| From | Luis Henriques <> | Subject | [PATCH 3.11 100/121] block: add cond_resched() to potentially long running ioctl discard loop | Date | Fri, 21 Feb 2014 12:48:44 +0000 |
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3.11.10.5 -stable review patch. If anyone has any objections, please let me know.
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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: Luis Henriques <luis.henriques@canonical.com> --- block/blk-lib.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/block/blk-lib.c b/block/blk-lib.c index d6f50d5..9a32f58 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); -- 1.9.0
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