blk-mq: allow the driver to pass in a queue mapping

This allows drivers specify their own queue mapping by overriding the
setup-time function that builds the mq_map.  This can be used for
example to build the map based on the MSI-X vector mapping provided
by the core interrupt layer for PCI devices.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 15 insertions, 3 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 6e077a9d61a8..a3060078a8da 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2286,6 +2286,8 @@ EXPORT_SYMBOL_GPL(blk_mq_tags_cpumask);
  */
 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
 {
+	int ret;
+
 	BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
 
 	if (!set->nr_hw_queues)
@@ -2324,11 +2326,21 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
 	if (!set->tags)
 		return -ENOMEM;
 
-	set->mq_map = blk_mq_make_queue_map(set);
+	ret = -ENOMEM;
+	set->mq_map = kzalloc_node(sizeof(*set->mq_map) * nr_cpu_ids,
+			GFP_KERNEL, set->numa_node);
 	if (!set->mq_map)
 		goto out_free_tags;
 
-	if (blk_mq_alloc_rq_maps(set))
+	if (set->ops->map_queues)
+		ret = set->ops->map_queues(set);
+	else
+		ret = blk_mq_map_queues(set);
+	if (ret)
+		goto out_free_mq_map;
+
+	ret = blk_mq_alloc_rq_maps(set);
+	if (ret)
 		goto out_free_mq_map;
 
 	mutex_init(&set->tag_list_lock);
@@ -2342,7 +2354,7 @@ out_free_mq_map:
 out_free_tags:
 	kfree(set->tags);
 	set->tags = NULL;
-	return -ENOMEM;
+	return ret;
 }
 EXPORT_SYMBOL(blk_mq_alloc_tag_set);