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author | Baolin Wang <baolin.wang@linux.alibaba.com> | 2020-08-28 10:52:56 +0800 |
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committer | Jens Axboe <axboe@kernel.dk> | 2020-09-01 16:49:26 -0600 |
commit | 7d7ca7c5269becab86c9f595309c8e90ce268967 (patch) | |
tree | b19837e1b64f7d96bced5a4d6994b185d7e0f81d | |
parent | bdc6a287bc98e8f32bf52c9cb2d1bdf75975f5a0 (diff) | |
download | linux-7d7ca7c5269becab86c9f595309c8e90ce268967.tar.gz linux-7d7ca7c5269becab86c9f595309c8e90ce268967.tar.bz2 linux-7d7ca7c5269becab86c9f595309c8e90ce268967.zip |
block: Add a new helper to attempt to merge a bio
There are lots of duplicated code when trying to merge a bio from
plug list and sw queue, we can introduce a new helper to attempt
to merge a bio, which can simplify the blk_bio_list_merge()
and blk_attempt_plug_merge().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r-- | block/blk-merge.c | 104 | ||||
-rw-r--r-- | block/blk-mq-sched.c | 6 | ||||
-rw-r--r-- | block/blk.h | 21 |
3 files changed, 71 insertions, 60 deletions
diff --git a/block/blk-merge.c b/block/blk-merge.c index b09e9fc44236..80c974484a3f 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -907,13 +907,14 @@ static void blk_account_io_merge_bio(struct request *req) part_stat_unlock(); } -bool bio_attempt_back_merge(struct request *req, struct bio *bio, - unsigned int nr_segs) +enum bio_merge_status bio_attempt_back_merge(struct request *req, + struct bio *bio, + unsigned int nr_segs) { const int ff = bio->bi_opf & REQ_FAILFAST_MASK; if (!ll_back_merge_fn(req, bio, nr_segs)) - return false; + return BIO_MERGE_FAILED; trace_block_bio_backmerge(req->q, req, bio); rq_qos_merge(req->q, req, bio); @@ -928,16 +929,17 @@ bool bio_attempt_back_merge(struct request *req, struct bio *bio, bio_crypt_free_ctx(bio); blk_account_io_merge_bio(req); - return true; + return BIO_MERGE_OK; } -bool bio_attempt_front_merge(struct request *req, struct bio *bio, - unsigned int nr_segs) +enum bio_merge_status bio_attempt_front_merge(struct request *req, + struct bio *bio, + unsigned int nr_segs) { const int ff = bio->bi_opf & REQ_FAILFAST_MASK; if (!ll_front_merge_fn(req, bio, nr_segs)) - return false; + return BIO_MERGE_FAILED; trace_block_bio_frontmerge(req->q, req, bio); rq_qos_merge(req->q, req, bio); @@ -954,11 +956,12 @@ bool bio_attempt_front_merge(struct request *req, struct bio *bio, bio_crypt_do_front_merge(req, bio); blk_account_io_merge_bio(req); - return true; + return BIO_MERGE_OK; } -bool bio_attempt_discard_merge(struct request_queue *q, struct request *req, - struct bio *bio) +enum bio_merge_status bio_attempt_discard_merge(struct request_queue *q, + struct request *req, + struct bio *bio) { unsigned short segments = blk_rq_nr_discard_segments(req); @@ -976,10 +979,39 @@ bool bio_attempt_discard_merge(struct request_queue *q, struct request *req, req->nr_phys_segments = segments + 1; blk_account_io_merge_bio(req); - return true; + return BIO_MERGE_OK; no_merge: req_set_nomerge(q, req); - return false; + return BIO_MERGE_FAILED; +} + +static enum bio_merge_status blk_attempt_bio_merge(struct request_queue *q, + struct request *rq, + struct bio *bio, + unsigned int nr_segs, + bool sched_allow_merge) +{ + if (!blk_rq_merge_ok(rq, bio)) + return BIO_MERGE_NONE; + + switch (blk_try_merge(rq, bio)) { + case ELEVATOR_BACK_MERGE: + if (!sched_allow_merge || + (sched_allow_merge && blk_mq_sched_allow_merge(q, rq, bio))) + return bio_attempt_back_merge(rq, bio, nr_segs); + break; + case ELEVATOR_FRONT_MERGE: + if (!sched_allow_merge || + (sched_allow_merge && blk_mq_sched_allow_merge(q, rq, bio))) + return bio_attempt_front_merge(rq, bio, nr_segs); + break; + case ELEVATOR_DISCARD_MERGE: + return bio_attempt_discard_merge(q, rq, bio); + default: + return BIO_MERGE_NONE; + } + + return BIO_MERGE_FAILED; } /** @@ -1018,8 +1050,6 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, plug_list = &plug->mq_list; list_for_each_entry_reverse(rq, plug_list, queuelist) { - bool