Patch "md/raid5: Compare apples to apples (or sectors to sectors)" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

md/raid5: Compare apples to apples (or sectors to sectors)

to the 4.4-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:
md-raid5-compare-apples-to-apples-or-sectors-to-sectors.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jes Sorensen <[email protected]>
Date: Tue, 16 Feb 2016 16:44:24 -0500
Subject: md/raid5: Compare apples to apples (or sectors to sectors)

From: Jes Sorensen <[email protected]>

commit e7597e69dec59b65c5525db1626b9d34afdfa678 upstream.

'max_discard_sectors' is in sectors, while 'stripe' is in bytes.

This fixes the problem where DISCARD would get disabled on some larger RAID5 configurations (6 or more drives in my testing), while it worked as expected with smaller configurations.

---
 drivers/md/raid5.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -7015,8 +7015,8 @@ static int run(struct mddev *mddev)
 		}
 
 		if (discard_supported &&
-		   mddev->queue->limits.max_discard_sectors >= stripe &&
-		   mddev->queue->limits.discard_granularity >= stripe)
+		    mddev->queue->limits.max_discard_sectors >= (stripe >> 9) &&
+		    mddev->queue->limits.discard_granularity >= stripe)
 			queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
 						mddev->queue);
 		else

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/md-raid5-compare-apples-to-apples-or-sectors-to-sectors.patch