[PATCH v2 08/11] blk-mq: Add blk_mq_ops.init_request_no_hctx()

[John Garry]

Add a variant of the init_request function which does not pass a hctx_idx
arg.

This is important for shared sbitmap support, as it needs to be ensured for
introducing shared static rqs that the LLDD cannot think that requests
are associated with a specific HW queue.

Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
 block/blk-mq.c         | 15 ++++++++++-----
 include/linux/blk-mq.h |  7 +++++++
 2 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index f14cc2705f9b..4d6723cfa582 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2427,13 +2427,15 @@ struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
 static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
 			       unsigned int hctx_idx, int node)
 {
-	int ret;
+	int ret = 0;
 
-	if (set->ops->init_request) {
+	if (set->ops->init_request)
 		ret = set->ops->init_request(set, rq, hctx_idx, node);
-		if (ret)
-			return ret;
-	}
+	else if (set->ops->init_request_no_hctx)
+		ret = set->ops->init_request_no_hctx(set, rq, node);
+
+	if (ret)
+		return ret;
 
 	WRITE_ONCE(rq->state, MQ_RQ_IDLE);
 	return 0;
@@ -3487,6 +3489,9 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
 	if (!set->ops->get_budget ^ !set->ops->put_budget)
 		return -EINVAL;
 
+	if (set->ops->init_request && set->ops->init_request_no_hctx)
+		return -EINVAL;
+
 	if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
 		pr_info("blk-mq: reduced tag depth to %u\n",
 			BLK_MQ_MAX_DEPTH);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 22215db36122..c838b24944c2 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -357,6 +357,13 @@ struct blk_mq_ops {
 	 */
 	int (*init_request)(struct blk_mq_tag_set *set, struct request *,
 			    unsigned int, unsigned int);
+
+	/**
+	 * @init_request: Same as init_request, except no hw queue index is passed
+	 */
+	int (*init_request_no_hctx)(struct blk_mq_tag_set *set, struct request *,
+				    unsigned int);
+
 	/**
 	 * @exit_request: Ditto for exit/teardown.
 	 */
-- 
2.26.2