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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
This commit is contained in:
Linus Torvalds 2010-06-10 10:26:42 -07:00
parent e1f38e2cea 6db40cf047
commit 8fade6aff7
2 changed files with 62 additions and 30 deletions
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72
fs/block_dev.c
View File

@ -706,8 +706,13 @@ retry:
* @bdev is about to be opened exclusively. Check @bdev can be opened
* exclusively and mark that an exclusive open is in progress. Each
* successful call to this function must be matched with a call to
* either bd_claim() or bd_abort_claiming(). If this function
* succeeds, the matching bd_claim() is guaranteed to succeed.
* either bd_finish_claiming() or bd_abort_claiming() (which do not
* 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:
* Might sleep.
@ -734,6 +739,7 @@ static struct block_device *bd_start_claiming(struct block_device *bdev,
return ERR_PTR(-ENXIO);
whole = bdget_disk(disk, 0);
module_put(disk->fops->owner);
put_disk(disk);
if (!whole)
return ERR_PTR(-ENOMEM);
@ -782,15 +788,46 @@ static void bd_abort_claiming(struct block_device *whole, void *holder)
__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
* @bdev: block device to claim
* @holder: holder trying to claim @bdev
*
* Try to claim @bdev which must have been opened successfully. This
* 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.
* Try to claim @bdev which must have been opened successfully.
*
* CONTEXT:
* Might sleep.
@ -806,23 +843,10 @@ int bd_claim(struct block_device *bdev, void *holder)
might_sleep();
spin_lock(&bdev_lock);
res = bd_prepare_to_claim(bdev, whole, holder);
if (res == 0) {
/* 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;
}
if (whole->bd_claiming)
__bd_abort_claiming(whole, holder); /* releases bdev_lock */
else
spin_unlock(&bdev_lock);
if (res == 0)
__bd_claim(bdev, whole, holder);
spin_unlock(&bdev_lock);
return res;
}
@ -1476,7 +1500,7 @@ static int blkdev_open(struct inode * inode, struct file * filp)
if (whole) {
if (res == 0)
BUG_ON(bd_claim(bdev, filp) != 0);
bd_finish_claiming(bdev, whole, filp);
else
bd_abort_claiming(whole, filp);
}
@ -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))
goto out_blkdev_put;
BUG_ON(bd_claim(bdev, holder) != 0);
bd_finish_claiming(bdev, whole, holder);
return bdev;
out_blkdev_put:

20
fs/pipe.c
View File

@ -1145,13 +1145,20 @@ static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages)
* and adjust the indexes.
*/
if (pipe->nrbufs) {
const unsigned int tail = pipe->nrbufs & (pipe->buffers - 1);
const unsigned int head = pipe->nrbufs - tail;
unsigned int 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)
memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer));
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;
@ -1208,12 +1215,13 @@ long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
size = round_pipe_size(arg);
nr_pages = size >> PAGE_SHIFT;
ret = -EINVAL;
if (!nr_pages)
goto out;
if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) {
ret = -EPERM;
goto out;
} else if (nr_pages < PAGE_SIZE) {
ret = -EINVAL;
goto out;
}
ret = pipe_set_size(pipe, nr_pages);
break;