From 4ac6875eeb97a49bad7bc8d56b5ec935904fc6e7 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Mon, 19 Nov 2012 13:11:26 +1100 Subject: [PATCH] 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 Signed-off-by: NeilBrown --- drivers/md/raid5.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index c5439dce029..baea94f0670 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -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; /* -- 2.20.1