blkcg: consolidate bio_issue_init() to be a part of core

bio_issue_init among other things initializes the timestamp for an IO.
Rather than have this logic handled by policies, this consolidates it to
be on the init paths (normal, clone, bounce clone).
Signed-off-by: Dennis Zhou <dennis@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Liu Bo <bo.liu@linux.alibaba.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/bio.c

@@ -611,6 +611,7 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
 	bio->bi_io_vec = bio_src->bi_io_vec;
 
 	bio_clone_blkcg_association(bio, bio_src);
+	blkcg_bio_issue_init(bio);
 }
 EXPORT_SYMBOL(__bio_clone_fast);
 

block/blk-iolatency.c

@@ -478,8 +478,6 @@ static void blkcg_iolatency_throttle(struct rq_qos *rqos, struct bio *bio)
 	if (!blk_iolatency_enabled(blkiolat))
 		return;
 
-	bio_issue_init(&bio->bi_issue, bio_sectors(bio));
-
 	while (blkg && blkg->parent) {
 		struct iolatency_grp *iolat = blkg_to_lat(blkg);
 		if (!iolat) {

block/blk-throttle.c

@@ -2115,13 +2115,6 @@ static inline void throtl_update_latency_buckets(struct throtl_data *td)
 }
 #endif
 
-static void blk_throtl_assoc_bio(struct bio *bio)
-{
-#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
-	bio_issue_init(&bio->bi_issue, bio_sectors(bio));
-#endif
-}
-
 bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
 		    struct bio *bio)
 {
@@ -2142,7 +2135,6 @@ bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
 
 	throtl_update_latency_buckets(td);
 
-	blk_throtl_assoc_bio(bio);
 	blk_throtl_update_idletime(tg);
 
 	sq = &tg->service_queue;

block/bounce.c

@@ -278,6 +278,7 @@ static struct bio *bounce_clone_bio(struct bio *bio_src, gfp_t gfp_mask,
 	}
 
 	bio_clone_blkcg_association(bio, bio_src);
+	blkcg_bio_issue_init(bio);
 
 	return bio;
 }

include/linux/blk-cgroup.h

@@ -800,6 +800,12 @@ static inline bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg
 				  struct bio *bio) { return false; }
 #endif
 
+
+static inline void blkcg_bio_issue_init(struct bio *bio)
+{
+	bio_issue_init(&bio->bi_issue, bio_sectors(bio));
+}
+
 static inline bool blkcg_bio_issue_check(struct request_queue *q,
 					 struct bio *bio)
 {
@@ -831,6 +837,8 @@ static inline bool blkcg_bio_issue_check(struct request_queue *q,
 		blkg_rwstat_add(&blkg->stat_ios, bio->bi_opf, 1);
 	}
 
+	blkcg_bio_issue_init(bio);
+
 	return !throtl;
 }
 
@@ -936,6 +944,7 @@ static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
 static inline void blkg_get(struct blkcg_gq *blkg) { }
 static inline void blkg_put(struct blkcg_gq *blkg) { }
 
+static inline void blkcg_bio_issue_init(struct bio *bio) { }
 static inline bool blkcg_bio_issue_check(struct request_queue *q,
 					 struct bio *bio) { return true; }