dm: remove unnecessary wrapper around blk_lld_busy

There is no need for DM to export a wrapper around the already exported
blk_lld_busy().
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-mpath.c

@@ -1627,7 +1627,7 @@ static int __pgpath_busy(struct pgpath *pgpath)
 {
 	struct request_queue *q = bdev_get_queue(pgpath->path.dev->bdev);
 
-	return dm_underlying_device_busy(q);
+	return blk_lld_busy(q);
 }
 
 /*

drivers/md/dm.c

@@ -2006,12 +2006,6 @@ static void dm_request_fn(struct request_queue *q)
 	dm_put_live_table(md, srcu_idx);
 }
 
-int dm_underlying_device_busy(struct request_queue *q)
-{
-	return blk_lld_busy(q);
-}
-EXPORT_SYMBOL_GPL(dm_underlying_device_busy);
-
 static int dm_lld_busy(struct request_queue *q)
 {
 	int r;

include/linux/device-mapper.h

@@ -605,9 +605,4 @@ static inline unsigned long to_bytes(sector_t n)
 	return (n << SECTOR_SHIFT);
 }
 
-/*-----------------------------------------------------------------
- * Helper for block layer and dm core operations
- *---------------------------------------------------------------*/
-int dm_underlying_device_busy(struct request_queue *q);
-
 #endif	/* _LINUX_DEVICE_MAPPER_H */