| From c8123f8c9cb517403b51aa41c3c46ff5e10b2c17 Mon Sep 17 00:00:00 2001 |
| From: Jens Axboe <axboe@fb.com> |
| Date: Wed, 12 Feb 2014 09:34:01 -0700 |
| Subject: block: add cond_resched() to potentially long running ioctl discard loop |
| |
| From: Jens Axboe <axboe@fb.com> |
| |
| 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 <axboe@fb.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| block/blk-lib.c | 8 ++++++++ |
| 1 file changed, 8 insertions(+) |
| |
| --- a/block/blk-lib.c |
| +++ b/block/blk-lib.c |
| @@ -121,6 +121,14 @@ int blkdev_issue_discard(struct block_de |
| |
| 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); |
| |
