diff options
Diffstat (limited to 'drivers/block/nbd.c')
| -rw-r--r-- | drivers/block/nbd.c | 829 |
1 files changed, 829 insertions, 0 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c new file mode 100644 index 0000000..92d6c9f --- /dev/null +++ b/drivers/block/nbd.c @@ -0,0 +1,829 @@ +/* + * Network block device - make block devices work over TCP + * + * Note that you can not swap over this thing, yet. Seems to work but + * deadlocks sometimes - you can not swap over TCP in general. + * + * Copyright 1997-2000 Pavel Machek <pavel@ucw.cz> + * Parts copyright 2001 Steven Whitehouse <steve@chygwyn.com> + * + * This file is released under GPLv2 or later. + * + * (part of code stolen from loop.c) + */ + +#include <linux/major.h> + +#include <linux/blkdev.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/fs.h> +#include <linux/bio.h> +#include <linux/stat.h> +#include <linux/errno.h> +#include <linux/file.h> +#include <linux/ioctl.h> +#include <linux/compiler.h> +#include <linux/err.h> +#include <linux/kernel.h> +#include <net/sock.h> +#include <linux/net.h> +#include <linux/kthread.h> + +#include <asm/uaccess.h> +#include <asm/system.h> +#include <asm/types.h> + +#include <linux/nbd.h> + +#define LO_MAGIC 0x68797548 + +#ifdef NDEBUG +#define dprintk(flags, fmt...) +#else /* NDEBUG */ +#define dprintk(flags, fmt...) do { \ + if (debugflags & (flags)) printk(KERN_DEBUG fmt); \ +} while (0) +#define DBG_IOCTL 0x0004 +#define DBG_INIT 0x0010 +#define DBG_EXIT 0x0020 +#define DBG_BLKDEV 0x0100 +#define DBG_RX 0x0200 +#define DBG_TX 0x0400 +static unsigned int debugflags; +#endif /* NDEBUG */ + +static unsigned int nbds_max = 16; +static struct nbd_device *nbd_dev; +static int max_part; + +/* + * Use just one lock (or at most 1 per NIC). Two arguments for this: + * 1. Each NIC is essentially a synchronization point for all servers + * accessed through that NIC so there's no need to have more locks + * than NICs anyway. + * 2. More locks lead to more "Dirty cache line bouncing" which will slow + * down each lock to the point where they're actually slower than just + * a single lock. + * Thanks go to Jens Axboe and Al Viro for their LKML emails explaining this! + */ +static DEFINE_SPINLOCK(nbd_lock); + +#ifndef NDEBUG +static const char *ioctl_cmd_to_ascii(int cmd) +{ + switch (cmd) { + case NBD_SET_SOCK: return "set-sock"; + case NBD_SET_BLKSIZE: return "set-blksize"; + case NBD_SET_SIZE: return "set-size"; + case NBD_DO_IT: return "do-it"; + case NBD_CLEAR_SOCK: return "clear-sock"; + case NBD_CLEAR_QUE: return "clear-que"; + case NBD_PRINT_DEBUG: return "print-debug"; + case NBD_SET_SIZE_BLOCKS: return "set-size-blocks"; + case NBD_DISCONNECT: return "disconnect"; + case BLKROSET: return "set-read-only"; + case BLKFLSBUF: return "flush-buffer-cache"; + } + return "unknown"; +} + +static const char *nbdcmd_to_ascii(int cmd) +{ + switch (cmd) { + case NBD_CMD_READ: return "read"; + case NBD_CMD_WRITE: return "write"; + case NBD_CMD_DISC: return "disconnect"; + } + return "invalid"; +} +#endif /* NDEBUG */ + +static void nbd_end_request(struct request *req) +{ + int error = req->errors ? -EIO : 0; + struct request_queue *q = req->q; + unsigned long flags; + + dprintk(DBG_BLKDEV, "%s: request %p: %s\n", req->rq_disk->disk_name, + req, error ? "failed" : "done"); + + spin_lock_irqsave(q->queue_lock, flags); + __blk_end_request(req, error, req->nr_sectors << 9); + spin_unlock_irqrestore(q->queue_lock, flags); +} + +static void