blk-mq: provide helper for setting up an SQ queue and tag set

This pattern is repeated throughout all the blk-mq conversions.
Provide a basic helper to get it done.

Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 33 insertions, 0 deletions

diff --git a/block/blk-mq.c b/block/blk-mq.c
index c2ecd64a2403..dcf10e39995a 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2507,6 +2507,39 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
 }
 EXPORT_SYMBOL(blk_mq_init_queue);
 
+/*
+ * Helper for setting up a queue with mq ops, given queue depth, and
+ * the passed in mq ops flags.
+ */
+struct request_queue *blk_mq_init_sq_queue(struct blk_mq_tag_set *set,
+                                           const struct blk_mq_ops *ops,
+                                           unsigned int queue_depth,
+                                           unsigned int set_flags)
+{
+        struct request_queue *q;
+        int ret;
+
+        memset(set, 0, sizeof(*set));
+        set->ops = ops;
+        set->nr_hw_queues = 1;
+        set->queue_depth = queue_depth;
+        set->numa_node = NUMA_NO_NODE;
+        set->flags = set_flags;
+
+        ret = blk_mq_alloc_tag_set(set);
+        if (ret)
+                return ERR_PTR(ret);
+
+        q = blk_mq_init_queue(set);
+        if (IS_ERR(q)) {
+                blk_mq_free_tag_set(set);
+                return q;
+        }
+
+        return q;
+}
+EXPORT_SYMBOL(blk_mq_init_sq_queue);
+
 static int blk_mq_hw_ctx_size(struct blk_mq_tag_set *tag_set)
 {
         int hw_ctx_size = sizeof(struct blk_mq_hw_ctx);