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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-24 05:04:00 +08:00
linux-next/drivers/block/nbd.c
Hani Benhabiles 04cfac4e40 nbd: zero from and len fields in NBD_CMD_DISCONNECT.
Len field is already set to zero, but not the from field which is sent
as 0xfffffffffffffe00.  This makes no sense, and may cause confuse
server implementations doing sanity checks (qemu-nbd is an example.)

Signed-off-by: Hani Benhabiles <hani@linux.com>
Cc: Paul Clements <paul.clements@us.sios.com>
Cc: Paul Clements <Paul.Clements@steeleye.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-06 16:08:18 -07:00

926 lines
22 KiB
C

/*
* 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/types.h>
#include <linux/nbd.h>
#define NBD_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_SET_TIMEOUT: return "set-timeout";
case NBD_SET_FLAGS: return "set-flags";
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";
case NBD_CMD_FLUSH: return "flush";
case NBD_CMD_TRIM: return "trim/discard";
}
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 *nbd, 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(&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, &current->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));
dprintk(DBG_TX, "%s: request %p: sending control (%s@%llu,%uB)\n",
nbd->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(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);
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(bvec, iter))
flags = MSG_MORE;
dprintk(DBG_TX, "%s: request %p: sending %d bytes data\n",
nbd->disk->disk_name, 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);
goto error_out;
}
}
}
return 0;
error_out:
return -EIO;
}
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))
goto out;
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);
err = -ENOENT;
out:
return ERR_PTR(err);
}
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;
}
dprintk(DBG_RX, "%s: request %p: got reply\n",
nbd->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(nbd, &bvec);
if (result <= 0) {
dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
result);
req->errors++;
return req;
}
dprintk(DBG_RX, "%s: request %p: got %d bytes data\n",
nbd->disk->disk_name, 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(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(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(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(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(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);
dprintk(DBG_BLKDEV, "%s: request %p: dequeued (flags=%x)\n",
req->rq_disk->disk_name, req, req->cmd_type);
nbd = req->rq_disk->private_data;
BUG_ON(nbd->magic != NBD_MAGIC);
if (unlikely(!nbd->sock)) {
dev_err(disk_to_dev(nbd->disk),
"Attempted send on closed socket\n");
req->errors++;
nbd_end_request(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_create(nbd_thread, nbd, "%s",
nbd->disk->disk_name);
if (IS_ERR(thread)) {
mutex_lock(&nbd->tx_lock);
return PTR_ERR(thread);
}
wake_up_process(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);
/* Anyone capable of this syscall can do *real bad* things */
dprintk(DBG_IOCTL, "%s: nbd_ioctl cmd=%s(0x%x) arg=%lu\n",
nbd->disk->disk_name, ioctl_cmd_to_ascii(cmd), cmd, arg);
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;
}
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);
/*
* 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;
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);
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);
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].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)");
#ifndef NDEBUG
module_param(debugflags, int, 0644);
MODULE_PARM_DESC(debugflags, "flags for controlling debug output");
#endif