This is a note to let you know that I've just added the patch titled
block: add cond_resched() to potentially long running ioctl discard loop
to the 3.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
block-add-cond_resched-to-potentially-long-running-ioctl-discard-loop.patch
and it can be found in the queue-3.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c8123f8c9cb517403b51aa41c3c46ff5e10b2c17 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@xxxxxx>
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@xxxxxx>
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@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-lib.c | 8 ++++++++
1 file changed, 8 insertions(+)
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -119,6 +119,14 @@ 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);
Patches currently in stable-queue which might be from axboe@xxxxxx are
queue-3.13/block-fix-nr_vecs-for-inline-integrity-vectors.patch
queue-3.13/block-add-cond_resched-to-potentially-long-running-ioctl-discard-loop.patch
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