dm table: an 'all_blk_mq' table must be loaded for a blk-mq DM device

commit 301fc3f5efb98633115bd887655b19f42c6dfaa8 upstream.

When dm_table_set_type() is used by a target to establish a DM table's
type (e.g. DM_TYPE_MQ_REQUEST_BASED in the case of DM multipath) the
DM core must go on to verify that the devices in the table are
compatible with the established type.

Fixes: e83068a5 ("dm mpath: add optional "queue_mode" feature")
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 53b817b29134..5ac239d0f787 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -981,6 +981,11 @@ verify_rq_based:
                 t->all_blk_mq = true;
         }
 
+        if (t->type == DM_TYPE_MQ_REQUEST_BASED && !t->all_blk_mq) {
+                DMERR("table load rejected: all devices are not blk-mq request-stackable");
+                return -EINVAL;
+        }
+
         return 0;
 }