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, 2008 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/mutex.h> 28 #include <linux/compiler.h> 29 #include <linux/err.h> 30 #include <linux/kernel.h> 31 #include <linux/slab.h> 32 #include <net/sock.h> 33 #include <linux/net.h> 34 #include <linux/kthread.h> 35 36 #include <asm/uaccess.h> 37 #include <asm/system.h> 38 #include <asm/types.h> 39 40 #include <linux/nbd.h> 41 42 #define LO_MAGIC 0x68797548 43 44 #ifdef NDEBUG 45 #define dprintk(flags, fmt...) 46 #else /* NDEBUG */ 47 #define dprintk(flags, fmt...) do { \ 48 if (debugflags & (flags)) printk(KERN_DEBUG fmt); \ 49 } while (0) 50 #define DBG_IOCTL 0x0004 51 #define DBG_INIT 0x0010 52 #define DBG_EXIT 0x0020 53 #define DBG_BLKDEV 0x0100 54 #define DBG_RX 0x0200 55 #define DBG_TX 0x0400 56 static unsigned int debugflags; 57 #endif /* NDEBUG */ 58 59 static unsigned int nbds_max = 16; 60 static struct nbd_device *nbd_dev; 61 static int max_part; 62 63 /* 64 * Use just one lock (or at most 1 per NIC). Two arguments for this: 65 * 1. Each NIC is essentially a synchronization point for all servers 66 * accessed through that NIC so there's no need to have more locks 67 * than NICs anyway. 68 * 2. More locks lead to more "Dirty cache line bouncing" which will slow 69 * down each lock to the point where they're actually slower than just 70 * a single lock. 71 * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! 72 */ 73 static DEFINE_SPINLOCK(nbd_lock); 74 75 #ifndef NDEBUG 76 static const char *ioctl_cmd_to_ascii(int cmd) 77 { 78 switch (cmd) { 79 case NBD_SET_SOCK: return "set-sock"; 80 case NBD_SET_BLKSIZE: return "set-blksize"; 81 case NBD_SET_SIZE: return "set-size"; 82 case NBD_DO_IT: return "do-it"; 83 case NBD_CLEAR_SOCK: return "clear-sock"; 84 case NBD_CLEAR_QUE: return "clear-que"; 85 case NBD_PRINT_DEBUG: return "print-debug"; 86 case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; 87 case NBD_DISCONNECT: return "disconnect"; 88 case BLKROSET: return "set-read-only"; 89 case BLKFLSBUF: return "flush-buffer-cache"; 90 } 91 return "unknown"; 92 } 93 94 static const char *nbdcmd_to_ascii(int cmd) 95 { 96 switch (cmd) { 97 case NBD_CMD_READ: return "read"; 98 case NBD_CMD_WRITE: return "write"; 99 case NBD_CMD_DISC: return "disconnect"; 100 } 101 return "invalid"; 102 } 103 #endif /* NDEBUG */ 104 105 static void nbd_end_request(struct request *req) 106 { 107 int error = req->errors ? -EIO : 0; 108 struct request_queue *q = req->q; 109 unsigned long flags; 110 111 dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, 112 req, error ? "failed" : "done"); 113 114 spin_lock_irqsave(q->queue_lock, flags); 115 __blk_end_request_all(req, error); 116 spin_unlock_irqrestore(q->queue_lock, flags); 117 } 118 119 static void sock_shutdown(struct nbd_device *lo, int lock) 120 { 121 /* Forcibly shutdown the socket causing all listeners 122 * to error 123 * 124 * FIXME: This code is duplicated from sys_shutdown, but 125 * there should be a more generic interface rather than 126 * calling socket ops directly here */ 127 if (lock) 128 mutex_lock(&lo->tx_lock); 129 if (lo->sock) { 130 printk(KERN_WARNING "%s: shutting down socket\n", 131 lo->disk->disk_name); 132 kernel_sock_shutdown(lo->sock, SHUT_RDWR); 133 lo->sock = NULL; 134 } 135 if (lock) 136 mutex_unlock(&lo->tx_lock); 137 } 138 139 static void nbd_xmit_timeout(unsigned long arg) 140 { 141 struct task_struct *task = (struct task_struct *)arg; 142 143 printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", 144 task->comm, task->pid); 145 force_sig(SIGKILL, task); 146 } 147 148 /* 149 * Send or receive packet. 