sock_shutdown(struct nbd_device *lo, int lock) +{ + /* Forcibly shutdown the socket causing all listeners + * to error + * + * FIXME: This code is duplicated from sys_shutdown, but + * there should be a more generic interface rather than + * calling socket ops directly here */ + if (lock) + mutex_lock(&lo->tx_lock); + if (lo->sock) { + printk(KERN_WARNING "%s: shutting down socket\n", + lo->disk->disk_name); + kernel_sock_shutdown(lo->sock, SHUT_RDWR); + lo->sock = NULL; + } + if (lock) + mutex_unlock(&lo->tx_lock); +} + +static void nbd_xmit_timeout(unsigned long arg) +{ + struct task_struct *task = (struct task_struct *)arg; + + printk(KERN_WARNING "nbd: killing hung xmit (%s, pid: %d)\n", + task->comm, task->pid); + force_sig(SIGKILL, task); +} + +/* + * Send or receive packet. + */ +static int sock_xmit(struct nbd_device *lo, int send, void *buf, int size, + int msg_flags) +{ + struct socket *sock = lo->sock; + int result; + struct msghdr msg; + struct kvec iov; + sigset_t blocked, oldset; + + if (unlikely(!sock)) { + printk(KERN_ERR "%s: Attempted %s on closed socket in sock_xmit\n", + lo->disk->disk_name, (send ? "send" : "recv")); + return -EINVAL; + } + + /* Allow interception of SIGKILL only + * Don't allow other signals to interrupt the transmission */ + siginitsetinv(&blocked, sigmask(SIGKILL)); + sigprocmask(SIG_SETMASK, &blocked, &oldset); + + do { + sock->sk->sk_allocation = GFP_NOIO; + iov.iov_base = buf; + iov.iov_len = size; + msg.msg_name = NULL; + msg.msg_namelen = 0; + msg.msg_control = NULL; + msg.msg_controllen = 0; + msg.msg_flags = msg_flags | MSG_NOSIGNAL; + + if (send) { + struct timer_list ti; + + if (lo->xmit_timeout) { + init_timer(&ti); + ti.function = nbd_xmit_timeout; + ti.data = (unsigned long)current; + ti.expires = jiffies + lo->xmit_timeout; + add_timer(&ti); + } + result = kernel_sendmsg(sock, &msg, &iov, 1, size); + if (lo->xmit_timeout) + del_timer_sync(&ti); + } else + result = kernel_recvmsg(sock, &msg, &iov, 1, size, 0); + + if (signal_pending(current)) { + siginfo_t info; + printk(KERN_WARNING "nbd (pid %d: %s) got signal %d\n", + task_pid_nr(current), current->comm, + dequeue_signal_lock(current, ¤t->blocked, &info)); + result = -EINTR; + sock_shutdown(lo, !send); + break; + } + + if (result <= 0) { + if (result == 0) + result = -EPIPE; /* short read */ + break; + } + size -= result; + buf += result; + } while (size > 0); + + sigprocmask(SIG_SETMASK, &oldset, NULL); + + return result; +} + +static inline int sock_send_bvec(struct nbd_device *lo, struct bio_vec *bvec, + int flags) +{ + int result; + void *kaddr = kmap(bvec->bv_page); + result = sock_xmit(lo, 1, kaddr + bvec->bv_offset, bvec->bv_len, flags); + kunmap(bvec->bv_page); + return result; +} + +/* always call with the tx_lock held */ +static int nbd_send_req(struct nbd_device *lo, struct request *req) +{ + int result, flags; + struct nbd_request request; + unsigned long size = req->nr_sectors << 9; + + request.magic = htonl(NBD_REQUEST_MAGIC); + request.type = htonl(nbd_cmd(req)); + request.from = cpu_to_be64((u64) req->sector << 9); + request.len = htonl(size); + memcpy(request.handle, &req, sizeof(req)); + + dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%luB)\n", + lo->disk->disk_name, req, + nbdcmd_to_ascii(nbd_cmd(req)), + (unsigned long long)req->sector << 9, + req->nr_sectors << 9); + result = sock_xmit(lo, 1, &request, sizeof(request), + (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); + if (result <= 