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authorTejun Heo <tj@kernel.org>2014-09-08 08:03:56 +0900
committerJens Axboe <axboe@fb.com>2014-09-08 10:00:35 -0600
commitff9ea323816dc1c8ac7144afd4eab3ac97704430 (patch)
treea865fe69407f8c15d4d877defbc801aebf8d1849 /block/blk-core.c
parentf4da80727cfbc3590d95ff17ef8db96e6f1483a4 (diff)
downloadkernel-ff9ea323816dc1c8ac7144afd4eab3ac97704430.tar.gz
block, bdi: an active gendisk always has a request_queue associated with it
bdev_get_queue() returns the request_queue associated with the specified block_device. blk_get_backing_dev_info() makes use of bdev_get_queue() to determine the associated bdi given a block_device. All the callers of bdev_get_queue() including blk_get_backing_dev_info() assume that bdev_get_queue() may return NULL and implement NULL handling; however, bdev_get_queue() requires the passed in block_device is opened and attached to its gendisk. Because an active gendisk always has a valid request_queue associated with it, bdev_get_queue() can never return NULL and neither can blk_get_backing_dev_info(). Make it clear that neither of the two functions can return NULL and remove NULL handling from all the callers. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Chris Mason <clm@fb.com> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-core.c')
-rw-r--r--block/blk-core.c10
1 files changed, 3 insertions, 7 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index 93603e6ff479..817446175489 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -83,18 +83,14 @@ void blk_queue_congestion_threshold(struct request_queue *q)
* @bdev: device
*
* Locates the passed device's request queue and returns the address of its
- * backing_dev_info
- *
- * Will return NULL if the request queue cannot be located.
+ * backing_dev_info. This function can only be called if @bdev is opened
+ * and the return value is never NULL.
*/
struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
{
- struct backing_dev_info *ret = NULL;
struct request_queue *q = bdev_get_queue(bdev);
- if (q)
- ret = &q->backing_dev_info;
- return ret;
+ return &q->backing_dev_info;
}
EXPORT_SYMBOL(blk_get_backing_dev_info);