diff options
Diffstat (limited to 'kernel/drivers/block/nbd.c')
| -rw-r--r-- | kernel/drivers/block/nbd.c | 896 |
1 files changed, 896 insertions, 0 deletions
diff --git a/kernel/drivers/block/nbd.c b/kernel/drivers/block/nbd.c new file mode 100644 index 000000000..39e5f7fae --- /dev/null +++ b/kernel/drivers/block/nbd.c @@ -0,0 +1,896 @@ +/* + * 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, 2008 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/mutex.h> +#include <linux/compiler.h> +#include <linux/err.h> +#include <linux/kernel.h> +#include <linux/slab.h> +#include <net/sock.h> +#include <linux/net.h> +#include <linux/kthread.h> +#include <linux/types.h> + +#include <asm/uaccess.h> +#include <asm/types.h> + +#include <linux/nbd.h> + +struct nbd_device { + int flags; + int harderror; /* Code of hard error */ + struct socket * sock; /* If == NULL, device is not ready, yet */ + int magic; + + spinlock_t queue_lock; + struct list_head queue_head; /* Requests waiting result */ + struct request *active_req; + wait_queue_head_t active_wq; + struct list_head waiting_queue; /* Requests to be sent */ + wait_queue_head_t waiting_wq; + + struct mutex tx_lock; + struct gendisk *disk; + int blksize; + loff_t bytesize; + pid_t pid; /* pid of nbd-client, if attached */ + int xmit_timeout; + int disconnect; /* a disconnect has been requested by user */ +}; + +#define NBD_MAGIC 0x68797548 + +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); + +static inline struct device *nbd_to_dev(struct nbd_device *nbd) +{ + return disk_to_dev(nbd->disk); +} + +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"; + case NBD_CMD_FLUSH: return "flush"; + case NBD_CMD_TRIM: return "trim/discard"; + } + return "invalid"; +} + +static void nbd_end_request(struct nbd_device *nbd, struct request *req) +{ + int error = req->errors ? -EIO : 0; + struct request_queue *q = req->q; + unsigned long flags; + + dev_dbg(nbd_to_dev(nbd), "request %p: %s\n", req, + error ? "failed" : "done"); + + spin_lock_irqsave(q->queue_lock, flags); + __blk_end_request_all(req, error); + spin_unlock_irqrestore(q->queue_lock, flags); +} + +/* + * Forcibly shutdown the socket causing all listeners to error + */ +static void sock_shutdown(struct nbd_device *nbd, int lock) +{ + if (lock) + mutex_lock(&nbd->tx_lock); + if (nbd->sock) { + dev_warn(disk_to_dev(nbd->disk), "shutting down socket\n"); + kernel_sock_shutdown(nbd->sock, SHUT_RDWR); + nbd->sock = NULL; + } + if (lock) + mutex_unlock(&nbd->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 *nbd, int send, void *buf, int size, + int msg_flags) +{ + struct socket *sock = nbd->sock; + int result; + struct msghdr msg; + struct kvec iov; + sigset_t blocked, oldset; + unsigned long pflags = current->flags; + + if (unlikely(!sock)) { + dev_err(disk_to_dev(nbd->disk), + "Attempted %s on closed socket in sock_xmit\n", + (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); + + current->flags |= PF_MEMALLOC; + do { + sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC; + 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 (nbd->xmit_timeout) { + init_timer(&ti); + ti.function = nbd_xmit_timeout; + ti.data = (unsigned long)current; + ti.expires = jiffies + nbd->xmit_timeout; + add_timer(&ti); + } + result = kernel_sendmsg(sock, &msg, &iov, 1, size); + if (nbd->xmit_timeout) + del_timer_sync(&ti); + } else + result = kernel_recvmsg(sock, &msg, &iov, 1, size, + msg.msg_flags); + + 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(nbd, !