md raid0: access mddev->queue (request queue member) conditionally because it is not set when accessed from dm-raid

The patch makes 3 references to mddev->queue in the raid0 personality
conditional in order to allow for it to be accessed from dm-raid.
Mandatory, because md instances underneath dm-raid don't manage
a request queue of their own which'd lead to oopses without the patch.

Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Tested-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 27 insertions, 21 deletions

diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 3b5d7f704aa3..2cb59a641cd2 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -271,14 +271,16 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf)
                 goto abort;
         }
 
-        blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
-        blk_queue_io_opt(mddev->queue,
-                         (mddev->chunk_sectors << 9) * mddev->raid_disks);
-
-        if (!discard_supported)
-                queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
-        else
-                queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
+        if (mddev->queue) {
+                blk_queue_io_min(mddev->queue, mddev->chunk_sectors << 9);
+                blk_queue_io_opt(mddev->queue,
+                                 (mddev->chunk_sectors << 9) * mddev->raid_disks);
+
+                if (!discard_supported)
+                        queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
+                else
+                        queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, mddev->queue);
+        }
 
         pr_debug("md/raid0:%s: done.\n", mdname(mddev));
         *private_conf = conf;
@@ -429,9 +431,12 @@ static int raid0_run(struct mddev *mddev)
         }
         if (md_check_no_bitmap(mddev))
                 return -EINVAL;
-        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);
+
+        if (mddev->queue) {
+                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);
+        }
 
         /* if private is not null, we are here after takeover */
         if (mddev->private == NULL) {
@@ -448,16 +453,17 @@ static int raid0_run(struct mddev *mddev)
         printk(KERN_INFO "md/raid0:%s: md_size is %llu sectors.\n",
                mdname(mddev),
                (unsigned long long)mddev->array_sectors);
-        /* calculate the max read-ahead size.
-         * For read-ahead of large files to be effective, we need to
-         * readahead at least twice a whole stripe. i.e. number of devices
-         * multiplied by chunk size times 2.
-         * If an individual device has an ra_pages greater than the
-         * chunk size, then we will not drive that device as hard as it
-         * wants.  We consider this a configuration error: a larger
-         * chunksize should be used in that case.
-         */
-        {
+
+        if (mddev->queue) {
+                /* calculate the max read-ahead size.
+                 * For read-ahead of large files to be effective, we need to
+                 * readahead at least twice a whole stripe. i.e. number of devices
+                 * multiplied by chunk size times 2.
+                 * If an individual device has an ra_pages greater than the
+                 * chunk size, then we will not drive that device as hard as it
+                 * wants.  We consider this a configuration error: a larger
+                 * chunksize should be used in that case.
+                 */
                 int stripe = mddev->raid_disks *
                         (mddev->chunk_sectors << 9) / PAGE_SIZE;
                 if (mddev->queue->backing_dev_info.ra_pages < 2* stripe)