From 34fe7c05400663e01e23cddd1fea68bb7a2b3d29 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 8 Feb 2017 14:46:48 +0100 Subject: [PATCH] block: enumify ELEVATOR_*_MERGE Switch these constants to an enum, and make let the compiler ensure that all callers of blk_try_merge and elv_merge handle all potential values. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/blk-core.c | 76 +++++++++++++++++++++------------------- block/blk-merge.c | 2 +- block/blk-mq-sched.c | 35 +++++++++--------- block/blk-mq.c | 34 ++++++++---------- block/blk.h | 2 +- block/cfq-iosched.c | 4 +-- block/deadline-iosched.c | 12 +++---- block/elevator.c | 10 +++--- block/mq-deadline.c | 2 +- include/linux/elevator.h | 28 ++++++++------- 10 files changed, 103 insertions(+), 102 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 1d263311353a..00e053c704a1 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1511,12 +1511,11 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, { struct blk_plug *plug; struct request *rq; - bool ret = false; struct list_head *plug_list; plug = current->plug; if (!plug) - goto out; + return false; *request_count = 0; if (q->mq_ops) @@ -1525,7 +1524,7 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, plug_list = &plug->list; list_for_each_entry_reverse(rq, plug_list, queuelist) { - int el_ret; + bool merged = false; if (rq->q == q) { (*request_count)++; @@ -1541,19 +1540,22 @@ bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, if (rq->q != q || !blk_rq_merge_ok(rq, bio)) continue; - el_ret = blk_try_merge(rq, bio); - if (el_ret == ELEVATOR_BACK_MERGE) { - ret = bio_attempt_back_merge(q, rq, bio); - if (ret) - break; - } else if (el_ret == ELEVATOR_FRONT_MERGE) { - ret = bio_attempt_front_merge(q, rq, bio); - if (ret) - break; + switch (blk_try_merge(rq, bio)) { + case ELEVATOR_BACK_MERGE: + merged = bio_attempt_back_merge(q, rq, bio); + break; + case ELEVATOR_FRONT_MERGE: + merged = bio_attempt_front_merge(q, rq, bio); + break; + default: + break; } + + if (merged) + return true; } -out: - return ret; + + return false; } unsigned int blk_plug_queued_count(struct request_queue *q) @@ -1595,7 +1597,7 @@ void init_request_from_bio(struct request *req, struct bio *bio) static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) { struct blk_plug *plug; - int el_ret, where = ELEVATOR_INSERT_SORT; + int where = ELEVATOR_INSERT_SORT; struct request *req, *free; unsigned int request_count = 0; unsigned int wb_acct; @@ -1633,27 +1635,29 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) spin_lock_irq(q->queue_lock); - el_ret = elv_merge(q, &req, bio); - if (el_ret == ELEVATOR_BACK_MERGE) { - if (bio_attempt_back_merge(q, req, bio)) { - elv_bio_merged(q, req, bio); - free = attempt_back_merge(q, req); - if (!free) - elv_merged_request(q, req, el_ret); - else - __blk_put_request(q, free); - goto out_unlock; - } - } else if (el_ret == ELEVATOR_FRONT_MERGE) { - if (bio_attempt_front_merge(q, req, bio)) { - elv_bio_merged(q, req, bio); - free = attempt_front_merge(q, req); - if (!free) - elv_merged_request(q, req, el_ret); - else - __blk_put_request(q, free); - goto out_unlock; - } + switch (elv_merge(q, &req, bio)) { + case ELEVATOR_BACK_MERGE: + if (!bio_attempt_back_merge(q, req, bio)) + break; + elv_bio_merged(q, req, bio); + free = attempt_back_merge(q, req); + if (free) + __blk_put_request(q, free); + else + elv_merged_request(q, req, ELEVATOR_BACK_MERGE); + goto out_unlock; + case ELEVATOR_FRONT_MERGE: + if (!bio_attempt_front_merge(q, req, bio)) + break; + elv_bio_merged(q, req, bio); + free = attempt_front_merge(q, req); + if (free) + __blk_put_request(q, free); + else + elv_merged_request(q, req, ELEVATOR_FRONT_MERGE); + goto out_unlock; + default: + break; } get_rq: diff --git a/block/blk-merge.c b/block/blk-merge.c index c956d9e7aafd..6cbd90ad5f90 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -801,7 +801,7 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio) return true; } -int blk_try_merge(struct request *rq, struct bio *bio) +enum elv_merge blk_try_merge(struct request *rq, struct bio *bio) { if (blk_rq_pos(rq) + blk_rq_sectors(rq) == bio->bi_iter.bi_sector) return ELEVATOR_BACK_MERGE; diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index ee455e7cf9d8..72d0d8361175 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -238,30 +238,29 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, struct request **merged_request) { struct request *rq; - int ret; - ret = elv_merge(q, &rq, bio); - if (ret == ELEVATOR_BACK_MERGE) { + switch (elv_merge(q, &rq, bio)) { + case ELEVATOR_BACK_MERGE: if (!blk_mq_sched_allow_merge(q, rq, bio)) return false; - if (bio_attempt_back_merge(q, rq, bio)) { - *merged_request = attempt_back_merge(q, rq); - if (!