0) { + printk(KERN_ERR "%s: Send control failed (result %d)\n", + lo->disk->disk_name, result); + goto error_out; + } + + if (nbd_cmd(req) == NBD_CMD_WRITE) { + struct req_iterator iter; + struct bio_vec *bvec; + /* + * we are really probing at internals to determine + * whether to set MSG_MORE or not... + */ + rq_for_each_segment(bvec, req, iter) { + flags = 0; + if (!rq_iter_last(req, iter)) + flags = MSG_MORE; + dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n", + lo->disk->disk_name, req, bvec->bv_len); + result = sock_send_bvec(lo, bvec, flags); + if (result <= 0) { + printk(KERN_ERR "%s: Send data failed (result %d)\n", + lo->disk->disk_name, result); + goto error_out; + } + } + } + return 0; + +error_out: + return 1; +} + +static struct request *nbd_find_request(struct nbd_device *lo, + struct request *xreq) +{ + struct request *req, *tmp; + int err; + + err = wait_event_interruptible(lo->active_wq, lo->active_req != xreq); + if (unlikely(err)) + goto out; + + spin_lock(&lo->queue_lock); + list_for_each_entry_safe(req, tmp, &lo->queue_head, queuelist) { + if (req != xreq) + continue; + list_del_init(&req->queuelist); + spin_unlock(&lo->queue_lock); + return req; + } + spin_unlock(&lo->queue_lock); + + err = -ENOENT; + +out: + return ERR_PTR(err); +} + +static inline int sock_recv_bvec(struct nbd_device *lo, struct bio_vec *bvec) +{ + int result; + void *kaddr = kmap(bvec->bv_page); + result = sock_xmit(lo, 0, kaddr + bvec->bv_offset, bvec->bv_len, + MSG_WAITALL); + kunmap(bvec->bv_page); + return result; +} + +/* NULL returned = something went wrong, inform userspace */ +static struct request *nbd_read_stat(struct nbd_device *lo) +{ + int result; + struct nbd_reply reply; + struct request *req; + + reply.magic = 0; + result = sock_xmit(lo, 0, &reply, sizeof(reply), MSG_WAITALL); + if (result <= 0) { + printk(KERN_ERR "%s: Receive control failed (result %d)\n", + lo->disk->disk_name, result); + goto harderror; + } + + if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { + printk(KERN_ERR "%s: Wrong magic (0x%lx)\n", + lo->disk->disk_name, + (unsigned long)ntohl(reply.magic)); + result = -EPROTO; + goto harderror; + } + + req = nbd_find_request(lo, *(struct request **)reply.handle); + if (IS_ERR(req)) { + result = PTR_ERR(req); + if (result != -ENOENT) + goto harderror; + + printk(KERN_ERR "%s: Unexpected reply (%p)\n", + lo->disk->disk_name, reply.handle); + result = -EBADR; + goto harderror; + } + + if (ntohl(reply.error)) { + printk(KERN_ERR "%s: Other side returned error (%d)\n", + lo->disk->disk_name, ntohl(reply.error)); + req->errors++; + return req; + } + + dprintk(DBG_RX, "%s: request %p: got reply\n", + lo->disk->disk_name, req); + if (nbd_cmd(req) == NBD_CMD_READ) { + struct req_iterator iter; + struct bio_vec *bvec; + + rq_for_each_segment(bvec, req, iter) { + result = sock_recv_bvec(lo, bvec); + if (result <= 0) { + printk(KERN_ERR "%s: Receive data failed (result %d)\n", + lo->disk->disk_name, result); + req->errors++; + return req; + } + dprintk(DBG_RX, "%s: request %p: got %d bytes data\n", + lo->disk->disk_name, req, bvec->bv_len); + } + } + return req; +harderror: + lo->harderror = result; + return NULL; +} + +static ssize_t pid_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct gendisk *disk = dev_to_disk(dev); + + return sprintf(buf, "%ld\n", + (long) ((struct nbd_device *)disk->private_data)->pid); +} + +static struct device_attribute pid_attr = { + .attr = { .name = "pid", .mode = S_IRUGO}, + .show = pid_show, +}; + +static int nbd_do_it(struct nbd_device *lo) +{ + struct request *req; + int ret; + + BUG_ON(lo->magic != LO_MAGIC); + + lo->pid = current->pid; + ret = sysfs_create_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); + if (ret) { + printk(KERN_ERR "nbd: sysfs_create_file failed!"); + lo->pid = 0; + return ret; + } + + while ((req = nbd_read_stat(lo)) != NULL) + nbd_end_request(req); + + sysfs_remove_file(&disk_to_dev(lo->disk)->kobj, &pid_attr.attr); + lo->pid = 0; + return 0; +} + +static void nbd_clear_que(struct nbd_device *lo) +{ + struct request *req; + + BUG_ON(lo->magic != LO_MAGIC); + + /* + * Because we have set lo->sock to NULL under the tx_lock, all + * modifications to the list must have completed by now. For + * the same reason, the active_req must be NULL. + * + * As a consequence, we don't need to take the spin lock while + * purging the list here. + */ + BUG_ON(lo->sock); + BUG_ON(lo->active_req); + + while (!list_empty(&lo->queue_head)) { + req = list_entry(lo->queue_head.next, struct request, + queuelist); + list_del_init(&req->queuelist); + req->errors++; + nbd_end_request(req); + } +} + + +static void nbd_handle_req(struct nbd_device *lo, struct request *req) +{ + if (!blk_fs_request(req)) + goto error_out; + + nbd_cmd(req) = NBD_CMD_READ; + if (rq_data_dir(req) == WRITE) { + nbd_cmd(req) = NBD_CMD_WRITE; + if (lo->flags & NBD_READ_ONLY) { + printk(KERN_ERR "%s: Write on read-only\n", + lo->disk->disk_name); + goto error_out; + } + } + + req->errors = 0; + + mutex_lock(&lo->tx_lock); + if (unlikely(!lo->sock)) { + mutex_unlock(&lo->tx_lock); + printk(KERN_ERR "%s: Attempted send on closed socket\n", + lo->disk->disk_name); + req->errors++; + nbd_end_request(req); + return; + } + + lo->active_req = req; + + if (nbd_send_req(lo, req) != 0) { + printk(KERN_ERR "%s: Request send failed\n", + lo->disk->disk_name); + req->errors++; + nbd_end_request(req); + } else { + spin_lock(&lo->queue_lock); + list_add(&req->queuelist, &lo->queue_head); + spin_unlock(&lo->queue_lock); + } + + lo->active_req = NULL; + mutex_unlock(&lo->tx_lock); + wake_up_all(&lo->active_wq); + + return; + +error_out: + req->errors++; + nbd_end_request(req); +} + +static int nbd_thread(void *data) +{ + struct nbd_device *lo = data; + struct request *req; + + set_user_nice(current, -20); + while (!kthread_should_stop() || !list_empty(&lo->waiting_queue)) { + /* wait for something to do */ + wait_event_interruptible(lo->waiting_wq, + kthread_should_stop() || + !list_empty(&lo->waiting_queue)); + + /* extract request */ + if (list_empty(&lo->waiting_queue)) + continue; + + spin_lock_irq(&lo->queue_lock); + req = list_entry(lo->waiting_queue.next, struct request, + queuelist); + list_del_init(&req->queuelist); + spin_unlock_irq(&lo->queue_lock); + + /* handle request */ + nbd_handle_req(lo, req); + } + return 0; +} + +/* + * We always wait for result of write, for now. It would be nice to make it optional + * in future + * if ((rq_data_dir(req) == WRITE) && (lo->flags & NBD_WRITE_NOCHK)) + * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } + */ + +static void do_nbd_request(struct request_queue * q) +{ + struct request *req; + + while ((req = elv_next_request(q)) != NULL) { + struct nbd_device *lo; + + blkdev_dequeue_request(req); + + spin_unlock_irq(q->queue_lock); + + dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n", + req->rq_disk->disk_name, req, req->cmd_type); + + lo = req->rq_disk->private_data; + + BUG_ON(lo->magic != LO_MAGIC); + + if (unlikely(!lo->sock)) { + printk(KERN_ERR "%s: Attempted send on closed socket\n", + lo->disk->disk_name); + req->errors++; + nbd_end_request(req); + spin_lock_irq(q->queue_lock); + continue; + } + + spin_lock_irq(&lo->queue_lock); + list_add_tail(&req->queuelist, &lo->waiting_queue); + spin_unlock_irq(&lo->queue_lock); + + wake_up(&lo->waiting_wq); + + spin_lock_irq(q->queue_lock); + } +} + +static int nbd_ioctl(struct block_device *bdev, fmode_t mode, + unsigned int cmd, unsigned long arg) +{ + struct nbd_device *lo = bdev->bd_disk->private_data; + struct file *file; + int error; + struct request sreq ; + struct task_struct *thread; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + BUG_ON(lo->magic != LO_MAGIC); + + /* Anyone capable of this syscall can do *real bad* things */ + dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n", + lo->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg); + + switch (cmd) { + case NBD_DISCONNECT: + printk(KERN_INFO "%s: NBD_DISCONNECT\n", lo->disk->disk_name); + blk_rq_init(NULL, &sreq); + sreq.cmd_type = REQ_TYPE_SPECIAL; + nbd_cmd(&sreq) = NBD_CMD_DISC; + /* + * Set these to sane values in case server implementation + * fails to check the request type first and also to keep + * debugging output cleaner. + */ + sreq.sector = 0; + sreq.nr_sectors = 0; + if (!lo->sock) + return -EINVAL; + mutex_lock(&lo->tx_lock); + nbd_send_req(lo, &sreq); + mutex_unlock(&lo->tx_lock); + return 0; + + case NBD_CLEAR_SOCK: + error = 0; + mutex_lock(&lo->tx_lock); + lo->sock = NULL; + mutex_unlock(&lo->tx_lock); + file = lo->file; + lo->file = NULL; + nbd_clear_que(lo); + BUG_ON(!list_empty(&lo->queue_head)); + if (file) + fput(file); + return error; + case NBD_SET_SOCK: + if (lo->file) + return -EBUSY; + error = -EINVAL; + file = fget(arg); + if (file) { + struct inode *inode = file->f_path.dentry->d_inode; + if (S_ISSOCK(inode->i_mode)) { + lo->file = file; + lo->sock = SOCKET_I(inode); + if (max_part > 0) + bdev->bd_invalidated = 1; + error = 0; + } else { + fput(file); + } + } + return error; + case NBD_SET_BLKSIZE: + lo->blksize = arg; + lo->bytesize &= ~(lo->blksize-1); + bdev->bd_inode->i_size = lo->bytesize; + set_blocksize(bdev, lo->blksize); + set_capacity(lo->disk, lo->bytesize >> 9); + return 0; + case NBD_SET_SIZE: + lo->bytesize = arg & ~(lo->blksize-1); + bdev->bd_inode->i_size = lo->bytesize; + set_blocksize(bdev, lo->blksize); + set_capacity(lo->disk, lo->bytesize >> 9); + return 0; + case NBD_SET_TIMEOUT: + lo->xmit_timeout = arg * HZ; + return 0; + case NBD_SET_SIZE_BLOCKS: + lo->bytesize = ((u64) arg) * lo->blksize; + bdev->bd_inode->i_size = lo->bytesize; + set_blocksize(bdev, lo->blksize); + set_capacity(lo->disk, lo->bytesize >> 9); + return 0; + case NBD_DO_IT: + if (lo->pid) + return -EBUSY; + if (!lo->file) + return -EINVAL; + thread = kthread_create(nbd_thread, lo, lo->disk->disk_name); + if (IS_ERR(thread)) + return PTR_ERR(thread); + wake_up_process(thread); + error = nbd_do_it(lo); + kthread_stop(thread); + if (error) + return error; + sock_shutdown(lo, 1); + file = lo->file; + lo->file = NULL; + nbd_clear_que(lo); + printk(KERN_WARNING "%s: queue cleared\n", lo->disk->disk_name); + if (file) + fput(file); + lo->bytesize = 0; + bdev->bd_inode->i_size = 0; + set_capacity(lo->disk, 0); + if (max_part > 0) + ioctl_by_bdev(bdev, BLKRRPART, 0); + return lo->harderror; + case NBD_CLEAR_QUE: + /* + * This is for compatibility only. The queue is