dm table: simplify dm_table_determine_type()

[karo-tx-linux.git] / drivers / md / dm-table.c

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index c4b53b332607bec3f303671da385656713498e04..0a427de23ed2c6a01fa183738705b8c8f6e3e099 100644 (file)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -871,7 +871,7 @@ static int dm_table_determine_type(struct dm_table *t)
 {
        unsigned i;
        unsigned bio_based = 0, request_based = 0, hybrid = 0;
-       bool verify_blk_mq = false;
+       unsigned sq_count = 0, mq_count = 0;
        struct dm_target *tgt;
        struct dm_dev_internal *dd;
        struct list_head *devices = dm_table_get_devices(t);
@@ -924,12 +924,6 @@ static int dm_table_determine_type(struct dm_table *t)
 
        BUG_ON(!request_based); /* No targets in this table */
 
-       if (list_empty(devices) && __table_type_request_based(live_md_type)) {
-               /* inherit live MD type */
-               t->type = live_md_type;
-               return 0;
-       }
-
        /*
         * The only way to establish DM_TYPE_MQ_REQUEST_BASED is by
         * having a compatible target use dm_table_set_type.
@@ -948,6 +942,19 @@ verify_rq_based:
                return -EINVAL;
        }
 
+       if (list_empty(devices)) {
+               int srcu_idx;
+               struct dm_table *live_table = dm_get_live_table(t->md, &srcu_idx);
+
+               /* inherit live table's type and all_blk_mq */
+               if (live_table) {
+                       t->type = live_table->type;
+                       t->all_blk_mq = live_table->all_blk_mq;
+               }
+               dm_put_live_table(t->md, srcu_idx);
+               return 0;
+       }
+
        /* Non-request-stackable devices can't be used for request-based dm */
        list_for_each_entry(dd, devices, list) {
                struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
@@ -959,19 +966,19 @@ verify_rq_based:
                }
 
                if (q->mq_ops)
-                       verify_blk_mq = true;
+                       mq_count++;
+               else
+                       sq_count++;
        }
+       if (sq_count && mq_count) {
+               DMERR("table load rejected: not all devices are blk-mq request-stackable");
+               return -EINVAL;
+       }
+       t->all_blk_mq = mq_count > 0;
 
-       if (verify_blk_mq) {
-               /* verify _all_ devices in the table are blk-mq devices */
-               list_for_each_entry(dd, devices, list)
-                       if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
-                               DMERR("table load rejected: not all devices"
-                                     " are blk-mq request-stackable");
-                               return -EINVAL;
-                       }
-
-               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;