md/raid5: round discard alignment up to power of 2.



blkdev_issue_discard currently assumes that the granularity
is a power of 2.  So in raid5, round the chosen number up to
avoid embarrassment.

Cc: Shaohua Li <shli@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>

parent 5eff3c43

drivers/md/raid5.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -5529,6 +5529,10 @@ static int run(struct mddev *mddev)
		* discard data disk but write parity disk
		*/
		stripe = stripe * PAGE_SIZE;
		/* Round up to power of 2, as discard handling
		* currently assumes that */
		while ((stripe-1) & stripe)
		stripe = (stripe \| (stripe-1)) + 1;
		mddev->queue->limits.discard_alignment = stripe;
		mddev->queue->limits.discard_granularity = stripe;
		/*