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}, 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 lo->pid = 0; 410 return ret; 411 } 412 413 while ((req = nbd_read_stat(lo)) != NULL) 414 nbd_end_request(req); 415 416 sysfs_remove_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); 417 lo->pid = 0; 418 return 0; 419 } 420 421 static void nbd_clear_que(struct nbd_device *lo) 422 { 423 struct request *req; 424 425 BUG_ON(lo->magic != LO_MAGIC); 426 427 /* 428 * Because we have set lo->sock to NULL under the tx_lock, all 429 * modifications to the list must have completed by now. For 430 * the same reason, the active_req must be NULL. 431 * 432 * As a consequence, we don't need to take the spin lock while 433 * purging the list here. 434 */ 435 BUG_ON(lo->sock); 436 BUG_ON(lo->active_req); 437 438 while (!list_empty(&lo->queue_head)) { 439 req = list_entry(lo->queue_head.next, struct request, 440 queuelist); 441 list_del_init(&req->queuelist); 442 req->errors++; 443 nbd_end_request(req); 444 } 445 } 446 447 448 static void nbd_handle_req(struct nbd_device *lo, struct request *req) 449 { 450 if (!blk_fs_request(req)) 451 goto error_out; 452 453 nbd_cmd(req) = NBD_CMD_READ; 454 if (rq_data_dir(req) == WRITE) { 455 nbd_cmd(req) = NBD_CMD_WRITE; 456 if (lo->flags & NBD_READ_ONLY) { 457 printk(KERN_ERR "%s: Write on read-only\n", 458 lo->disk->disk_name); 459 goto error_out; 460 } 461 } 462 463 req->errors = 0; 464 465 mutex_lock(&lo->tx_lock); 466 if (unlikely(!lo->sock)) { 467 mutex_unlock(&lo->tx_lock); 468 printk(KERN_ERR "%s: Attempted send on closed socket\n", 469 lo->disk->disk_name); 470 req->errors++; 471 nbd_end_request(req); 472 return; 473 } 474 475 lo->active_req = req; 476 477 if (nbd_send_req(lo, req) != 0) { 478 printk(KERN_ERR "%s: Request send failed\n", 479 lo->disk->disk_name); 480 req->errors++; 481 nbd_end_request(req); 482 } else { 483 spin_lock(&lo->queue_lock); 484 list_add(&req->queuelist, &lo->queue_head); 485 spin_unlock(&lo->queue_lock); 486 } 487 488 lo->active_req = NULL; 489 mutex_unlock(&lo->tx_lock); 490 wake_up_all(&lo->active_wq); 491 492 return; 493 494 error_out: 495 req->errors++; 496 nbd_end_request(req); 497 } 498 499 static int nbd_thread(void *data) 500 { 501 struct nbd_device *lo = data; 502 struct request *req; 503 504 set_user_nice(current, -20); 505 while (!kthread_should_stop() || !list_empty(&lo->waiting_queue)) { 506 /* wait for something to do */ 507 wait_event_interruptible(lo->waiting_wq, 508 kthread_should_stop() || 509 !list_empty(&lo->waiting_queue)); 510 511 /* extract request */ 512 if (list_empty(&lo->waiting_queue)) 513 continue; 514 515 spin_lock_irq(&lo->queue_lock); 516 req = list_entry(lo->waiting_queue.next, struct request, 517 queuelist); 518 list_del_init(&req->queuelist); 519 spin_unlock_irq(&lo->queue_lock); 520 521 /* handle request */ 522 nbd_handle_req(lo, req); 523 } 524 return 0; 525 } 526 527 /* 528 * We always wait for result of write, for now. It would be nice to make it optional 529 * in future 530 * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK)) 531 * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } 532 */ 533 534 static void do_nbd_request(struct request_queue * q) 535 { 536 struct request *req; 537 538 while ((req = elv_next_request(q)) != NULL) { 539 struct nbd_device *lo; 540 541 blkdev_dequeue_request(req); 542 543 spin_unlock_irq(q->queue_lock); 544 545 dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n", 546 req->rq_disk->disk_name, req, req->cmd_type); 547 548 lo = req->rq_disk->private_data; 549 550 BUG_ON(lo->magic != LO_MAGIC); 551 552 if (unlikely(!lo->sock)) { 553 printk(KERN_ERR "%s: Attempted send on closed socket\n", 554 lo->disk->disk_name); 555 req->errors++; 556 nbd_end_request(req); 557 spin_lock_irq(q->queue_lock); 558 continue; 559 } 560 561 spin_lock_irq(&lo->queue_lock); 562 list_add_tail(&req->queuelist, &lo->waiting_queue); 563 spin_unlock_irq(&lo->queue_lock); 564 565 wake_up(&lo->waiting_wq); 566 567 spin_lock_irq(q->queue_lock); 568 } 569 } 570 571 static int nbd_ioctl(struct block_device *bdev, fmode_t mode, 572 unsigned int cmd, unsigned long arg) 573 { 574 struct nbd_device *lo = bdev->bd_disk->private_data; 575 struct file *file; 576 int error; 577 struct request sreq ; 578 struct task_struct *thread; 579 580 if (!capable(CAP_SYS_ADMIN)) 581 return -EPERM; 582 583 BUG_ON(lo->magic != LO_MAGIC); 584 585 /* Anyone capable of this syscall can do *real bad* things */ 586 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", 587 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); 588 589 switch (cmd) { 590 case NBD_DISCONNECT: 591 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); 592 blk_rq_init(NULL, &sreq); 593 sreq.cmd_type = REQ_TYPE_SPECIAL; 594 nbd_cmd(&sreq) = NBD_CMD_DISC; 595 /* 596 * Set these to sane values in case server implementation 597 * fails to check the request type first and also to keep 598 * debugging output cleaner. 599 */ 600 sreq.sector = 0; 601 sreq.nr_sectors = 0; 602 if (!lo->sock) 603 return -EINVAL; 604 mutex_lock(&lo->tx_lock); 605 nbd_send_req(lo, &sreq); 606 mutex_unlock(&lo->tx_lock); 607 return 0; 608 609 case NBD_CLEAR_SOCK: 610 error = 0; 611 mutex_lock(&lo->tx_lock); 612 lo->sock = NULL; 613 mutex_unlock(&lo->tx_lock); 614 file = lo->file; 615 lo->file = NULL; 616 nbd_clear_que(lo); 617 BUG_ON(!list_empty(&lo->queue_head)); 618 if (file) 619 fput(file); 620 return error; 621 case NBD_SET_SOCK: 622 if (lo->file) 623 return -EBUSY; 624 error = -EINVAL; 625 file = fget(arg); 626 if (file) { 627 struct inode *inode = file->f_path.dentry->d_inode; 628 if (S_ISSOCK(inode->i_mode)) { 629 lo->file = file; 630 lo->sock = SOCKET_I(inode); 631 if (max_part > 0) 632 bdev->bd_invalidated = 1; 633 error = 0; 634 } else { 635 fput(file); 636 } 637 } 638 return error; 639 case NBD_SET_BLKSIZE: 640 lo->blksize = arg; 641 lo->bytesize &= ~(lo->blksize-1); 642 bdev->bd_inode->i_size = lo->bytesize; 643 set_blocksize(bdev, lo->blksize); 644 set_capacity(lo->disk, lo->bytesize >> 9); 645 return 0; 646 case NBD_SET_SIZE: 647 lo->bytesize = arg & ~(lo->blksize-1); 648 bdev->bd_inode->i_size = lo->bytesize; 649 set_blocksize(bdev, lo->blksize); 650 set_capacity(lo->disk, lo->bytesize >> 9); 651 return 0; 652 case NBD_SET_TIMEOUT: 653 lo->xmit_timeout = arg * HZ; 654 return 0; 655 case NBD_SET_SIZE_BLOCKS: 656 lo->bytesize = ((u64) arg) * lo->blksize; 657 bdev->bd_inode->i_size = lo->bytesize; 658 set_blocksize(bdev, lo->blksize); 659 set_capacity(lo->disk, lo->bytesize >> 9); 660 return 0; 661 case NBD_DO_IT: 662 if (lo->pid) 663 return -EBUSY; 664 if (!lo->file) 665 return -EINVAL; 666 thread = kthread_create(nbd_thread, lo, lo->disk->disk_name); 667 if (IS_ERR(thread)) 668 return PTR_ERR(thread); 669 wake_up_process(thread); 670 error = nbd_do_it(lo); 671 kthread_stop(thread); 672 if (error) 673 return error; 674 sock_shutdown(lo, 1); 675 file = lo->file; 676 lo->file = NULL; 677 nbd_clear_que(lo); 678 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name); 679 if (file) 680 fput(file); 681 lo->bytesize = 0; 682 bdev->bd_inode->i_size = 0; 683 set_capacity(lo->disk, 0); 684 if (max_part > 0) 685 ioctl_by_bdev(bdev, BLKRRPART, 0); 686 return lo->harderror; 687 case NBD_CLEAR_QUE: 688 /* 689 * This is for compatibility only. The queue