From 163d66d4fb1009d51027286cc4b921a5928961fc Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 12 Feb 2014 09:34:01 -0700 Subject: [PATCH] block: add cond_resched() to potentially long running ioctl discard loop commit c8123f8c9cb517403b51aa41c3c46ff5e10b2c17 upstream. 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. Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- block/blk-lib.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/block/blk-lib.c b/block/blk-lib.c index d6f50d572565..9a32f5868fb9 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -121,6 +121,14 @@ 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); -- 2.20.1