296 list_del_init(&req->queuelist); 297 spin_unlock(&lo->queue_lock); 298 return req; 299 } 300 spin_unlock(&lo->queue_lock); 301 302 err = -ENOENT; 303 304 out: 305 return ERR_PTR(err); 306 } 307 308 static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec) 309 { 310 int result; 311 void *kaddr = kmap(bvec->bv_page); 312 result = sock_xmit(lo, 0, kaddr + bvec->bv_offset, bvec->bv_len, 313 MSG_WAITALL); 314 kunmap(bvec->bv_page); 315 return result; 316 } 317 318 /* NULL returned = something went wrong, inform userspace */ 319 static struct request *nbd_read_stat(struct nbd_device *lo) 320 { 321 int result; 322 struct nbd_reply reply; 323 struct request *req; 324 325 reply.magic = 0; 326 result = sock_xmit(lo, 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 } 332 333 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { 334 printk(KERN_ERR "%s: Wrong magic (0x%lx)\n", 335 lo->disk->disk_name, 336 (unsigned long)ntohl(reply.magic)); 337 result = -EPROTO; 338 goto harderror; 339 } 340 341 req = nbd_find_request(lo, *(struct request **)reply.handle); 342 if (IS_ERR(req)) { 343 result = PTR_ERR(req); 344 if (result != -ENOENT) 345 goto harderror; 346 347 printk(KERN_ERR "%s: Unexpected reply (%p)\n", 348 lo->disk->disk_name, reply.handle); 349 result = -EBADR; 350 goto harderror; 351 } 352 353 if (ntohl(reply.error)) { 354 printk(KERN_ERR "%s: Other side returned error (%d)\n", 355 lo->disk->disk_name, ntohl(reply.error)); 356 req->errors++; 357 return req; 358 } 359 360 dprintk(DBG_RX, "%s: request %p: got reply\n", 361 lo->disk->disk_name, req); 362 if (nbd_cmd(req) == NBD_CMD_READ) { 363 struct req_iterator iter; 364 struct bio_vec *bvec; 365 366 rq_for_each_segment(bvec, req, iter) { 367 result = sock_recv_bvec(lo, bvec); 368 if (result <= 0) { 369 printk(KERN_ERR "%s: Receive data failed (result %d)\n", 370 lo->disk->disk_name, result); 371 req->errors++; 372 return req; 373 } 374 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", 375 lo->disk->disk_name, req, bvec->bv_len); 376 } 377 } 378 return req; 379 harderror: 380 lo->harderror = result; 381 return NULL; 382 } 383 384 static ssize_t pid_show(struct device *dev, 385 struct device_attribute *attr, char *buf) 386 { 387 struct gendisk *disk = dev_to_disk(dev); 388 389 return sprintf(buf, "%ld\n", 390 (long) ((struct nbd_device *)disk->private_data)->pid); 391 } 392 393 static struct device_attribute pid_attr = { 394 .attr = { .name = "pid", .mode = S_IRUGO, .owner = THIS_MODULE }, 395 .show = pid_show, 396 }; 397 398 static int nbd_do_it(struct nbd_device *lo) 399 { 400 struct request *req; 401 int ret; 402 403 BUG_ON(lo->magic != LO_MAGIC); 404 405 lo->pid = current->pid; 406 ret = sysfs_create_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); 407 if (ret) { 408 printk(KERN_ERR "nbd: sysfs_create_file failed!"); 409 return ret; 410 } 411 412 while ((req = nbd_read_stat(lo)) != NULL) 413 nbd_end_request(req); 414 415 sysfs_remove_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); 416 return 0; 417 } 418 419 static void nbd_clear_que(struct nbd_device *lo) 420 { 421 struct request *req; 422 423 BUG_ON(lo->magic != LO_MAGIC); 424 425 /* 426 * Because we have set lo->sock to NULL under the tx_lock, all 427 * modifications to the list must have completed by now. For 428 * the same reason, the active_req must be NULL. 429 * 430 * As a consequence, we don't