[PATCH 04/10] block/rq_qos: add rq_qos_merge()

[Tejun Heo]

Add a merge hook for rq_qos.  This will be used by io.weight.

Signed-off-by: Tejun Heo <t...@kernel.org>
---
 block/blk-core.c   | 4 ++++
 block/blk-rq-qos.c | 9 +++++++++
 block/blk-rq-qos.h | 9 +++++++++
 3 files changed, 22 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index 77807a5d7f9e..875e8d105067 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -604,6 +604,7 @@ bool bio_attempt_back_merge(struct request *req, struct bio 
*bio,
                return false;
 
        trace_block_bio_backmerge(req->q, req, bio);
+       rq_qos_merge(req->q, req, bio);
 
        if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
                blk_rq_set_mixed_merge(req);
@@ -625,6 +626,7 @@ bool bio_attempt_front_merge(struct request *req, struct 
bio *bio,
                return false;
 
        trace_block_bio_frontmerge(req->q, req, bio);
+       rq_qos_merge(req->q, req, bio);
 
        if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
                blk_rq_set_mixed_merge(req);
@@ -650,6 +652,8 @@ bool bio_attempt_discard_merge(struct request_queue *q, 
struct request *req,
            blk_rq_get_max_sectors(req, blk_rq_pos(req)))
                goto no_merge;
 
+       rq_qos_merge(q, req, bio);
+
        req->biotail->bi_next = bio;
        req->biotail = bio;
        req->__data_len += bio->bi_iter.bi_size;
diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c
index 3954c0dc1443..f4eea78f5cc1 100644
--- a/block/blk-rq-qos.c
+++ b/block/blk-rq-qos.c
@@ -83,6 +83,15 @@ void __rq_qos_track(struct rq_qos *rqos, struct request *rq, 
struct bio *bio)
        } while (rqos);
 }
 
+void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio)
+{
+       do {
+               if (rqos->ops->merge)
+                       rqos->ops->merge(rqos, rq, bio);
+               rqos = rqos->next;
+       } while (rqos);
+}
+
 void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio)
 {
        do {
diff --git a/block/blk-rq-qos.h b/block/blk-rq-qos.h
index 2300e038b9fa..8e426a8505b6 100644
--- a/block/blk-rq-qos.h
+++ b/block/blk-rq-qos.h
@@ -35,6 +35,7 @@ struct rq_qos {
 struct rq_qos_ops {
        void (*throttle)(struct rq_qos *, struct bio *);
        void (*track)(struct rq_qos *, struct request *, struct bio *);
+       void (*merge)(struct rq_qos *, struct request *, struct bio *);
        void (*issue)(struct rq_qos *, struct request *);
        void (*requeue)(struct rq_qos *, struct request *);
        void (*done)(struct rq_qos *, struct request *);
@@ -135,6 +136,7 @@ void __rq_qos_issue(struct rq_qos *rqos, struct request 
*rq);
 void __rq_qos_requeue(struct rq_qos *rqos, struct request *rq);
 void __rq_qos_throttle(struct rq_qos *rqos, struct bio *bio);
 void __rq_qos_track(struct rq_qos *rqos, struct request *rq, struct bio *bio);
+void __rq_qos_merge(struct rq_qos *rqos, struct request *rq, struct bio *bio);
 void __rq_qos_done_bio(struct rq_qos *rqos, struct bio *bio);
 
 static inline void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
@@ -185,6 +187,13 @@ static inline void rq_qos_track(struct request_queue *q, 
struct request *rq,
                __rq_qos_track(q->rq_qos, rq, bio);
 }
 
+static inline void rq_qos_merge(struct request_queue *q, struct request *rq,
+                               struct bio *bio)
+{
+       if (q->rq_qos)
+               __rq_qos_merge(q->rq_qos, rq, bio);
+}
+
 void rq_qos_exit(struct request_queue *);
 
 #endif
-- 
2.17.1