[PATCH v2 2/5] blk-mq: remove RQF_MQ_INFLIGHT

chengming.zhou
2023-09-13T15:17:22Z

From: Chengming Zhou <zhouchengming@bytedance.com>

Since the previous patch change to only account active requests when
we really allocate the driver tag, the RQF_MQ_INFLIGHT can be removed
and no double account problem.

1. none elevator: flush request will use the first pending request's
driver tag, won't double account.

2. other elevator: flush request will be accounted when allocate driver
tag when issue, and will be unaccounted when it put the driver tag.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
block/blk-flush.c | 11 ++---------
block/blk-mq-debugfs.c | 1 -
block/blk-mq.c | 4 ----
include/linux/blk-mq.h | 2 --
4 files changed, 2 insertions(+), 16 deletions(-)

diff --git a/block/blk-flush.c b/block/blk-flush.c
index e73dc22d05c1..3f4d41952ef2 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -323,16 +323,9 @@ static void blk_kick_flush(struct request_queue *q, struct blk_flush_queue *fq,
flush_rq->mq_ctx = first_rq->mq_ctx;
flush_rq->mq_hctx = first_rq->mq_hctx;

- if (!q->elevator) {
+ if (!q->elevator)
flush_rq->tag = first_rq->tag;
-
- /*
- * We borrow data request's driver tag, so have to mark
- * this flush request as INFLIGHT for avoiding double
- * account of this driver tag
- */
- flush_rq->rq_flags |= RQF_MQ_INFLIGHT;
- } else
+ else
flush_rq->internal_tag = first_rq->internal_tag;

flush_rq->cmd_flags = REQ_OP_FLUSH | REQ_PREFLUSH;
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index c3b5930106b2..5cbeb9344f2f 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -246,7 +246,6 @@ static const char *const rqf_name[] = {
RQF_NAME(STARTED),
RQF_NAME(FLUSH_SEQ),
RQF_NAME(MIXED_MERGE),
- RQF_NAME(MQ_INFLIGHT),
RQF_NAME(DONTPREP),
RQF_NAME(SCHED_TAGS),
RQF_NAME(USE_SCHED),
diff --git a/block/blk-mq.c b/block/blk-mq.c
index e776388decc3..c209a7dddee3 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1066,10 +1066,6 @@ static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx,
{
struct request_queue *q = hctx->queue;

- /*
- * All requests should have been marked as RQF_MQ_INFLIGHT, so
- * update hctx->nr_active in batch
- */
blk_mq_sub_active_requests(hctx, nr_tags);

blk_mq_put_tags(hctx->tags, tag_array, nr_tags);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 958ed7e89b30..1ab3081c82ed 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -32,8 +32,6 @@ typedef __u32 __bitwise req_flags_t;
#define RQF_FLUSH_SEQ ((__force req_flags_t)(1 << 4))
/* merge of different types, fail separately */
#define RQF_MIXED_MERGE ((__force req_flags_t)(1 << 5))
-/* track inflight for MQ */
-#define RQF_MQ_INFLIGHT ((__force req_flags_t)(1 << 6))
/* don't call prep for this one */
#define RQF_DONTPREP ((__force req_flags_t)(1 << 7))
/* use hctx->sched_tags */
--
2.40.1