need to take the spin lock while 431 * purging the list here. 432 */ 433 BUG_ON(lo->sock); 434 BUG_ON(lo->active_req); 435 436 while (!list_empty(&lo->queue_head)) { 437 req = list_entry(lo->queue_head.next, struct request, 438 queuelist); 439 list_del_init(&req->queuelist); 440 req->errors++; 441 nbd_end_request(req); 442 } 443 } 444 445 446 static void nbd_handle_req(struct nbd_device *lo, struct request *req) 447 { 448 if (!blk_fs_request(req)) 449 goto error_out; 450 451 nbd_cmd(req) = NBD_CMD_READ; 452 if (rq_data_dir(req) == WRITE) { 453 nbd_cmd(req) = NBD_CMD_WRITE; 454 if (lo->flags & NBD_READ_ONLY) { 455 printk(KERN_ERR "%s: Write on read-only\n", 456 lo->disk->disk_name); 457 goto error_out; 458 } 459 } 460 461 req->errors = 0; 462 463 mutex_lock(&lo->tx_lock); 464 if (unlikely(!lo->sock)) { 465 mutex_unlock(&lo->tx_lock); 466 printk(KERN_ERR "%s: Attempted send on closed socket\n", 467 lo->disk->disk_name); 468 req->errors++; 469 nbd_end_request(req); 470 return; 471 } 472 473 lo->active_req = req; 474 475 if (nbd_send_req(lo, req) != 0) { 476 printk(KERN_ERR "%s: Request send failed\n", 477 lo->disk->disk_name); 478 req->errors++; 479 nbd_end_request(req); 480 } else { 481 spin_lock(&lo->queue_lock); 482 list_add(&req->queuelist, &lo->queue_head); 483 spin_unlock(&lo->queue_lock); 484 } 485 486 lo->active_req = NULL; 487 mutex_unlock(&lo->tx_lock); 488 wake_up_all(&lo->active_wq); 489 490 return; 491 492 error_out: 493 req->errors++; 494 nbd_end_request(req); 495 } 496 497 static int nbd_thread(void *data) 498 { 499 struct nbd_device *lo = data; 500 struct request *req; 501 502 set_user_nice(current, -20); 503 while (!kthread_should_stop() || !list_empty(&lo->waiting_queue)) { 504 /* wait for something to do */ 505 wait_event_interruptible(lo->waiting_wq, 506 kthread_should_stop() || 507 !list_empty(&lo->waiting_queue)); 508 509 /* extract request */ 510 if (list_empty(&lo->waiting_queue)) 511 continue; 512 513 spin_lock_irq(&lo->queue_lock); 514 req = list_entry(lo->waiting_queue.next, struct request, 515 queuelist); 516 list_del_init(&req->queuelist); 517 spin_unlock_irq(&lo->queue_lock); 518 519 /* handle request */ 520 nbd_handle_req(lo, req); 521 } 522 return 0; 523 } 524 525 /* 526 * We always wait for result of write, for now. It would be nice to make it optional 527 * in future 528 * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK)) 529 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } 530 */ 531 532 static void do_nbd_request(struct request_queue * q) 533 { 534 struct request *req; 535 536 while ((req = elv_next_request(q)) != NULL) { 537 struct nbd_device *lo; 538 539 blkdev_dequeue_request(req); 540 541 spin_unlock_irq(q->queue_lock); 542 543 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n", 544 req->rq_disk->disk_name, req, req->cmd_type); 545 546 lo = req->rq_disk->private_data; 547 548 BUG_ON(lo->magic != LO_MAGIC); 549 550 spin_lock_irq(&lo->queue_lock); 551 list_add_tail(&req->queuelist, &lo->waiting_queue); 552 spin_unlock_irq(&lo->queue_lock); 553 554 wake_up(&lo->waiting_wq); 555 556 spin_lock_irq(q->queue_lock); 557 } 558 } 559 560 static int nbd_ioctl(struct inode *inode, struct file *file, 561 unsigned int cmd, unsigned long arg) 562 { 563 struct nbd_device *lo = inode->i_bdev->bd_disk->private_data; 564 int error; 565 struct request sreq ; 566 struct task_struct *thread; 567 568 if (!capable(CAP_SYS_ADMIN)) 569 return -EPERM; 570 571 BUG_ON(lo->magic != LO_MAGIC); 572 573 /* Anyone capable of this syscall can do *real bad* things */ 574 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", 575 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); 576 577 switch (cmd) { 578 case NBD_DISCONNECT: 579 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); 580 blk_rq_init(NULL, &sreq); 581 sreq.cmd_type = REQ_TYPE_SPECIAL; 582 nbd_cmd(&sreq) = NBD_CMD_DISC; 583 /* 584 * Set these to sane values in case server implementation 585 * fails to check the request type first and also to keep 586 * debugging output cleaner. 587 */ 588 sreq.sector = 0; 589 sreq.nr_sectors = 0; 590 if (!lo->sock) 591 return -EINVAL; 592 mutex_lock(&lo->tx_lock); 593 nbd_send_req(lo, &sreq); 594 mutex_unlock(&lo->tx_lock); 595 return 0; 596 597 case NBD_CLEAR_SOCK: 598 error = 0; 599 mutex_lock(&lo->tx_lock); 600 lo->sock = NULL; 601 mutex_unlock(&lo->tx_lock); 602 file = lo->file; 603 lo->file = NULL; 604 nbd_clear_que(lo); 605 BUG_ON(!list_empty(&lo->queue_head)); 606 if (file) 607 fput(file); 608 return error; 609 case NBD_SET_SOCK: 610 if (lo->file) 611 return -EBUSY; 612 error = -EINVAL; 613 file = fget(arg); 614 if (file) { 615 struct block_device *bdev = inode->i_bdev; 616 inode = file->f_path.dentry->d_inode; 617 if (S_ISSOCK(inode->i_mode)) { 618 lo->file = file; 619 lo->sock = SOCKET_I(inode); 620 if (max_part > 0) 621 bdev->bd_invalidated = 1; 622 error = 0; 623 } else { 624 fput(file); 625 } 626 } 627 return error; 628 case NBD_SET_BLKSIZE: 629 lo->blksize = arg; 630 lo->bytesize &= ~(lo->blksize-1); 631 inode->i_bdev->bd_inode->i_size = lo->bytesize; 632 set_blocksize(inode->i_bdev, lo->blksize); 633 set_capacity(lo->disk, lo->bytesize >> 9); 634 return 0; 635 case NBD_SET_SIZE: 636 lo->bytesize = arg & ~(lo->blksize-1); 637 inode->i_bdev->bd_inode->i_size = lo->bytesize; 638 set_blocksize(inode->i_bdev, lo->blksize); 639 set_capacity(lo->disk, lo->bytesize >> 9); 640 return 0; 641 case NBD_SET_TIMEOUT: 642 lo->xmit_timeout = arg * HZ; 643 return 0; 644 case NBD_SET_SIZE_BLOCKS: 645 lo->bytesize = ((u64) arg) * lo->blksize; 646 inode->i_bdev->bd_inode->i_size = lo->bytesize; 647 set_blocksize(inode->i_bdev, lo->blksize); 648 set_capacity(lo->disk, lo->bytesize >> 9); 649 return 0; 650 case NBD_DO_IT: 651 if (!lo->file) 652 return -EINVAL; 653 thread = kthread_create(nbd_thread, lo, lo->disk->disk_name); 654 if (IS_ERR(thread)) 655 return PTR_ERR(thread); 656 wake_up_process(thread); 657 error = nbd_do_it(lo); 658 kthread_stop(thread); 659 if (error) 660 return error; 661 sock_shutdown(lo, 1); 662 file = lo->file; 663 lo->file = NULL; 664 nbd_clear_que(lo); 665 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name); 666 if (file) 667 fput(file); 668 lo->bytesize = 0; 669 inode->i_bdev->bd_inode->i_size = 0; 670 set_capacity(lo->disk, 0); 671 if (max_part > 0) 672 ioctl_by_bdev(inode->i_bdev, BLKRRPART, 0); 673 return lo->harderror; 674 case NBD_CLEAR_QUE: 675 /* 676 * This is for compatibility only. The queue is always cleared 677 * by NBD_DO_IT or NBD_CLEAR_SOCK. 678 */ 679 BUG_ON(!lo->sock && !list_empty(&lo->queue_head)); 680 return 0; 681 case NBD_PRINT_DEBUG: 682 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n", 683 inode->i_bdev->bd_disk->disk_name, 684 lo->queue_head.next, lo->queue_head.prev, 685 &lo->queue_head); 