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); + tsk_restore_flags(current, pflags, PF_MEMALLOC); + + return result; +} + +static inline int sock_send_bvec(struct nbd_device *nbd, struct bio_vec *bvec, + int flags) +{ + int result; + void *kaddr = kmap(bvec->bv_page); + result = sock_xmit(nbd, 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 *nbd, struct request *req) +{ + int result, flags; + struct nbd_request request; + unsigned long size = blk_rq_bytes(req); + + memset(&request, 0, sizeof(request)); + request.magic = htonl(NBD_REQUEST_MAGIC); + request.type = htonl(nbd_cmd(req)); + + if (nbd_cmd(req) != NBD_CMD_FLUSH && nbd_cmd(req) != NBD_CMD_DISC) { + request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9); + request.len = htonl(size); + } + memcpy(request.handle, &req, sizeof(req)); + + dev_dbg(nbd_to_dev(nbd), "request %p: sending control (%s@%llu,%uB)\n", + req, nbdcmd_to_ascii(nbd_cmd(req)), + (unsigned long long)blk_rq_pos(req) << 9, blk_rq_bytes(req)); + result = sock_xmit(nbd, 1, &request, sizeof(request), + (nbd_cmd(req) == NBD_CMD_WRITE) ? MSG_MORE : 0); + if (result <= 0) { + dev_err(disk_to_dev(nbd->disk), + "Send control failed (result %d)\n", result); + return -EIO; + } + + 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(bvec, iter)) + flags = MSG_MORE; + dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n", + req, bvec.bv_len); + result = sock_send_bvec(nbd, &bvec, flags); + if (result <= 0) { + dev_err(disk_to_dev(nbd->disk), + "Send data failed (result %d)\n", + result); + return -EIO; + } + } + } + return 0; +} + +static struct request *nbd_find_request(struct nbd_device *nbd, + struct request *xreq) +{ + struct request *req, *tmp; + int err; + + err = wait_event_interruptible(nbd->active_wq, nbd->active_req != xreq); + if (unlikely(err)) + return ERR_PTR(err); + + spin_lock(&nbd->queue_lock); + list_for_each_entry_safe(req, tmp, &nbd->queue_head, queuelist) { + if (req != xreq) + continue; + list_del_init(&req->queuelist); + spin_unlock(&nbd->queue_lock); + return req; + } + spin_unlock(&nbd->queue_lock); + + return ERR_PTR(-ENOENT); +} + +static inline int sock_recv_bvec(struct nbd_device *nbd, struct bio_vec *bvec) +{ + int result; + void *kaddr = kmap(bvec->bv_page); + result = sock_xmit(nbd, 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 *nbd) +{ + int result; + struct nbd_reply reply; + struct request *req; + + reply.magic = 0; + result = sock_xmit(nbd, 0, &reply, sizeof(reply), MSG_WAITALL); + if (result <= 0) { + dev_err(disk_to_dev(nbd->disk), + "Receive control failed (result %d)\n", result); + goto harderror; + } + + if (ntohl(reply.magic) != NBD_REPLY_MAGIC) { + dev_err(disk_to_dev(nbd->disk), "Wrong magic (0x%lx)\n", + (unsigned long)ntohl(reply.magic)); + result = -EPROTO; + goto harderror; + } + + req = nbd_find_request(nbd, *(struct request **)reply.handle); + if (IS_ERR(req)) { + result = PTR_ERR(req); + if (result != -ENOENT) + goto harderror; + + dev_err(disk_to_dev(nbd->disk), "Unexpected reply (%p)\n", + reply.handle); + result = -EBADR; + goto harderror; + } + + if (ntohl(reply.error)) { + dev_err(disk_to_dev(nbd->disk), "Other side returned error (%d)\n", + ntohl(reply.error)); + req->errors++; + return req; + } + + dev_dbg(nbd_to_dev(nbd), "request %p: got