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

John Garry
2021-08-09T14:38:14Z

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@huawei.com>
---
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