*merged_request) - elv_merged_request(q, rq, ret); - return true; - } - } else if (ret == ELEVATOR_FRONT_MERGE) { + if (!bio_attempt_back_merge(q, rq, bio)) + return false; + *merged_request = attempt_back_merge(q, rq); + if (!*merged_request) + elv_merged_request(q, rq, ELEVATOR_BACK_MERGE); + return true; + case ELEVATOR_FRONT_MERGE: if (!blk_mq_sched_allow_merge(q, rq, bio)) return false; - if (bio_attempt_front_merge(q, rq, bio)) { - *merged_request = attempt_front_merge(q, rq); - if (!*merged_request) - elv_merged_request(q, rq, ret); - return true; - } + if (!bio_attempt_front_merge(q, rq, bio)) + return false; + *merged_request = attempt_front_merge(q, rq); + if (!*merged_request) + elv_merged_request(q, rq, ELEVATOR_FRONT_MERGE); + return true; + default: + return false; } - - return false; } EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge); diff --git a/block/blk-mq.c b/block/blk-mq.c index e9957df05700..dd9722df4afe 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -763,7 +763,7 @@ static bool blk_mq_attempt_merge(struct request_queue *q, int checked = 8; list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { - int el_ret; + bool merged = false; if (!checked--) break; @@ -771,26 +771,22 @@ static bool blk_mq_attempt_merge(struct request_queue *q, if (!blk_rq_merge_ok(rq, bio)) continue; - el_ret = blk_try_merge(rq, bio); - if (el_ret == ELEVATOR_NO_MERGE) + switch (blk_try_merge(rq, bio)) { + case ELEVATOR_BACK_MERGE: + if (blk_mq_sched_allow_merge(q, rq, bio)) + merged = bio_attempt_back_merge(q, rq, bio); + break; + case ELEVATOR_FRONT_MERGE: + if (blk_mq_sched_allow_merge(q, rq, bio)) + merged = bio_attempt_front_merge(q, rq, bio); + break; + default: continue; - - if (!blk_mq_sched_allow_merge(q, rq, bio)) - break; - - if (el_ret == ELEVATOR_BACK_MERGE) { - if (bio_attempt_back_merge(q, rq, bio)) { - ctx->rq_merged++; - return true; - } - break; - } else if (el_ret == ELEVATOR_FRONT_MERGE) { - if (bio_attempt_front_merge(q, rq, bio)) { - ctx->rq_merged++; - return true; - } - break; } + + if (merged) + ctx->rq_merged++; + return merged; } return false; diff --git a/block/blk.h b/block/blk.h index 3e08703902a9..ae82f2ac4019 100644 --- a/block/blk.h +++ b/block/blk.h @@ -215,7 +215,7 @@ int blk_attempt_req_merge(struct request_queue *q, struct request *rq, void blk_recalc_rq_segments(struct request *rq); void blk_rq_set_mixed_merge(struct request *rq); bool blk_rq_merge_ok(struct request *rq, struct bio *bio); -int blk_try_merge(struct request *rq, struct bio *bio); +enum elv_merge blk_try_merge(struct request *rq, struct bio *bio); void blk_queue_congestion_threshold(struct request_queue *q); diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index f0f29ee731e1..921262770636 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -2528,7 +2528,7 @@ static void cfq_remove_request(struct request *rq) } } -static int cfq_merge(struct request_queue *q, struct request **req, +static enum elv_merge cfq_merge(struct request_queue *q, struct request **req, struct bio *bio) { struct cfq_data *cfqd = q->elevator->elevator_data; @@ -2544,7 +2544,7 @@ static int cfq_merge(struct request_queue *q, struct request **req, } static void cfq_merged_request(struct request_queue *q, struct request *req, - int type) + enum elv_merge type) { if (type == ELEVATOR_FRONT_MERGE) { struct cfq_queue *cfqq = RQ_CFQQ(req); diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c index 05fc0ea25a98..c68f6bbc0dcd 100644 --- a/block/deadline-iosched.c +++ b/block/deadline-iosched.c @@ -120,12 +120,11 @@ static void deadline_remove_request(struct request_queue *q, struct request *rq) deadline_del_rq_rb(dd, rq); } -static int +static enum elv_merge deadline_merge(struct request_queue *q, struct request **req, struct bio *bio) { struct deadline_data *dd = q->elevator->elevator_data; struct request *__rq; - int ret; /* * check for front merge @@ -138,20 +137,17 @@ deadline_merge(struct request_queue *q, struct request **req, struct bio *bio) BUG_ON(sector != blk_rq_pos(__rq)); if (elv_bio_merge_ok(__rq, bio)) { - ret = ELEVATOR_FRONT_MERGE; - goto out; + *req = __rq; + return ELEVATOR_FRONT_MERGE; } } } return ELEVATOR_NO_MERGE; -out: - *req = __rq; - return ret; } static void deadline_merged_request(struct request_queue *q, - struct request *req, int type) + struct request *req, enum elv_merge