MD RAID10: Export md_raid10_congested

md/raid10: Export is_congested test.

In similar fashion to commits
	11d8a6e3719519fbc0e2c9d61b6fa931b84bf813
	1ed7242e591af7e233234d483f12d33818b189d9
we export the RAID10 congestion checking function so that dm-raid.c can
make use of it and make use of the personality.  The 'queue' and 'gendisk'
structures will not be available to the MD code when device-mapper sets
up the device, so we conditionalize access to these fields also.

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

2 files changed, 37 insertions, 22 deletions

diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index e77acf024055..e2549deab7c3 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -853,9 +853,8 @@ retry:
         return rdev;
 }
 
-static int raid10_congested(void *data, int bits)
+int md_raid10_congested(struct mddev *mddev, int bits)
 {
-        struct mddev *mddev = data;
         struct r10conf *conf = mddev->private;
         int i, ret = 0;
 
@@ -863,8 +862,6 @@ static int raid10_congested(void *data, int bits)
             conf->pending_count >= max_queued_requests)
                 return 1;
 
-        if (mddev_congested(mddev, bits))
-                return 1;
         rcu_read_lock();
         for (i = 0;
              (i < conf->geo.raid_disks || i < conf->prev.raid_disks)
@@ -880,6 +877,15 @@ static int raid10_congested(void *data, int bits)
         rcu_read_unlock();
         return ret;
 }
+EXPORT_SYMBOL_GPL(md_raid10_congested);
+
+static int raid10_congested(void *data, int bits)
+{
+        struct mddev *mddev = data;
+
+        return mddev_congested(mddev, bits) ||
+                md_raid10_congested(mddev, bits);
+}
 
 static void flush_pending_writes(struct r10conf *conf)
 {
@@ -3486,12 +3492,14 @@ static int run(struct mddev *mddev)
         conf->thread = NULL;
 
         chunk_size = mddev->chunk_sectors << 9;
-        blk_queue_io_min(mddev->queue, chunk_size);
-        if (conf->geo.raid_disks % conf->geo.near_copies)
-                blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);
-        else
-                blk_queue_io_opt(mddev->queue, chunk_size *
-                                 (conf->geo.raid_disks / conf->geo.near_copies));
+        if (mddev->queue) {
+                blk_queue_io_min(mddev->queue, chunk_size);
+                if (conf->geo.raid_disks % conf->geo.near_copies)
+                        blk_queue_io_opt(mddev->queue, chunk_size * conf->geo.raid_disks);
+                else
+                        blk_queue_io_opt(mddev->queue, chunk_size *
+                                         (conf->geo.raid_disks / conf->geo.near_copies));
+        }
 
         rdev_for_each(rdev, mddev) {
                 long long diff;
@@ -3525,8 +3533,9 @@ static int run(struct mddev *mddev)
                 if (first || diff < min_offset_diff)
                         min_offset_diff = diff;
 
-                disk_stack_limits(mddev->gendisk, rdev->bdev,
-                                  rdev->data_offset << 9);
+                if (mddev->gendisk)
+                        disk_stack_limits(mddev->gendisk, rdev->bdev,
+                                          rdev->data_offset << 9);
 
                 disk->head_position = 0;
         }
@@ -3589,22 +3598,22 @@ static int run(struct mddev *mddev)
         md_set_array_sectors(mddev, size);
         mddev->resync_max_sectors = size;
 
-        mddev->queue->backing_dev_info.congested_fn = raid10_congested;
-        mddev->queue->backing_dev_info.congested_data = mddev;
-
-        /* Calculate max read-ahead size.
-         * We need to readahead at least twice a whole stripe....
-         * maybe...
-         */
-        {
+        if (mddev->queue) {
                 int stripe = conf->geo.raid_disks *
                         ((mddev->chunk_sectors << 9) / PAGE_SIZE);
+                mddev->queue->backing_dev_info.congested_fn = raid10_congested;
+                mddev->queue->backing_dev_info.congested_data = mddev;
+
+                /* Calculate max read-ahead size.
+                 * We need to readahead at least twice a whole stripe....
+                 * maybe...
+                 */
                 stripe /= conf->geo.near_copies;
                 if (mddev->queue->backing_dev_info.ra_pages < 2 * stripe)
                         mddev->queue->backing_dev_info.ra_pages = 2 * stripe;
+                blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
         }
 
-        blk_queue_merge_bvec(mddev->queue, raid10_mergeable_bvec);
 
         if (md_integrity_register(mddev))
                 goto out_free_conf;
@@ -3655,7 +3664,10 @@ static int stop(struct mddev *mddev)
         lower_barrier(conf);
 
         md_unregister_thread(&mddev->thread);
-        blk_sync_queue(mddev->queue); /* the unplug fn references 'conf'*/
+        if (mddev->queue)
+                /* the unplug fn references 'conf'*/
+                blk_sync_queue(mddev->queue);
+
         if (conf->r10bio_pool)
                 mempool_destroy(conf->r10bio_pool);
         kfree(conf->mirrors);
diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h
index b0a435869dca..007c2c68dd83 100644
--- a/drivers/md/raid10.h
+++ b/drivers/md/raid10.h
@@ -145,4 +145,7 @@ enum r10bio_state {
  */
         R10BIO_Previous,
 };
+
+extern int md_raid10_congested(struct mddev *mddev, int bits);
+
 #endif