Commit c8123f8c authored Feb 12, 2014 by Jens Axboe

block: add cond_resched() to potentially long running ioctl discard loop



When mkfs issues a full device discard and the device only
supports discards of a smallish size, we can loop in
blkdev_issue_discard() for a long time. If preempt isn't enabled,
this can turn into a softlock situation and the kernel will
start complaining.

Add an explicit cond_resched() at the end of the loop to avoid
that.

Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>

parent abb97b8c

block/blk-lib.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -119,6 +119,14 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,

		atomic_inc(&bb.done);
		submit_bio(type, bio);

		/*
		* We can loop for a long time in here, if someone does
		* full device discards (like mkfs). Be nice and allow
		* us to schedule out to avoid softlocking if preempt
		* is disabled.
		*/
		cond_resched();
		}
		blk_finish_plug(&plug);