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block: enumify ELEVATOR_*_MERGE

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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 <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Christoph Hellwig 2017-02-08 14:46:48 +01:00 committed by Jens Axboe
parent 6cf7677f1a
commit 34fe7c0540
10 changed files with 103 additions and 102 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
block/blk-core.c
View File

@ -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:

2
block/blk-merge.c
View File

@ -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;

35
block/blk-mq-sched.c
View File

@ -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);

34
block/blk-mq.c
View File

@ -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;

2
block/blk.h
View File

@ -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);

4
block/cfq-iosched.c
View File

@ -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);

12
block/deadline-iosched.c
View File

@ -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;

10
block/elevator.c
View File

@ -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;

2
block/mq-deadline.c
View File

@ -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;

28
include/linux/elevator.h
View File

@ -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
*/