686 return 0; 687 } 688 return -EINVAL; 689 } 690 691 static struct block_device_operations nbd_fops = 692 { 693 .owner = THIS_MODULE, 694 .ioctl = nbd_ioctl, 695 }; 696 697 /* 698 * And here should be modules and kernel interface 699 * (Just smiley confuses emacs :-) 700 */ 701 702 static int __init nbd_init(void) 703 { 704 int err = -ENOMEM; 705 int i; 706 int part_shift; 707 708 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 709 710 if (max_part < 0) { 711 printk(KERN_CRIT "nbd: max_part must be >= 0\n"); 712 return -EINVAL; 713 } 714 715 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); 716 if (!nbd_dev) 717 return -ENOMEM; 718 719 part_shift = 0; 720 if (max_part > 0) 721 part_shift = fls(max_part); 722 723 for (i = 0; i < nbds_max; i++) { 724 struct gendisk *disk = alloc_disk(1 << part_shift); 725 elevator_t *old_e; 726 if (!disk) 727 goto out; 728 nbd_dev[i].disk = disk; 729 /* 730 * The new linux 2.5 block layer implementation requires 731 * every gendisk to have its very own request_queue struct. 732 * These structs are big so we dynamically allocate them. 733 */ 734 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); 735 if (!disk->queue) { 736 put_disk(disk); 737 goto out; 738 } 739 old_e = disk->queue->elevator; 740 if (elevator_init(disk->queue, "deadline") == 0 || 741 elevator_init(disk->queue, "noop") == 0) { 742 elevator_exit(old_e); 743 } 744 } 745 746 if (register_blkdev(NBD_MAJOR, "nbd")) { 747 err = -EIO; 748 goto out; 749 } 750 751 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); 752 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); 753 754 for (i = 0; i < nbds_max; i++) { 755 struct gendisk *disk = nbd_dev[i].disk; 756 nbd_dev[i].file = NULL; 757 nbd_dev[i].magic = LO_MAGIC; 758 nbd_dev[i].flags = 0; 759 INIT_LIST_HEAD(&nbd_dev[i].waiting_queue); 760 spin_lock_init(&nbd_dev[i].queue_lock); 761 INIT_LIST_HEAD(&nbd_dev[i].queue_head); 762 mutex_init(&nbd_dev[i].tx_lock); 763 init_waitqueue_head(&nbd_dev[i].active_wq); 764 init_waitqueue_head(&nbd_dev[i].waiting_wq); 765 nbd_dev[i].blksize = 1024; 766 nbd_dev[i].bytesize = 0; 767 disk->major = NBD_MAJOR; 768 disk->first_minor = i << part_shift; 769 disk->fops = &nbd_fops; 770 disk->private_data = &nbd_dev[i]; 771 sprintf(disk->disk_name, "nbd%d", i); 772 set_capacity(disk, 0); 773 add_disk(disk); 774 } 775 776 return 0; 777 out: 778 while (i--) { 779 blk_cleanup_queue(nbd_dev[i].disk->queue); 780 put_disk(nbd_dev[i].disk); 781 } 782 kfree(nbd_dev); 783 return err; 784 } 785 786 static void __exit nbd_cleanup(void) 787 { 788 int i; 789 for (i = 0; i < nbds_max; i++) { 790 struct gendisk *disk = nbd_dev[i].disk; 791 nbd_dev[i].magic = 0; 792 if (disk) { 793 del_gendisk(disk); 794 blk_cleanup_queue(disk->queue); 795 put_disk(disk); 796 } 797 } 798 unregister_blkdev(NBD_MAJOR, "nbd"); 799 kfree(nbd_dev); 800 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); 801 } 802 803 module_init(nbd_init); 804 module_exit(nbd_cleanup); 805 806 MODULE_DESCRIPTION("Network Block Device"); 807 MODULE_LICENSE("GPL"); 808 809 module_param(nbds_max, int, 0444); 810 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); 811 module_param(max_part, int, 0444); 812 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)"); 813 #ifndef NDEBUG 814 module_param(debugflags, int, 0644); 815 MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); 816 #endif 817