150 */ 151 static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size, 152 int msg_flags) 153 { 154 struct socket *sock = lo->sock; 155 int result; 156 struct msghdr msg; 157 struct kvec iov; 158 sigset_t blocked, oldset; 159 160 if (unlikely(!sock)) { 161 printk(KERN_ERR "%s: Attempted %s on closed socket in sock_xmit\n", 162 lo->disk->disk_name, (send ? "send" : "recv")); 163 return -EINVAL; 164 } 165 166 /* Allow interception of SIGKILL only 167 * Don't allow other signals to interrupt the transmission */ 168 siginitsetinv(&blocked, sigmask(SIGKILL)); 169 sigprocmask(SIG_SETMASK, &blocked, &oldset); 170 171 do { 172 sock->sk->sk_allocation = GFP_NOIO; 173 iov.iov_base = buf; 174 iov.iov_len = size; 175 msg.msg_name = NULL; 176 msg.msg_namelen = 0; 177 msg.msg_control = NULL; 178 msg.msg_controllen = 0; 179 msg.msg_flags = msg_flags | MSG_NOSIGNAL; 180 181 if (send) { 182 struct timer_list ti; 183 184 if (lo->xmit_timeout) { 185 init_timer(&ti); 186 ti.function = nbd_xmit_timeout; 187 ti.data = (unsigned long)current; 188 ti.expires = jiffies + lo->xmit_timeout; 189 add_timer(&ti); 190 } 191 result = kernel_sendmsg(sock, &msg, &iov, 1, size); 192 if (lo->xmit_timeout) 193 del_timer_sync(&ti); 194 } else 195 result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0); 196 197 if (signal_pending(current)) { 198 siginfo_t info; 199 printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", 200 task_pid_nr(current), current->comm, 201 dequeue_signal_lock(current, ¤t->blocked, &info)); 202 result = -EINTR; 203 sock_shutdown(lo, !send); 204 break; 205 } 206 207 if (result <= 0) { 208 if (result == 0) 209 result = -EPIPE; /* short read */ 210 break; 211 } 212 size -= result; 213 buf += result; 214 } while (size > 0); 215 216 sigprocmask(SIG_SETMASK, &oldset, NULL); 217 218 return result; 219 } 220 221 static inline int sock_send_bvec(struct nbd_device *lo, struct bio_vec *bvec, 222 int flags) 223 { 224 int result; 225 void *kaddr = kmap(bvec->bv_page); 226 result = sock_xmit(lo, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags); 227 kunmap(bvec->bv_page); 228 return result; 229 } 230 231 /* always call with the tx_lock held */ 232 static int nbd_send_req(struct nbd_device *lo, struct request *req) 233 { 234 int result, flags; 235 struct nbd_request request; 236 unsigned long size = blk_rq_bytes(req); 237 238 request.magic = htonl(NBD_REQUEST_MAGIC); 239 request.type = htonl(nbd_cmd(req)); 240 request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); 241 request.len = htonl(size); 242 memcpy(request.handle, &req, sizeof(req)); 243 244 dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n", 245 lo->disk->disk_name, req, 246 nbdcmd_to_ascii(nbd_cmd(req)), 247 (unsigned long long)blk_rq_pos(req) << 9, 248 blk_rq_bytes(req)); 249 result = sock_xmit(lo, 1, &request, sizeof(request), 250 (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); 251 if (result <= 0) { 252 printk(KERN_ERR "%s: Send control failed (result %d)\n", 253 lo->disk->disk_name, result); 254 goto error_out; 255 } 256 257 if (nbd_cmd(req) == NBD_CMD_WRITE) { 258 struct req_iterator iter; 259 struct bio_vec *bvec; 260 /* 261 * we are really probing at internals to determine 262 * whether to set MSG_MORE or not... 263 */ 264 rq_for_each_segment(bvec, req, iter) { 265 flags = 0; 266 if (!rq_iter_last(req, iter)) 267 flags = MSG_MORE; 268 dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", 269 lo->disk->disk_name, req, bvec->bv_len); 270 result = sock_send_bvec(lo, bvec, flags); 271 if (result <= 0) { 272 printk(KERN_ERR "%s: Send data failed (result %d)\n", 273 lo->disk->disk_name, result); 274 goto error_out; 275 } 276 } 277 } 278 return 0; 279 280 error_out: 281 return -EIO; 282 } 283 284 static struct request *nbd_find_request(struct nbd_device *lo, 285 struct request *xreq) 286 { 287 struct request *req, *tmp; 288 int err; 289 290 err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq); 291 if (unlikely(err)) 292 goto out; 293 294 spin_lock(&lo->queue_lock); 295 list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) { 296 if (req != xreq) 297 continue; 298 list_del_init(&req->queuelist); 299 spin_unlock(&lo->queue_lock); 300 return req; 301 } 302 spin_unlock(&lo->queue_lock); 303 304 err = -ENOENT; 305 306 out: 307 return ERR_PTR(err); 308 } 309 310 static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec) 311 { 312 int result; 313 void *kaddr = kmap(bvec->bv_page); 314 result = sock_xmit(lo, 0, kaddr + bvec->bv_offset, bvec->bv_len, 315 MSG_WAITALL); 316 kunmap(bvec->bv_page); 317 return result; 318 } 319 320 /* NULL returned = something went wrong, inform userspace */ 321 static struct request *nbd_read_stat(struct nbd_device *lo) 322 { 323 int result; 324 struct nbd_reply reply; 325 struct request *req; 326 327 reply.magic = 0; 328 result = sock_xmit(lo, 0, &reply, sizeof(reply), MSG_WAITALL); 329 if (result <= 0) { 330 printk(KERN_ERR "%s: Receive control failed (result %d)\n", 331 lo->disk->disk_name, result); 332 goto harderror; 333 } 334 335 if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { 336 printk(KERN_ERR "%s: Wrong magic (0x%lx)\n", 337 lo->disk->disk_name, 338 (unsigned long)ntohl(reply.magic)); 339 result = -EPROTO; 340 goto harderror; 341 } 342 343 req = nbd_find_request(lo, *(struct request **)reply.handle); 344 if (IS_ERR(req)) { 345 result = PTR_ERR(req); 346 if (result != -ENOENT) 347 goto harderror; 348 349 printk(KERN_ERR "%s: Unexpected reply (%p)\n", 350 lo->disk->disk_name, reply.handle); 351 result = -EBADR; 352 goto harderror; 353 } 354 355 if (ntohl(reply.error)) { 356 printk(KERN_ERR "%s: Other side returned error (%d)\n", 357 lo->disk->disk_name, ntohl(reply.error)); 358 req->errors++; 359 return req; 360 } 361 362 dprintk(DBG_RX, "%s: request %p: got reply\n", 363 lo->disk->disk_name, req); 364 if (nbd_cmd(req) == NBD_CMD_READ) { 365 struct req_iterator iter; 366 struct bio_vec *bvec; 367 368 rq_for_each_segment(bvec, req, iter) { 369 result = sock_recv_bvec(lo, bvec); 370 if (result <= 0) { 371 printk(KERN_ERR "%s: Receive data failed (result %d)\n", 372 lo->disk->disk_name, result); 373 req->errors++; 374 return req; 375 } 376 dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", 377 lo->disk->disk_name, req, bvec->bv_len); 378 } 379 } 380 return req; 381 harderror: 382 lo->harderror = result; 383 return NULL; 384 } 385 386 static ssize_t pid_show(struct device *dev, 387 struct device_attribute *attr, char *buf) 388 { 389 struct gendisk *disk = dev_to_disk(dev); 390 391 return sprintf(buf, "%ld\n", 392 (long) ((struct nbd_device *)disk->private_data)->pid); 393 } 394 395 static struct device_attribute pid_attr = { 396 .attr = { .name = "pid", .mode = S_IRUGO}, 397 .show = pid_show, 398 }; 399 400 static int nbd_do_it(struct nbd_device *lo) 401 { 402 struct request *req; 403 int ret; 404 405 BUG_ON(lo->magic != LO_MAGIC); 406 407 lo->pid = current->pid; 408 ret = sysfs_create_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); 409 if (ret) { 410 printk(KERN_ERR "nbd: sysfs_create_file failed!"); 411 lo->pid = 0; 412 return ret; 413 } 414 415 while ((req = nbd_read_stat(lo)) != NULL) 416 nbd_end_request(req); 417 418 sysfs_remove_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); 419 lo->pid = 0; 420 return 0; 421 } 422 423 static void nbd_clear_que(struct nbd_device *lo) 424 { 425 struct request *req; 426 427 BUG_ON(lo->magic != LO_MAGIC); 428 429 /* 430 * Because we have set lo->sock to NULL under the tx_lock, all 431 * modifications to the list must have completed by now. For 432 * the same reason, the active_req must be NULL. 433 * 434 * As a consequence, we don't need to take the spin lock while 435 * purging the list here. 436 */ 437 BUG_ON(lo->sock); 438 BUG_ON(lo->active_req); 439 440 while (!list_empty(&lo->queue_head)) { 441 req = list_entry(lo->queue_head.next, struct request, 442 queuelist); 443 list_del_init(&req->queuelist); 444 req->errors++; 445 nbd_end_request(req); 446 } 447 } 448 449 450 static void nbd_handle_req(struct nbd_device *lo, struct request *req) 451 { 452 if (req->cmd_type != REQ_TYPE_FS) 453 goto error_out; 454 455 nbd_cmd(req) = NBD_CMD_READ; 456 if (rq_data_dir(req) == WRITE) { 457 nbd_cmd(req) = NBD_CMD_WRITE; 458 if (lo->flags & NBD_READ_ONLY) { 459 printk(KERN_ERR "%s: Write on read-only\n", 460 lo->disk->disk_name); 461 goto error_out; 462 } 463 } 464 465 req->errors = 0; 466 467 mutex_lock(&lo->tx_lock); 468 if (unlikely(!lo->sock)) { 469 mutex_unlock(&lo->tx_lock); 470 printk(KERN_ERR "%s: Attempted send on closed socket\n", 471 lo->disk->disk_name); 472 goto error_out; 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 = blk_fetch_request(q)) != NULL) { 539 struct nbd_device *lo; 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 if (unlikely(!lo->sock)) { 551 printk(KERN_ERR "%s: Attempted send on closed socket\n", 552 lo->disk->disk_name); 553 req->errors++; 554 nbd_end_request(req); 555 spin_lock_irq(q->queue_lock); 556 continue; 557 } 558 559 spin_lock_irq(&lo->queue_lock); 560 list_add_tail(&req->queuelist, &lo->waiting_queue); 561 spin_unlock_irq(&lo->queue_lock); 562 563 wake_up(&lo->waiting_wq); 564 565 spin_lock_irq(q->queue_lock); 566 } 567 } 568 569 /* Must be called with tx_lock held */ 570 571 static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *lo, 572 unsigned int cmd, unsigned long arg) 573 { 574 switch (cmd) { 575 case NBD_DISCONNECT: { 576 struct request sreq; 577 578 printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); 579 580 blk_rq_init(NULL, &sreq); 581 sreq.cmd_type = REQ_TYPE_SPECIAL; 