type) { struct deadline_data *dd = q->elevator->elevator_data; diff --git a/block/elevator.c b/block/elevator.c index 7e4f5880dd64..27ff1ed5a6fa 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -427,11 +427,11 @@ void elv_dispatch_add_tail(struct request_queue *q, struct request *rq) } EXPORT_SYMBOL(elv_dispatch_add_tail); -int elv_merge(struct request_queue *q, struct request **req, struct bio *bio) +enum elv_merge elv_merge(struct request_queue *q, struct request **req, + struct bio *bio) { struct elevator_queue *e = q->elevator; struct request *__rq; - int ret; /* * Levels of merges: @@ -446,7 +446,8 @@ int elv_merge(struct request_queue *q, struct request **req, struct bio *bio) * First try one-hit cache. */ if (q->last_merge && elv_bio_merge_ok(q->last_merge, bio)) { - ret = blk_try_merge(q->last_merge, bio); + enum elv_merge ret = blk_try_merge(q->last_merge, bio); + if (ret != ELEVATOR_NO_MERGE) { *req = q->last_merge; return ret; @@ -514,7 +515,8 @@ bool elv_attempt_insert_merge(struct request_queue *q, struct request *rq) return ret; } -void elv_merged_request(struct request_queue *q, struct request *rq, int type) +void elv_merged_request(struct request_queue *q, struct request *rq, + enum elv_merge type) { struct elevator_queue *e = q->elevator; diff --git a/block/mq-deadline.c b/block/mq-deadline.c index d68d9c273a66..236121633ca0 100644 --- a/block/mq-deadline.c +++ b/block/mq-deadline.c @@ -121,7 +121,7 @@ static void deadline_remove_request(struct request_queue *q, struct request *rq) } static void dd_request_merged(struct request_queue *q, struct request *req, - int type) + enum elv_merge type) { struct deadline_data *dd = q->elevator->elevator_data; diff --git a/include/linux/elevator.h b/include/linux/elevator.h index b5825c4f06f7..b38b4e651ea6 100644 --- a/include/linux/elevator.h +++ b/include/linux/elevator.h @@ -9,12 +9,21 @@ struct io_cq; struct elevator_type; -typedef int (elevator_merge_fn) (struct request_queue *, struct request **, +/* + * Return values from elevator merger + */ +enum elv_merge { + ELEVATOR_NO_MERGE = 0, + ELEVATOR_FRONT_MERGE = 1, + ELEVATOR_BACK_MERGE = 2, +}; + +typedef enum elv_merge (elevator_merge_fn) (struct request_queue *, struct request **, struct bio *); typedef void (elevator_merge_req_fn) (struct request_queue *, struct request *, struct request *); -typedef void (elevator_merged_fn) (struct request_queue *, struct request *, int); +typedef void (elevator_merged_fn) (struct request_queue *, struct request *, enum elv_merge); typedef int (elevator_allow_bio_merge_fn) (struct request_queue *, struct request *, struct bio *); @@ -87,7 +96,7 @@ struct elevator_mq_ops { bool (*allow_merge)(struct request_queue *, struct request *, struct bio *); bool (*bio_merge)(struct blk_mq_hw_ctx *, struct bio *); int (*request_merge)(struct request_queue *q, struct request **, struct bio *); - void (*request_merged)(struct request_queue *, struct request *, int); + void (*request_merged)(struct request_queue *, struct request *, enum elv_merge); void (*requests_merged)(struct request_queue *, struct request *, struct request *); struct request *(*get_request)(struct request_queue *, unsigned int, struct blk_mq_alloc_data *); void (*put_request)(struct request *); @@ -166,10 +175,12 @@ extern void elv_dispatch_sort(struct request_queue *, struct request *); extern void elv_dispatch_add_tail(struct request_queue *, struct request *); extern void elv_add_request(struct request_queue *, struct request *, int); extern void __elv_add_request(struct request_queue *, struct request *, int); -extern int elv_merge(struct request_queue *, struct request **, struct bio *); +extern enum elv_merge elv_merge(struct request_queue *, struct request **, + struct bio *); extern void elv_merge_requests(struct request_queue *, struct request *, struct request *); -extern void elv_merged_request(struct request_queue *, struct request *, int); +extern void elv_merged_request(struct request_queue *, struct request *, + enum elv_merge); extern void elv_bio_merged(struct request_queue *q, struct request *, struct bio *); extern bool elv_attempt_insert_merge(struct request_queue *, struct request *); @@ -218,13 +229,6 @@ extern void elv_rb_add(struct rb_root *, struct request *); extern void elv_rb_del(struct rb_root *, struct request *); extern struct request *elv_rb_find(struct rb_root *, sector_t); -/* - * Return values from elevator merger - */ -#define ELEVATOR_NO_MERGE 0 -#define ELEVATOR_FRONT_MERGE 1 -#define ELEVATOR_BACK_MERGE 2 - /* * Insertion selection */