merged = false; - if (rq->q == q && same_queue_rq) { /* * Only blk-mq multiple hardware queues case checks the @@ -1029,24 +1059,11 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, *same_queue_rq = rq; } - if (rq->q != q || !blk_rq_merge_ok(rq, bio)) + if (rq->q != q) continue; - switch (blk_try_merge(rq, bio)) { - case ELEVATOR_BACK_MERGE: - merged = bio_attempt_back_merge(rq, bio, nr_segs); - break; - case ELEVATOR_FRONT_MERGE: - merged = bio_attempt_front_merge(rq, bio, nr_segs); - break; - case ELEVATOR_DISCARD_MERGE: - merged = bio_attempt_discard_merge(q, rq, bio); - break; - default: - break; - } - - if (merged) + if (blk_attempt_bio_merge(q, rq, bio, nr_segs, false) == + BIO_MERGE_OK) return true; } @@ -1064,33 +1081,18 @@ bool blk_bio_list_merge(struct request_queue *q, struct list_head *list, int checked = 8; list_for_each_entry_reverse(rq, list, queuelist) { - bool merged = false; - if (!checked--) break; - if (!blk_rq_merge_ok(rq, bio)) - continue; - - switch (blk_try_merge(rq, bio)) { - case ELEVATOR_BACK_MERGE: - if (blk_mq_sched_allow_merge(q, rq, bio)) - merged = bio_attempt_back_merge(rq, bio, - nr_segs); - break; - case ELEVATOR_FRONT_MERGE: - if (blk_mq_sched_allow_merge(q, rq, bio)) - merged = bio_attempt_front_merge(rq, bio, - nr_segs); - break; - case ELEVATOR_DISCARD_MERGE: - merged = bio_attempt_discard_merge(q, rq, bio); - break; - default: + switch (blk_attempt_bio_merge(q, rq, bio, nr_segs, true)) { + case BIO_MERGE_NONE: continue; + case BIO_MERGE_OK: + return true; + case BIO_MERGE_FAILED: + return false; } - return merged; } return false; diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 82acff96c093..94db0c9d59b8 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -368,7 +368,7 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, case ELEVATOR_BACK_MERGE: if (!blk_mq_sched_allow_merge(q, rq, bio)) return false; - if (!bio_attempt_back_merge(rq, bio, nr_segs)) + if (bio_attempt_back_merge(rq, bio, nr_segs) != BIO_MERGE_OK) return false; *merged_request = attempt_back_merge(q, rq); if (!*merged_request) @@ -377,14 +377,14 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, case ELEVATOR_FRONT_MERGE: if (!blk_mq_sched_allow_merge(q, rq, bio)) return false; - if (!bio_attempt_front_merge(rq, bio, nr_segs)) + if (bio_attempt_front_merge(rq, bio, nr_segs) != BIO_MERGE_OK) return false; *merged_request = attempt_front_merge(q, rq); if (!*merged_request) elv_merged_request(q, rq, ELEVATOR_FRONT_MERGE); return true; case ELEVATOR_DISCARD_MERGE: - return bio_attempt_discard_merge(q, rq, bio); + return bio_attempt_discard_merge(q, rq, bio) == BIO_MERGE_OK; default: return false; } diff --git a/block/blk.h b/block/blk.h index d6152d20d4e2..a180443ac13f 100644 --- a/block/blk.h +++ b/block/blk.h @@ -29,6 +29,12 @@ struct blk_flush_queue { spinlock_t mq_flush_lock; }; +enum bio_merge_status { + BIO_MERGE_OK, + BIO_MERGE_NONE, + BIO_MERGE_FAILED, +}; + extern struct kmem_cache *blk_requestq_cachep; extern struct kobj_type blk_queue_ktype; extern struct ida blk_queue_ida; @@ -169,12 +175,15 @@ static inline void blk_integrity_del(struct gendisk *disk) unsigned long blk_rq_timeout(unsigned long timeout); void blk_add_timer(struct request *req); -bool bio_attempt_front_merge(struct request *req, struct bio *bio, - unsigned int nr_segs); -bool bio_attempt_back_merge(struct request *req, struct bio *bio, - unsigned int nr_segs); -bool bio_attempt_discard_merge(struct request_queue *q, struct request *req, - struct bio *bio); +enum bio_merge_status bio_attempt_front_merge(struct request *req, + struct bio *bio, + unsigned int nr_segs); +enum bio_merge_status bio_attempt_back_merge(struct request *req, + struct bio *bio, + unsigned int nr_segs); +enum bio_merge_status bio_attempt_discard_merge(struct request_queue *q, + struct request *req, + struct bio *bio); bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, unsigned int nr_segs, struct request **same_queue_rq); bool blk_bio_list_merge(struct request_queue *q, struct list_head *list, |