dm table: add dm_table_run_md_queue_async

Introduce dm_table_run_md_queue_async() to run the request_queue of the
mapped_device associated with a request-based DM table.

Also add dm_md_get_queue() wrapper to extract the request_queue from a
mapped_device.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>

3 files changed, 25 insertions, 0 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 2ae35b2f80fd..50601ec7017a 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1618,6 +1618,25 @@ struct mapped_device *dm_table_get_md(struct dm_table *t)
 }
 EXPORT_SYMBOL(dm_table_get_md);
 
+void dm_table_run_md_queue_async(struct dm_table *t)
+{
+        struct mapped_device *md;
+        struct request_queue *queue;
+        unsigned long flags;
+
+        if (!dm_table_request_based(t))
+                return;
+
+        md = dm_table_get_md(t);
+        queue = dm_get_md_queue(md);
+        if (queue) {
+                spin_lock_irqsave(queue->queue_lock, flags);
+                blk_run_queue_async(queue);
+                spin_unlock_irqrestore(queue->queue_lock, flags);
+        }
+}
+EXPORT_SYMBOL(dm_table_run_md_queue_async);
+
 static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
                                   sector_t start, sector_t len, void *data)
 {
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 6382213dbd88..455e64916498 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -468,6 +468,11 @@ sector_t dm_get_size(struct mapped_device *md)
         return get_capacity(md->disk);
 }
 
+struct request_queue *dm_get_md_queue(struct mapped_device *md)
+{
+        return md->queue;
+}
+
 struct dm_stats *dm_get_stats(struct mapped_device *md)
 {
         return &md->stats;
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index 88cc58c5871a..ed76126aac54 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -188,6 +188,7 @@ int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only
 int dm_cancel_deferred_remove(struct mapped_device *md);
 int dm_request_based(struct mapped_device *md);
 sector_t dm_get_size(struct mapped_device *md);
+struct request_queue *dm_get_md_queue(struct mapped_device *md);
 struct dm_stats *dm_get_stats(struct mapped_device *md);
 
 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,