always cleared + * by NBD_DO_IT or NBD_CLEAR_SOCK. + */ + BUG_ON(!lo->sock && !list_empty(&lo->queue_head)); + return 0; + case NBD_PRINT_DEBUG: + printk(KERN_INFO "%s: next = %p, prev = %p, head = %p\n", + bdev->bd_disk->disk_name, + lo->queue_head.next, lo->queue_head.prev, + &lo->queue_head); + return 0; + } + return -EINVAL; +} + +static struct block_device_operations nbd_fops = +{ + .owner = THIS_MODULE, + .locked_ioctl = nbd_ioctl, +}; + +/* + * And here should be modules and kernel interface + * (Just smiley confuses emacs :-) + */ + +static int __init nbd_init(void) +{ + int err = -ENOMEM; + int i; + int part_shift; + + BUILD_BUG_ON(sizeof(struct nbd_request) != 28); + + if (max_part < 0) { + printk(KERN_CRIT "nbd: max_part must be >= 0\n"); + return -EINVAL; + } + + nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); + if (!nbd_dev) + return -ENOMEM; + + part_shift = 0; + if (max_part > 0) + part_shift = fls(max_part); + + for (i = 0; i < nbds_max; i++) { + struct gendisk *disk = alloc_disk(1 << part_shift); + elevator_t *old_e; + if (!disk) + goto out; + nbd_dev[i].disk = disk; + /* + * The new linux 2.5 block layer implementation requires + * every gendisk to have its very own request_queue struct. + * These structs are big so we dynamically allocate them. + */ + disk->queue = blk_init_queue(do_nbd_request, &nbd_lock); + if (!disk->queue) { + put_disk(disk); + goto out; + } + old_e = disk->queue->elevator; + if (elevator_init(disk->queue, "deadline") == 0 || + elevator_init(disk->queue, "noop") == 0) { + elevator_exit(old_e); + } + } + + if (register_blkdev(NBD_MAJOR, "nbd")) { + err = -EIO; + goto out; + } + + printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); + dprintk(DBG_INIT, "nbd: debugflags=0x%x\n", debugflags); + + for (i = 0; i < nbds_max; i++) { + struct gendisk *disk = nbd_dev[i].disk; + nbd_dev[i].file = NULL; + nbd_dev[i].magic = LO_MAGIC; + nbd_dev[i].flags = 0; + INIT_LIST_HEAD(&nbd_dev[i].waiting_queue); + spin_lock_init(&nbd_dev[i].queue_lock); + INIT_LIST_HEAD(&nbd_dev[i].queue_head); + mutex_init(&nbd_dev[i].tx_lock); + init_waitqueue_head(&nbd_dev[i].active_wq); + init_waitqueue_head(&nbd_dev[i].waiting_wq); + nbd_dev[i].blksize = 1024; + nbd_dev[i].bytesize = 0; + disk->major = NBD_MAJOR; + disk->first_minor = i << part_shift; + disk->fops = &nbd_fops; + disk->private_data = &nbd_dev[i]; + sprintf(disk->disk_name, "nbd%d", i); + set_capacity(disk, 0); + add_disk(disk); + } + + return 0; +out: + while (i--) { + blk_cleanup_queue(nbd_dev[i].disk->queue); + put_disk(nbd_dev[i].disk); + } + kfree(nbd_dev); + return err; +} + +static void __exit nbd_cleanup(void) +{ + int i; + for (i = 0; i < nbds_max; i++) { + struct gendisk *disk = nbd_dev[i].disk; + nbd_dev[i].magic = 0; + if (disk) { + del_gendisk(disk); + blk_cleanup_queue(disk->queue); + put_disk(disk); + } + } + unregister_blkdev(NBD_MAJOR, "nbd"); + kfree(nbd_dev); + printk(KERN_INFO "nbd: unregistered device at major %d\n", NBD_MAJOR); +} + +module_init(nbd_init); +module_exit(nbd_cleanup); + +MODULE_DESCRIPTION("Network Block Device"); +MODULE_LICENSE("GPL"); + +module_param(nbds_max, int, 0444); +MODULE_PARM_DESC(nbds_max, "number of network block devices to initialize (default: 16)"); +module_param(max_part, int, 0444); +MODULE_PARM_DESC(max_part, "number of partitions per device (default: 0)"); +#ifndef NDEBUG +module_param(debugflags, int, 0644); +MODULE_PARM_DESC(debugflags, "flags for controlling debug output"); +#endif |
