dm: do not set QUEUE_ORDERED_DRAIN if request based

Request-based dm doesn't have barrier support yet.
So we need to set QUEUE_ORDERED_DRAIN only for bio-based dm.
Since the device type is decided at the first table loading time,
the flag set is deferred until then.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

3 files changed, 16 insertions, 1 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index aaeb82ed285..4899ebe767c 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -830,6 +830,11 @@ unsigned dm_table_get_type(struct dm_table *t)
         return t->type;
 }
 
+bool dm_table_bio_based(struct dm_table *t)
+{
+        return dm_table_get_type(t) == DM_TYPE_BIO_BASED;
+}
+
 bool dm_table_request_based(struct dm_table *t)
 {
         return dm_table_get_type(t) == DM_TYPE_REQUEST_BASED;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 5a843c1f4d6..00c76886081 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1768,7 +1768,6 @@ static struct mapped_device *alloc_dev(int minor)
         md->queue->backing_dev_info.congested_fn = dm_any_congested;
         md->queue->backing_dev_info.congested_data = md;
         blk_queue_make_request(md->queue, dm_request);
-        blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN, NULL);
         blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
         md->queue->unplug_fn = dm_unplug_all;
         blk_queue_merge_bvec(md->queue, dm_merge_bvec);
@@ -2201,6 +2200,16 @@ int dm_swap_table(struct mapped_device *md, struct dm_table *table)
                 goto out;
         }
 
+        /*
+         * It is enought that blk_queue_ordered() is called only once when
+         * the first bio-based table is bound.
+         *
+         * This setting should be moved to alloc_dev() when request-based dm
+         * supports barrier.
+         */
+        if (!md->map && dm_table_bio_based(table))
+                blk_queue_ordered(md->queue, QUEUE_ORDERED_DRAIN, NULL);
+
         __unbind(md);
         r = __bind(md, table, &limits);
 
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index a7663eba17e..23278ae80f0 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -61,6 +61,7 @@ int dm_table_any_congested(struct dm_table *t, int bdi_bits);
 int dm_table_any_busy_target(struct dm_table *t);
 int dm_table_set_type(struct dm_table *t);
 unsigned dm_table_get_type(struct dm_table *t);
+bool dm_table_bio_based(struct dm_table *t);
 bool dm_table_request_based(struct dm_table *t);
 int dm_table_alloc_md_mempools(struct dm_table *t);
 void dm_table_free_md_mempools(struct dm_table *t);