Commit 8fade6af authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'for-linus2' of git://git.kernel.dk/linux-2.6-block

* 'for-linus2' of git://git.kernel.dk/linux-2.6-block:
  pipe: fix check in "set size" fcntl
  pipe: fix pipe buffer resizing
  block: remove duplicate BUG_ON() in bd_finish_claiming()
  block: bd_start_claiming cleanup
  block: bd_start_claiming fix module refcount
parents e1f38e2c 6db40cf0
...@@ -706,8 +706,13 @@ static int bd_prepare_to_claim(struct block_device *bdev, ...@@ -706,8 +706,13 @@ static int bd_prepare_to_claim(struct block_device *bdev,
* @bdev is about to be opened exclusively. Check @bdev can be opened * @bdev is about to be opened exclusively. Check @bdev can be opened
* exclusively and mark that an exclusive open is in progress. Each * exclusively and mark that an exclusive open is in progress. Each
* successful call to this function must be matched with a call to * successful call to this function must be matched with a call to
* either bd_claim() or bd_abort_claiming(). If this function * either bd_finish_claiming() or bd_abort_claiming() (which do not
* succeeds, the matching bd_claim() is guaranteed to succeed. * fail).
*
* This function is used to gain exclusive access to the block device
* without actually causing other exclusive open attempts to fail. It
* should be used when the open sequence itself requires exclusive
* access but may subsequently fail.
* *
* CONTEXT: * CONTEXT:
* Might sleep. * Might sleep.
...@@ -734,6 +739,7 @@ static struct block_device *bd_start_claiming(struct block_device *bdev, ...@@ -734,6 +739,7 @@ static struct block_device *bd_start_claiming(struct block_device *bdev,
return ERR_PTR(-ENXIO); return ERR_PTR(-ENXIO);
whole = bdget_disk(disk, 0); whole = bdget_disk(disk, 0);
module_put(disk->fops->owner);
put_disk(disk); put_disk(disk);
if (!whole) if (!whole)
return ERR_PTR(-ENOMEM); return ERR_PTR(-ENOMEM);
...@@ -782,15 +788,46 @@ static void bd_abort_claiming(struct block_device *whole, void *holder) ...@@ -782,15 +788,46 @@ static void bd_abort_claiming(struct block_device *whole, void *holder)
__bd_abort_claiming(whole, holder); /* releases bdev_lock */ __bd_abort_claiming(whole, holder); /* releases bdev_lock */
} }
/* increment holders when we have a legitimate claim. requires bdev_lock */
static void __bd_claim(struct block_device *bdev, struct block_device *whole,
void *holder)
{
/* note that for a whole device bd_holders
* will be incremented twice, and bd_holder will
* be set to bd_claim before being set to holder
*/
whole->bd_holders++;
whole->bd_holder = bd_claim;
bdev->bd_holders++;
bdev->bd_holder = holder;
}
/**
* bd_finish_claiming - finish claiming a block device
* @bdev: block device of interest (passed to bd_start_claiming())
* @whole: whole block device returned by bd_start_claiming()
* @holder: holder trying to claim @bdev
*
* Finish a claiming block started by bd_start_claiming().
*
* CONTEXT:
* Grabs and releases bdev_lock.
*/
static void bd_finish_claiming(struct block_device *bdev,
struct block_device *whole, void *holder)
{
spin_lock(&bdev_lock);
BUG_ON(!bd_may_claim(bdev, whole, holder));
__bd_claim(bdev, whole, holder);
__bd_abort_claiming(whole, holder); /* not actually an abort */
}
/** /**
* bd_claim - claim a block device * bd_claim - claim a block device
* @bdev: block device to claim * @bdev: block device to claim
* @holder: holder trying to claim @bdev * @holder: holder trying to claim @bdev
* *
* Try to claim @bdev which must have been opened successfully. This * Try to claim @bdev which must have been opened successfully.
* function may be called with or without preceding
* blk_start_claiming(). In the former case, this function is always
* successful and terminates the claiming block.
* *
* CONTEXT: * CONTEXT:
* Might sleep. * Might sleep.
...@@ -806,22 +843,9 @@ int bd_claim(struct block_device *bdev, void *holder) ...@@ -806,22 +843,9 @@ int bd_claim(struct block_device *bdev, void *holder)
might_sleep(); might_sleep();
spin_lock(&bdev_lock); spin_lock(&bdev_lock);
res = bd_prepare_to_claim(bdev, whole, holder); res = bd_prepare_to_claim(bdev, whole, holder);
if (res == 0) { if (res == 0)
/* note that for a whole device bd_holders __bd_claim(bdev, whole, holder);
* will be incremented twice, and bd_holder will
* be set to bd_claim before being set to holder
*/
whole->bd_holders++;
whole->bd_holder = bd_claim;
bdev->bd_holders++;
bdev->bd_holder = holder;
}
if (whole->bd_claiming)
__bd_abort_claiming(whole, holder); /* releases bdev_lock */
else
spin_unlock(&bdev_lock); spin_unlock(&bdev_lock);
return res; return res;
...@@ -1476,7 +1500,7 @@ static int blkdev_open(struct inode * inode, struct file * filp) ...@@ -1476,7 +1500,7 @@ static int blkdev_open(struct inode * inode, struct file * filp)
if (whole) { if (whole) {
if (res == 0) if (res == 0)
BUG_ON(bd_claim(bdev, filp) != 0); bd_finish_claiming(bdev, whole, filp);
else else
bd_abort_claiming(whole, filp); bd_abort_claiming(whole, filp);
} }
...@@ -1712,7 +1736,7 @@ struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *h ...@@ -1712,7 +1736,7 @@ struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *h
if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) if ((mode & FMODE_WRITE) && bdev_read_only(bdev))
goto out_blkdev_put; goto out_blkdev_put;
BUG_ON(bd_claim(bdev, holder) != 0); bd_finish_claiming(bdev, whole, holder);
return bdev; return bdev;
out_blkdev_put: out_blkdev_put:
......
...@@ -1145,13 +1145,20 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages) ...@@ -1145,13 +1145,20 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages)
* and adjust the indexes. * and adjust the indexes.
*/ */
if (pipe->nrbufs) { if (pipe->nrbufs) {
const unsigned int tail = pipe->nrbufs & (pipe->buffers - 1); unsigned int tail;
const unsigned int head = pipe->nrbufs - tail; unsigned int head;
tail = pipe->curbuf + pipe->nrbufs;
if (tail < pipe->buffers)
tail = 0;
else
tail &= (pipe->buffers - 1);
head = pipe->nrbufs - tail;
if (head) if (head)
memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer)); memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer));
if (tail) if (tail)
memcpy(bufs + head, pipe->bufs + pipe->curbuf, tail * sizeof(struct pipe_buffer)); memcpy(bufs + head, pipe->bufs, tail * sizeof(struct pipe_buffer));
} }
pipe->curbuf = 0; pipe->curbuf = 0;
...@@ -1208,12 +1215,13 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg) ...@@ -1208,12 +1215,13 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
size = round_pipe_size(arg); size = round_pipe_size(arg);
nr_pages = size >> PAGE_SHIFT; nr_pages = size >> PAGE_SHIFT;
ret = -EINVAL;
if (!nr_pages)
goto out;
if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) { if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) {
ret = -EPERM; ret = -EPERM;
goto out; goto out;
} else if (nr_pages < PAGE_SIZE) {
ret = -EINVAL;
goto out;
} }
ret = pipe_set_size(pipe, nr_pages); ret = pipe_set_size(pipe, nr_pages);
break; break;
......
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