is always cleared 690 * by NBD_DO_IT or NBD_CLEAR_SOCK. 691 */ 692 BUG_ON(!lo->sock && !list_empty(&lo->queue_head)); 693 return 0; 694 case NBD_PRINT_DEBUG: 695 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n", 696 bdev->bd_disk->disk_name, 697 lo->queue_head.next, lo->queue_head.prev, 698 &lo->queue_head); 699 return 0; 700 } 701 return -EINVAL; 702 } 703 704 static struct block_device_operations nbd_fops = 705 { 706 .owner = THIS_MODULE, 707 .locked_ioctl = nbd_ioctl, 708 }; 709 710 /* 711 * And here should be modules and kernel interface 712 * (Just smiley confuses emacs :-) 713 */ 714 715 static int __init nbd_init(void) 716 { 717 int err = -ENOMEM; 718 int i; 719 int part_shift; 720 721 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 722 723 if (max_part < 0) { 724 printk(KERN_CRIT "nbd: max_part must be >= 0\n"); 725 return -EINVAL; 726 } 727 728 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); 729 if (!nbd_dev) 730 return -ENOMEM; 731 732 part_shift = 0; 733 if (max_part > 0) 734 part_shift = fls(max_part); 735 736 for (i = 0; i < nbds_max; i++) { 737 struct gendisk *disk = alloc_disk(1 << part_shift); 738 if (!disk) 739 goto out; 740 nbd_dev[i].disk = disk; 741 /* 742 * The new linux 2.5 block layer implementation requires 743 * every gendisk to have its very own request_queue struct. 744 * These structs are big so we dynamically allocate them. 745 */ 746 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); 747 if (!disk->queue) { 748 put_disk(disk); 749 goto out; 750 } 751 /* 752 * Tell the block layer that we are not a rotational device 753 */ 754 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); 755 } 756 757 if (register_blkdev(NBD_MAJOR, "nbd")) { 758 err = -EIO; 759 goto out; 760 } 761 762 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); 763 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); 764 765 for (i = 0; i < nbds_max; i++) { 766 struct gendisk *disk = nbd_dev[i].disk; 767 nbd_dev[i].file = NULL; 768 nbd_dev[i].magic = LO_MAGIC; 769 nbd_dev[i].flags = 0; 770 INIT_LIST_HEAD(&nbd_dev[i].waiting_queue); 771 spin_lock_init(&nbd_dev[i].queue_lock); 772 INIT_LIST_HEAD(&nbd_dev[i].queue_head); 773 mutex_init(&nbd_dev[i].tx_lock); 774 init_waitqueue_head(&nbd_dev[i].active_wq); 775 init_waitqueue_head(&nbd_dev[i].waiting_wq); 776 nbd_dev[i].blksize = 1024; 777 nbd_dev[i].bytesize = 0; 778 disk->major = NBD_MAJOR; 779 disk->first_minor = i << part_shift; 780 disk->fops = &nbd_fops; 781 disk->private_data = &nbd_dev[i]; 782 sprintf(disk->disk_name, "nbd%d", i); 783 set_capacity(disk, 0); 784 add_disk(disk); 785 } 786 787 return 0; 788 out: 789 while (i--) { 790 blk_cleanup_queue(nbd_dev[i].disk->queue); 791 put_disk(nbd_dev[i].disk); 792 } 793 kfree(nbd_dev); 794 return err; 795 } 796 797 static void __exit nbd_cleanup(void) 798 { 799 int i; 800 for (i = 0; i < nbds_max; i++) { 801 struct gendisk *disk = nbd_dev[i].disk; 802 nbd_dev[i].magic = 0; 803 if (disk) { 804 del_gendisk(disk); 805 blk_cleanup_queue(disk->queue); 806 put_disk(disk); 807 } 808 } 809 unregister_blkdev(NBD_MAJOR, "nbd"); 810 kfree(nbd_dev); 811 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); 812 } 813 814 module_init(nbd_init); 815 module_exit(nbd_cleanup); 816 817 MODULE_DESCRIPTION("Network Block Device"); 818 MODULE_LICENSE("GPL"); 819 820 module_param(nbds_max, int, 0444); 821 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); 822 module_param(max_part, int, 0444); 823 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)"); 824 #ifndef NDEBUG 825 module_param(debugflags, int, 0644); 826 MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); 827 #endif 828