[3.19.y-ckt stable] Patch "md/raid0: apply base queue limits *before* disk_stack_limits" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    md/raid0: apply base queue limits *before* disk_stack_limits

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt10.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 79fb14e6e4d9a404de8d58e3917f3f3b8e6cfc1c Mon Sep 17 00:00:00 2001
From: NeilBrown <neilb at suse.com>
Date: Thu, 24 Sep 2015 15:47:47 +1000
Subject: md/raid0: apply base queue limits *before* disk_stack_limits

commit 66eefe5de11db1e0d8f2edc3880d50e7c36a9d43 upstream.

Calling e.g. blk_queue_max_hw_sectors() after calls to
disk_stack_limits() discards the settings determined by
disk_stack_limits().
So we need to make those calls first.

Fixes: 199dc6ed5179 ("md/raid0: update queue parameter in a safer location.")
Reported-by: Jes Sorensen <Jes.Sorensen at redhat.com>
Signed-off-by: NeilBrown <neilb at suse.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/md/raid0.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 910edd2..ff028ae 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -438,12 +438,6 @@ static int raid0_run(struct mddev *mddev)
 		struct md_rdev *rdev;
 		bool discard_supported = false;

-		rdev_for_each(rdev, mddev) {
-			disk_stack_limits(mddev->gendisk, rdev->bdev,
-					  rdev->data_offset << 9);
-			if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
-				discard_supported = true;
-		}
 		blk_queue_max_hw_sectors(mddev->queue, mddev->chunk_sectors);
 		blk_queue_max_write_same_sectors(mddev->queue, mddev->chunk_sectors);
 		blk_queue_max_discard_sectors(mddev->queue, mddev->chunk_sectors);
@@ -452,6 +446,12 @@ static int raid0_run(struct mddev *mddev)
 		blk_queue_io_opt(mddev->queue,
 				 (mddev->chunk_sectors << 9) * mddev->raid_disks);

+		rdev_for_each(rdev, mddev) {
+			disk_stack_limits(mddev->gendisk, rdev->bdev,
+					  rdev->data_offset << 9);
+			if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
+				discard_supported = true;
+		}
 		if (!discard_supported)
 			queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
 		else
--
1.9.1