reply\n", 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(nbd, &bvec); + if (result <= 0) { + dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n", + result); + req->errors++; + return req; + } + dev_dbg(nbd_to_dev(nbd), "request %p: got %d bytes data\n", + req, bvec.bv_len); + } + } + return req; +harderror: + nbd->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 *nbd) +{ + struct request *req; + int ret; + + BUG_ON(nbd->magic != NBD_MAGIC); + + sk_set_memalloc(nbd->sock->sk); + nbd->pid = task_pid_nr(current); + ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr); + if (ret) { + dev_err(disk_to_dev(nbd->disk), "device_create_file failed!\n"); + nbd->pid = 0; + return ret; + } + + while ((req = nbd_read_stat(nbd)) != NULL) + nbd_end_request(nbd, req); + + device_remove_file(disk_to_dev(nbd->disk), &pid_attr); + nbd->pid = 0; + return 0; +} + +static void nbd_clear_que(struct nbd_device *nbd) +{ + struct request *req; + + BUG_ON(nbd->magic != NBD_MAGIC); + + /* + * Because we have set nbd->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(nbd->sock); + BUG_ON(nbd->active_req); + + while (!list_empty(&nbd->queue_head)) { + req = list_entry(nbd->queue_head.next, struct request, + queuelist); + list_del_init(&req->queuelist); + req->errors++; + nbd_end_request(nbd, req); + } + + while (!list_empty(&nbd->waiting_queue)) { + req = list_entry(nbd->waiting_queue.next, struct request, + queuelist); + list_del_init(&req->queuelist); + req->errors++; + nbd_end_request(nbd, req); + } +} + + +static void nbd_handle_req(struct nbd_device *nbd, struct request *req) +{ + if (req->cmd_type != REQ_TYPE_FS) + goto error_out; + + nbd_cmd(req) = NBD_CMD_READ; + if (rq_data_dir(req) == WRITE) { + if ((req->cmd_flags & REQ_DISCARD)) { + WARN_ON(!(nbd->flags & NBD_FLAG_SEND_TRIM)); + nbd_cmd(req) = NBD_CMD_TRIM; + } else + nbd_cmd(req) = NBD_CMD_WRITE; + if (nbd->flags & NBD_FLAG_READ_ONLY) { + dev_err(disk_to_dev(nbd->disk), + "Write on read-only\n"); + goto error_out; + } + } + + if (req->cmd_flags & REQ_FLUSH) { + BUG_ON(unlikely(blk_rq_sectors(req))); + nbd_cmd(req) = NBD_CMD_FLUSH; + } + + req->errors = 0; + + mutex_lock(&nbd->tx_lock); + if (unlikely(!nbd->sock)) { + mutex_unlock(&nbd->tx_lock); + dev_err(disk_to_dev(nbd->disk), + "Attempted send on closed socket\n"); + goto error_out; + } + + nbd->active_req = req; + + if (nbd_send_req(nbd, req) != 0) { + dev_err(disk_to_dev(nbd->disk), "Request send failed\n"); + req->errors++; + nbd_end_request(nbd, req); + } else { + spin_lock(&nbd->queue_lock); + list_add_tail(&req->queuelist, &nbd->queue_head); + spin_unlock(&nbd->queue_lock); + } + + nbd->active_req = NULL; + mutex_unlock(&nbd->tx_lock); + wake_up_all(&nbd->active_wq); + + return; + +error_out: + req->errors++; + nbd_end_request(nbd, req); +} + +static int nbd_thread(void *data) +{ + struct nbd_device *nbd = data; + struct request *req; + + set_user_nice(current, MIN_NICE); + while (!kthread_should_stop() || !list_empty(&nbd->waiting_queue)) { + /* wait for something to do */ + wait_event_interruptible(nbd->waiting_wq, + kthread_should_stop() || + !list_empty(&nbd->waiting_queue)); + + /* extract request */ + if (list_empty(&nbd->waiting_queue)) + continue; + + spin_lock_irq(&nbd->queue_lock); + req = list_entry(nbd->waiting_queue.next, struct request, + queuelist); + list_del_init(&req->queuelist); + spin_unlock_irq(&nbd->queue_lock); + + /* handle request */ + nbd_handle_req(nbd, 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) && (nbd->flags & NBD_WRITE_NOCHK)) + * { printk( "Warning: Ignoring result!