diff options
| author | Alan Jenkins | 2009-07-29 21:07:55 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki | 2009-07-29 21:07:55 +0200 |
| commit | dddac6a7b445de95515f64fdf82fe5dc36c02f26 (patch) | |
| tree | 39651610292d6b0c17f210f253a0dd16b022727d | |
| parent | ec79be26875f6c1468784876cb99192b7f41c7a5 (diff) | |
PM / Hibernate: Replace bdget call with simple atomic_inc of i_count
Create bdgrab(). This function copies an existing reference to a
block_device. It is safe to call from any context.
Hibernation code wishes to copy a reference to the active swap device.
Right now it calls bdget() under a spinlock, but this is wrong because
bdget() can sleep. It doesn't need a full bdget() because we already
hold a reference to active swap devices (and the spinlock protects
against swapoff).
Fixes http://bugzilla.kernel.org/show_bug.cgi?id=13827
Signed-off-by: Alan Jenkins <alan-jenkins@tuffmail.co.uk>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
| -rw-r--r-- | fs/block_dev.c | 10 | ||||
| -rw-r--r-- | include/linux/fs.h | 1 | ||||
| -rw-r--r-- | mm/swapfile.c | 4 |
3 files changed, 13 insertions, 2 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 3a6d4fb2a329..94dfda24c06e 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -564,6 +564,16 @@ struct block_device *bdget(dev_t dev) EXPORT_SYMBOL(bdget); +/** + * bdgrab -- Grab a reference to an already referenced block device + * @bdev: Block device to grab a reference to. + */ +struct block_device *bdgrab(struct block_device *bdev) +{ + atomic_inc(&bdev->bd_inode->i_count); + return bdev; +} + long nr_blockdev_pages(void) { struct block_device *bdev; diff --git a/include/linux/fs.h b/include/linux/fs.h index 0872372184fe..a36ffa5a77a4 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1946,6 +1946,7 @@ extern void putname(const char *name); extern int register_blkdev(unsigned int, const char *); extern void unregister_blkdev(unsigned int, const char *); extern struct block_device *bdget(dev_t); +extern struct block_device *bdgrab(struct block_device *bdev); extern void bd_set_size(struct block_device *, loff_t size); extern void bd_forget(struct inode *inode); extern void bdput(struct block_device *); diff --git a/mm/swapfile.c b/mm/swapfile.c index d1ade1a48ee7..8ffdc0d23c53 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -753,7 +753,7 @@ int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p) if (!bdev) { if (bdev_p) - *bdev_p = bdget(sis->bdev->bd_dev); + *bdev_p = bdgrab(sis->bdev); spin_unlock(&swap_lock); return i; @@ -765,7 +765,7 @@ int swap_type_of(dev_t device, sector_t offset, struct block_device **bdev_p) struct swap_extent, list); if (se->start_block == offset) { if (bdev_p) - *bdev_p = bdget(sis->bdev->bd_dev); + *bdev_p = bdgrab(sis->bdev); spin_unlock(&swap_lock); bdput(bdev); |