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Commit e9907009 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

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



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

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 43b729bf
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+65 −0
Original line number Diff line number Diff line
@@ -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,
+0 −69
Original line number Diff line number Diff line
@@ -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);