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block: move req_gap_{back,front}_merge to blk-merge.c

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Keep it close to the actual users instead of exposing the function to all
drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2018-09-24 09:43:48 +02:00 committed by Jens Axboe
parent 43b729bfe9
commit e9907009cb
2 changed files with 65 additions and 69 deletions
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65
block/blk-merge.c
View File

@ -12,6 +12,71 @@
#include "blk.h"
/*
* Check if the two bvecs from two bios can be merged to one segment. If yes,
* no need to check gap between the two bios since the 1st bio and the 1st bvec
* in the 2nd bio can be handled in one segment.
*/
static inline bool bios_segs_mergeable(struct request_queue *q,
struct bio *prev, struct bio_vec *prev_last_bv,
struct bio_vec *next_first_bv)
{
if (!BIOVEC_PHYS_MERGEABLE(prev_last_bv, next_first_bv))
return false;
if (!BIOVEC_SEG_BOUNDARY(q, prev_last_bv, next_first_bv))
return false;
if (prev->bi_seg_back_size + next_first_bv->bv_len >
queue_max_segment_size(q))
return false;
return true;
}
static inline bool bio_will_gap(struct request_queue *q,
struct request *prev_rq, struct bio *prev, struct bio *next)
{
struct bio_vec pb, nb;
if (!bio_has_data(prev) || !queue_virt_boundary(q))
return false;
/*
* Don't merge if the 1st bio starts with non-zero offset, otherwise it
* is quite difficult to respect the sg gap limit. We work hard to
* merge a huge number of small single bios in case of mkfs.
*/
if (prev_rq)
bio_get_first_bvec(prev_rq->bio, &pb);
else
bio_get_first_bvec(prev, &pb);
if (pb.bv_offset)
return true;
/*
* We don't need to worry about the situation that the merged segment
* ends in unaligned virt boundary:
*
* - if 'pb' ends aligned, the merged segment ends aligned
* - if 'pb' ends unaligned, the next bio must include
* one single bvec of 'nb', otherwise the 'nb' can't
* merge with 'pb'
*/
bio_get_last_bvec(prev, &pb);
bio_get_first_bvec(next, &nb);
if (bios_segs_mergeable(q, prev, &pb, &nb))
return false;
return __bvec_gap_to_prev(q, &pb, nb.bv_offset);
}
static inline bool req_gap_back_merge(struct request *req, struct bio *bio)
{
return bio_will_gap(req->q, req, req->biotail, bio);
}
static inline bool req_gap_front_merge(struct request *req, struct bio *bio)
{
return bio_will_gap(req->q, NULL, bio, req->bio);
}
static struct bio *blk_bio_discard_split(struct request_queue *q,
struct bio *bio,
struct bio_set *bs,

69
include/linux/blkdev.h
View File

@ -1695,75 +1695,6 @@ static inline bool bvec_gap_to_prev(struct request_queue *q,
return __bvec_gap_to_prev(q, bprv, offset);
}
/*
* Check if the two bvecs from two bios can be merged to one segment.
* If yes, no need to check gap between the two bios since the 1st bio
* and the 1st bvec in the 2nd bio can be handled in one segment.
*/
static inline bool bios_segs_mergeable(struct request_queue *q,
struct bio *prev, struct bio_vec *prev_last_bv,
struct bio_vec *next_first_bv)
{
if (!BIOVEC_PHYS_MERGEABLE(prev_last_bv, next_first_bv))
return false;
if (!BIOVEC_SEG_BOUNDARY(q, prev_last_bv, next_first_bv))
return false;
if (prev->bi_seg_back_size + next_first_bv->bv_len >
queue_max_segment_size(q))
return false;
return true;
}
static inline bool bio_will_gap(struct request_queue *q,
struct request *prev_rq,
struct bio *prev,
struct bio *next)
{
if (bio_has_data(prev) && queue_virt_boundary(q)) {
struct bio_vec pb, nb;
/*
* don't merge if the 1st bio starts with non-zero
* offset, otherwise it is quite difficult to respect
* sg gap limit. We work hard to merge a huge number of small
* single bios in case of mkfs.
*/
if (prev_rq)
bio_get_first_bvec(prev_rq->bio, &pb);
else
bio_get_first_bvec(prev, &pb);
if (pb.bv_offset)
return true;
/*
* We don't need to worry about the situation that the
* merged segment ends in unaligned virt boundary:
*
* - if 'pb' ends aligned, the merged segment ends aligned
* - if 'pb' ends unaligned, the next bio must include
* one single bvec of 'nb', otherwise the 'nb' can't
* merge with 'pb'
*/
bio_get_last_bvec(prev, &pb);
bio_get_first_bvec(next, &nb);
if (!bios_segs_mergeable(q, prev, &pb, &nb))
return __bvec_gap_to_prev(q, &pb, nb.bv_offset);
}
return false;
}
static inline bool req_gap_back_merge(struct request *req, struct bio *bio)
{
return bio_will_gap(req->q, req, req->biotail, bio);
}
static inline bool req_gap_front_merge(struct request *req, struct bio *bio)
{
return bio_will_gap(req->q, NULL, bio, req->bio);
}
int kblockd_schedule_work(struct work_struct *work);
int kblockd_schedule_work_on(int cpu, struct work_struct *work);
int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);