582 nbd_cmd(&sreq) = NBD_CMD_DISC; 583 if (!lo->sock) 584 return -EINVAL; 585 nbd_send_req(lo, &sreq); 586 return 0; 587 } 588 589 case NBD_CLEAR_SOCK: { 590 struct file *file; 591 592 lo->sock = NULL; 593 file = lo->file; 594 lo->file = NULL; 595 nbd_clear_que(lo); 596 BUG_ON(!list_empty(&lo->queue_head)); 597 if (file) 598 fput(file); 599 return 0; 600 } 601 602 case NBD_SET_SOCK: { 603 struct file *file; 604 if (lo->file) 605 return -EBUSY; 606 file = fget(arg); 607 if (file) { 608 struct inode *inode = file->f_path.dentry->d_inode; 609 if (S_ISSOCK(inode->i_mode)) { 610 lo->file = file; 611 lo->sock = SOCKET_I(inode); 612 if (max_part > 0) 613 bdev->bd_invalidated = 1; 614 return 0; 615 } else { 616 fput(file); 617 } 618 } 619 return -EINVAL; 620 } 621 622 case NBD_SET_BLKSIZE: 623 lo->blksize = arg; 624 lo->bytesize &= ~(lo->blksize-1); 625 bdev->bd_inode->i_size = lo->bytesize; 626 set_blocksize(bdev, lo->blksize); 627 set_capacity(lo->disk, lo->bytesize >> 9); 628 return 0; 629 630 case NBD_SET_SIZE: 631 lo->bytesize = arg & ~(lo->blksize-1); 632 bdev->bd_inode->i_size = lo->bytesize; 633 set_blocksize(bdev, lo->blksize); 634 set_capacity(lo->disk, lo->bytesize >> 9); 635 return 0; 636 637 case NBD_SET_TIMEOUT: 638 lo->xmit_timeout = arg * HZ; 639 return 0; 640 641 case NBD_SET_SIZE_BLOCKS: 642 lo->bytesize = ((u64) arg) * lo->blksize; 643 bdev->bd_inode->i_size = lo->bytesize; 644 set_blocksize(bdev, lo->blksize); 645 set_capacity(lo->disk, lo->bytesize >> 9); 646 return 0; 647 648 case NBD_DO_IT: { 649 struct task_struct *thread; 650 struct file *file; 651 int error; 652 653 if (lo->pid) 654 return -EBUSY; 655 if (!lo->file) 656 return -EINVAL; 657 658 mutex_unlock(&lo->tx_lock); 659 660 thread = kthread_create(nbd_thread, lo, lo->disk->disk_name); 661 if (IS_ERR(thread)) { 662 mutex_lock(&lo->tx_lock); 663 return PTR_ERR(thread); 664 } 665 wake_up_process(thread); 666 error = nbd_do_it(lo); 667 kthread_stop(thread); 668 669 mutex_lock(&lo->tx_lock); 670 if (error) 671 return error; 672 sock_shutdown(lo, 0); 673 file = lo->file; 674 lo->file = NULL; 675 nbd_clear_que(lo); 676 printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name); 677 if (file) 678 fput(file); 679 lo->bytesize = 0; 680 bdev->bd_inode->i_size = 0; 681 set_capacity(lo->disk, 0); 682 if (max_part > 0) 683 ioctl_by_bdev(bdev, BLKRRPART, 0); 684 return lo->harderror; 685 } 686 687 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; 694 695 case NBD_PRINT_DEBUG: 696 printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n", 697 bdev->bd_disk->disk_name, 698 lo->queue_head.next, lo->queue_head.prev, 699 &lo->queue_head); 700 return 0; 701 } 702 return -ENOTTY; 703 } 704 705 static int nbd_ioctl(struct block_device *bdev, fmode_t mode, 706 unsigned int cmd, unsigned long arg) 707 { 708 struct nbd_device *lo = bdev->bd_disk->private_data; 709 int error; 710 711 if (!capable(CAP_SYS_ADMIN)) 712 return -EPERM; 713 714 BUG_ON(lo->magic != LO_MAGIC); 715 716 /* Anyone capable of this syscall can do *real bad* things */ 717 dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", 718 lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); 719 720 mutex_lock(&lo->tx_lock); 721 error = __nbd_ioctl(bdev, lo, cmd, arg); 722 mutex_unlock(&lo->tx_lock); 723 724 return error; 725 } 726 727 static const struct block_device_operations nbd_fops = 728 { 729 .owner = THIS_MODULE, 730 .ioctl = nbd_ioctl, 731 }; 732 733 /* 734 * And here should be modules and kernel interface 735 * (Just smiley confuses emacs :-) 736 */ 737 738 static int __init nbd_init(void) 739 { 740 int err = -ENOMEM; 741 int i; 742 int part_shift; 743 744 BUILD_BUG_ON(sizeof(struct nbd_request) != 28); 745 746 if (max_part < 0) { 747 printk(KERN_CRIT "nbd: max_part must be >= 0\n"); 748 return -EINVAL; 749 } 750 751 nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); 752 if (!nbd_dev) 753 return -ENOMEM; 754 755 part_shift = 0; 756 if (max_part > 0) 757 part_shift = fls(max_part); 758 759 for (i = 0; i < nbds_max; i++) { 760 struct gendisk *disk = alloc_disk(1 << part_shift); 761 if (!disk) 762 goto out; 763 nbd_dev[i].disk = disk; 764 /* 765 * The new linux 2.5 block layer implementation requires 766 * every gendisk to have its very own request_queue struct. 767 * These structs are big so we dynamically allocate them. 768 */ 769 disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); 770 if (!disk->queue) { 771 put_disk(disk); 772 goto out; 773 } 774 /* 775 * Tell the block layer that we are not a rotational device 776 */ 777 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); 778 } 779 780 if (register_blkdev(NBD_MAJOR, "nbd")) { 781 err = -EIO; 782 goto out; 783 } 784 785 printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); 786 dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); 787 788 for (i = 0; i < nbds_max; i++) { 789 struct gendisk *disk = nbd_dev[i].disk; 790 nbd_dev[i].file = NULL; 791 nbd_dev[i].magic = LO_MAGIC; 792 nbd_dev[i].flags = 0; 793 INIT_LIST_HEAD(&nbd_dev[i].waiting_queue); 794 spin_lock_init(&nbd_dev[i].queue_lock); 795 INIT_LIST_HEAD(&nbd_dev[i].queue_head); 796 mutex_init(&nbd_dev[i].tx_lock); 797 init_waitqueue_head(&nbd_dev[i].active_wq); 798 init_waitqueue_head(&nbd_dev[i].waiting_wq); 799 nbd_dev[i].blksize = 1024; 800 nbd_dev[i].bytesize = 0; 801 disk->major = NBD_MAJOR; 802 disk->first_minor = i << part_shift; 803 disk->fops = &nbd_fops; 804 disk->private_data = &nbd_dev[i]; 805 sprintf(disk->disk_name, "nbd%d", i); 806 set_capacity(disk, 0); 807 add_disk(disk); 808 } 809 810 return 0; 811 out: 812 while (i--) { 813 blk_cleanup_queue(nbd_dev[i].disk->queue); 814 put_disk(nbd_dev[i].disk); 815 } 816 kfree(nbd_dev); 817 return err; 818 } 819 820 static void __exit nbd_cleanup(void) 821 { 822 int i; 823 for (i = 0; i < nbds_max; i++) { 824 struct gendisk *disk = nbd_dev[i].disk; 825 nbd_dev[i].magic = 0; 826 if (disk) { 827 del_gendisk(disk); 828 blk_cleanup_queue(disk->queue); 829 put_disk(disk); 830 } 831 } 832 unregister_blkdev(NBD_MAJOR, "nbd"); 833 kfree(nbd_dev); 834 printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); 835 } 836 837 module_init(nbd_init); 838 module_exit(nbd_cleanup); 839 840 MODULE_DESCRIPTION("Network Block Device"); 841 MODULE_LICENSE("GPL"); 842 843 module_param(nbds_max, int, 0444); 844 MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); 845 module_param(max_part, int, 0444); 846 MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)"); 847 #ifndef NDEBUG 848 module_param(debugflags, int, 0644); 849 MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); 850 #endif 851