dm: fix bug with RCU locking in dm_blk_report_zones

The dm_get_live_table() function makes RCU read lock so
dm_put_live_table() must be called even if dm_table map is not found.

Fixes: e76239a3 ("block: add a report_zones method")
Cc: stable@vger.kernel.org
Signed-off-by: Sergei Shtepa <sergei.shtepa@veeam.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm.c

@@ -476,8 +476,10 @@ static int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
 		return -EAGAIN;
 
 	map = dm_get_live_table(md, &srcu_idx);
-	if (!map)
-		return -EIO;
+	if (!map) {
+		ret = -EIO;
+		goto out;
+	}
 
 	do {
 		struct dm_target *tgt;