| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.12 66/82] block: add cond_resched() to potentially long running ioctl discard loop | Date | Thu, 20 Feb 2014 15:52:49 -0800 |
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3.12-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: 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);
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