--- /dev/null
+/*
+ * 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 <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_all(req, error);
+ 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 = blk_rq_bytes(req);
+
+ request.magic = htonl(NBD_REQUEST_MAGIC);
+ request.type = htonl(nbd_cmd(req));
+ request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
+ request.len = htonl(size);
+ memcpy(request.handle, &req, sizeof(req));
+
+ dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n",
+ lo->disk->disk_name, req,
+ nbdcmd_to_ascii(nbd_cmd(req)),
+ (unsigned long long)blk_rq_pos(req) << 9,
+ blk_rq_bytes(req));
+ 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 -EIO;
+}
+
+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 (req->cmd_type != REQ_TYPE_FS)
+ 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);
+ goto error_out;
+ }
+
+ 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 = blk_fetch_request(q)) != NULL) {
+ struct nbd_device *lo;
+
+ 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);
+ }
+}
+
+/* Must be called with tx_lock held */
+
+static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *lo,
+ unsigned int cmd, unsigned long arg)
+{
+ switch (cmd) {
+ case NBD_DISCONNECT: {
+ struct request sreq;
+
+ 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;
+ if (!lo->sock)
+ return -EINVAL;
+ nbd_send_req(lo, &sreq);
+ return 0;
+ }
+
+ case NBD_CLEAR_SOCK: {
+ struct file *file;
+
+ lo->sock = NULL;
+ file = lo->file;
+ lo->file = NULL;
+ nbd_clear_que(lo);
+ BUG_ON(!list_empty(&lo->queue_head));
+ if (file)
+ fput(file);
+ return 0;
+ }
+
+ case NBD_SET_SOCK: {
+ struct file *file;
+ if (lo->file)
+ return -EBUSY;
+ 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;
+ return 0;
+ } else {
+ fput(file);
+ }
+ }
+ return -EINVAL;
+ }
+
+ 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: {
+ struct task_struct *thread;
+ struct file *file;
+ int error;
+
+ if (lo->pid)
+ return -EBUSY;
+ if (!lo->file)
+ return -EINVAL;
+
+ mutex_unlock(&lo->tx_lock);
+
+ thread = kthread_create(nbd_thread, lo, lo->disk->disk_name);
+ if (IS_ERR(thread)) {
+ mutex_lock(&lo->tx_lock);
+ return PTR_ERR(thread);
+ }
+ wake_up_process(thread);
+ error = nbd_do_it(lo);
+ kthread_stop(thread);
+
+ mutex_lock(&lo->tx_lock);
+ if (error)
+ return error;
+ sock_shutdown(lo, 0);
+ 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 -ENOTTY;
+}
+
+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;
+ int error;
+
+ 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);
+
+ mutex_lock(&lo->tx_lock);
+ error = __nbd_ioctl(bdev, lo, cmd, arg);
+ mutex_unlock(&lo->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_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);
+ 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);
+ }
+
+ 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
projects / nbd-module.git / commitdiff