MD RAID10: Fix oops when creating RAID10 arrays via dm-raid.c

Commit 2863b9eb didn't take into account the changes to add TRIM support to
RAID10 (commit 532a2a3fb).  That is, when using dm-raid.c to create the
RAID10 arrays, there is no mddev->gendisk or mddev->queue.  The code added
to support TRIM simply assumes that mddev->queue is available without
checking.  The result is an oops any time dm-raid.c attempts to create a
RAID10 device.

Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 9 insertions, 6 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 906ccbd0f7dc..d1295aff4173 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1783,7 +1783,7 @@ static int raid10_add_disk(struct mddev *mddev, struct md_rdev *rdev)
                 clear_bit(Unmerged, &rdev->flags);
         }
         md_integrity_add_rdev(rdev, mddev);
-        if (blk_queue_discard(bdev_get_queue(rdev->bdev)))
+        if (mddev->queue && blk_queue_discard(bdev_get_queue(rdev->bdev)))
                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
 
         print_conf(conf);
@@ -3613,11 +3613,14 @@ static int run(struct mddev *mddev)
                         discard_supported = true;
         }
 
-        if (discard_supported)
-                queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
-        else
-                queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
-
+        if (mddev->queue) {
+                if (discard_supported)
+                        queue_flag_set_unlocked(QUEUE_FLAG_DISCARD,
+                                                mddev->queue);
+                else
+                        queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD,
+                                                  mddev->queue);
+        }
         /* need to check that every block has at least one working mirror */
         if (!enough(conf, -1)) {
                 printk(KERN_ERR "md/raid10:%s: not enough operational mirrors.\n",