\n"); nbd_end_request( req ); } + */ + +static void do_nbd_request(struct request_queue *q) + __releases(q->queue_lock) __acquires(q->queue_lock) +{ + struct request *req; + + while ((req = blk_fetch_request(q)) != NULL) { + struct nbd_device *nbd; + + spin_unlock_irq(q->queue_lock); + + nbd = req->rq_disk->private_data; + + BUG_ON(nbd->magic != NBD_MAGIC); + + dev_dbg(nbd_to_dev(nbd), "request %p: dequeued (flags=%x)\n", + req, req->cmd_type); + + if (unlikely(!nbd->sock)) { + dev_err(disk_to_dev(nbd->disk), + "Attempted send on closed socket\n"); + req->errors++; + nbd_end_request(nbd, req); + spin_lock_irq(q->queue_lock); + continue; + } + + spin_lock_irq(&nbd->queue_lock); + list_add_tail(&req->queuelist, &nbd->waiting_queue); + spin_unlock_irq(&nbd->queue_lock); + + wake_up(&nbd->waiting_wq); + + spin_lock_irq(q->queue_lock); + } +} + +/* Must be called with tx_lock held */ + +static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, + unsigned int cmd, unsigned long arg) +{ + switch (cmd) { + case NBD_DISCONNECT: { + struct request sreq; + + dev_info(disk_to_dev(nbd->disk), "NBD_DISCONNECT\n"); + if (!nbd->sock) + return -EINVAL; + + mutex_unlock(&nbd->tx_lock); + fsync_bdev(bdev); + mutex_lock(&nbd->tx_lock); + blk_rq_init(NULL, &sreq); + sreq.cmd_type = REQ_TYPE_SPECIAL; + nbd_cmd(&sreq) = NBD_CMD_DISC; + + /* Check again after getting mutex back. */ + if (!nbd->sock) + return -EINVAL; + + nbd->disconnect = 1; + + nbd_send_req(nbd, &sreq); + return 0; + } + + case NBD_CLEAR_SOCK: { + struct socket *sock = nbd->sock; + nbd->sock = NULL; + nbd_clear_que(nbd); + BUG_ON(!list_empty(&nbd->queue_head)); + BUG_ON(!list_empty(&nbd->waiting_queue)); + kill_bdev(bdev); + if (sock) + sockfd_put(sock); + return 0; + } + + case NBD_SET_SOCK: { + struct socket *sock; + int err; + if (nbd->sock) + return -EBUSY; + sock = sockfd_lookup(arg, &err); + if (sock) { + nbd->sock = sock; + if (max_part > 0) + bdev->bd_invalidated = 1; + nbd->disconnect = 0; /* we're connected now */ + return 0; + } + return -EINVAL; + } + + case NBD_SET_BLKSIZE: + nbd->blksize = arg; + nbd->bytesize &= ~(nbd->blksize-1); + bdev->bd_inode->i_size = nbd->bytesize; + set_blocksize(bdev, nbd->blksize); + set_capacity(nbd->disk, nbd->bytesize >> 9); + return 0; + + case NBD_SET_SIZE: + nbd->bytesize = arg & ~(nbd->blksize-1); + bdev->bd_inode->i_size = nbd->bytesize; + set_blocksize(bdev, nbd->blksize); + set_capacity(nbd->disk, nbd->bytesize >> 9); + return 0; + + case NBD_SET_TIMEOUT: + nbd->xmit_timeout = arg * HZ; + return 0; + + case NBD_SET_FLAGS: + nbd->flags = arg; + return 0; + + case NBD_SET_SIZE_BLOCKS: + nbd->bytesize = ((u64) arg) * nbd->blksize; + bdev->bd_inode->i_size = nbd->bytesize; + set_blocksize(bdev, nbd->blksize); + set_capacity(nbd->disk, nbd->bytesize >> 9); + return 0; + + case NBD_DO_IT: { + struct task_struct *thread; + struct socket *sock; + int error; + + if (nbd->pid) + return -EBUSY; + if (!nbd->sock) + return -EINVAL; + + mutex_unlock(&nbd->tx_lock); + + if (nbd->flags & NBD_FLAG_READ_ONLY) + set_device_ro(bdev, true); + if (nbd->flags & NBD_FLAG_SEND_TRIM) + queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, + nbd->disk->queue); + if (nbd->flags & NBD_FLAG_SEND_FLUSH) + blk_queue_flush(nbd->disk->queue, REQ_FLUSH); + else + blk_queue_flush(nbd->disk->queue, 0); + + thread = kthread_run(nbd_thread, nbd, "%s", + nbd->disk->disk_name); + if (IS_ERR(thread)) { + mutex_lock(&nbd->tx_lock); + return PTR_ERR(thread); + } + + error = nbd_do_it(nbd); + kthread_stop(thread); + + mutex_lock(&nbd->tx_lock); + if (error) + return error; + sock_shutdown(nbd, 0); + sock = nbd->sock; + nbd->sock = NULL; + nbd_clear_que(nbd); + dev_warn(disk_to_dev(nbd->disk), "queue cleared\n"); + kill_bdev(bdev); + queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, nbd->disk->queue); + set_device_ro(bdev, false); + if (sock) + sockfd_put(sock); + nbd->flags = 0; + nbd->bytesize = 0; + bdev->bd_inode->i_size = 0; + set_capacity(nbd->disk, 0); + if (max_part > 0) + ioctl_by_bdev(bdev, BLKRRPART, 0); + if (nbd->disconnect) /* user requested, ignore socket errors */ + return 0; + return nbd->harderror; + } + + case NBD_CLEAR_QUE: + /* + * This is for compatibility only. The queue is always cleared + * by NBD_DO_IT or NBD_CLEAR_SOCK. + */ + return 0; + + case NBD_PRINT_DEBUG: + dev_info(disk_to_dev(nbd->disk), + "next = %p, prev = %p, head = %p\n", + nbd->queue_head.next, nbd->queue_head.prev, + &nbd->queue_head); + return 0; + } + return -ENOTTY; +} + +static int nbd_ioctl(struct block_device *bdev, fmode_t mode, + unsigned int cmd, unsigned long arg) +{ + struct nbd_device *nbd = bdev->bd_disk->private_data; + int error; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + BUG_ON(nbd->magic != NBD_MAGIC); + + mutex_lock(&nbd->tx_lock); + error = __nbd_ioctl(bdev, nbd, cmd, arg); + mutex_unlock(&nbd->tx_lock); + + return error; +} + +static const struct block_device_operations nbd_fops = +{ + .owner = THIS_MODULE, + .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_ERR "nbd: max_part must be >= 0\n"); + return -EINVAL; + } + + part_shift = 0; + if (max_part > 0) { + part_shift = fls(max_part); + + /* + * Adjust max_part according to part_shift as it is exported + * to user space so that user can know the max number of + * partition kernel should be able to manage. + * + * Note that -1 is required because partition 0 is reserved + * for the whole disk. + */ + max_part = (1UL << part_shift) - 1; + } + + if ((1UL << part_shift) > DISK_MAX_PARTS) + return -EINVAL; + + if (nbds_max > 1UL << (MINORBITS - part_shift)) + return -EINVAL; + + nbd_dev = kcalloc(nbds_max, sizeof(*nbd_dev), GFP_KERNEL); + if (!nbd_dev) + return -ENOMEM; + + for (i = 0; i < nbds_max; i++) { + struct gendisk *disk = alloc_disk(1 << part_shift); + 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; + } + /* + * Tell the block layer that we are not a rotational device + */ + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, disk->queue); + queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, disk->queue); + disk->queue->limits.discard_granularity = 512; + disk->queue->limits.max_discard_sectors = UINT_MAX; + disk->queue->limits.discard_zeroes_data = 0; + blk_queue_max_hw_sectors(disk->queue, 65536); + disk->queue->limits.max_sectors = 256; + } + + if (register_blkdev(NBD_MAJOR, "nbd")) { + err = -EIO; + goto out; + } + + printk(KERN_INFO "nbd: registered device at major %d\n", NBD_MAJOR); + + for (i = 0; i < nbds_max; i++) { + struct gendisk *disk = nbd_dev[i].disk; + nbd_dev[i].magic = NBD_MAGIC; + 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)"); |