In order to support dma-direct bios, blk_bio_segment_split() will need to operate on both bio_vecs and dma_vecs. In order to do this, the code inside bio_for_each_bvec() is moved into a generic helper called bvec_should_split().
Signed-off-by: Logan Gunthorpe <[email protected]> --- block/blk-merge.c | 86 +++++++++++++++++++++++++---------------------- 1 file changed, 46 insertions(+), 40 deletions(-) diff --git a/block/blk-merge.c b/block/blk-merge.c index 414e61a714bf..d9e89c0ad40d 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -212,6 +212,48 @@ struct blk_segment_split_ctx { const unsigned max_segs; }; +static bool bvec_should_split(struct request_queue *q, struct bio_vec *bv, + struct blk_segment_split_ctx *ctx) +{ + /* + * If the queue doesn't support SG gaps and adding this + * offset would create a gap, disallow it. + */ + if (ctx->prv_valid && bvec_gap_to_prev(q, &ctx->bvprv, bv->bv_offset)) + return true; + + if (ctx->sectors + (bv->bv_len >> 9) > ctx->max_sectors) { + /* + * Consider this a new segment if we're splitting in + * the middle of this vector. + */ + if (ctx->nsegs < ctx->max_segs && + ctx->sectors < ctx->max_sectors) { + /* split in the middle of bvec */ + bv->bv_len = (ctx->max_sectors - ctx->sectors) << 9; + bvec_split_segs(q, bv, &ctx->nsegs, + &ctx->sectors, ctx->max_segs); + } + return true; + } + + if (ctx->nsegs == ctx->max_segs) + return true; + + ctx->bvprv = *bv; + ctx->prv_valid = true; + + if (bv->bv_offset + bv->bv_len <= PAGE_SIZE) { + ctx->nsegs++; + ctx->sectors += bv->bv_len >> 9; + } else if (bvec_split_segs(q, bv, &ctx->nsegs, &ctx->sectors, + ctx->max_segs)) { + return true; + } + + return false; +} + static struct bio *blk_bio_segment_split(struct request_queue *q, struct bio *bio, struct bio_set *bs, @@ -219,7 +261,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, { struct bio_vec bv; struct bvec_iter iter; - bool do_split = true; + bool do_split = false; struct bio *new = NULL; struct blk_segment_split_ctx ctx = { @@ -228,47 +270,11 @@ static struct bio *blk_bio_segment_split(struct request_queue *q, }; bio_for_each_bvec(bv, bio, iter) { - /* - * If the queue doesn't support SG gaps and adding this - * offset would create a gap, disallow it. - */ - if (ctx.prv_valid && bvec_gap_to_prev(q, &ctx.bvprv, - bv.bv_offset)) - goto split; - - if (ctx.sectors + (bv.bv_len >> 9) > ctx.max_sectors) { - /* - * Consider this a new segment if we're splitting in - * the middle of this vector. - */ - if (ctx.nsegs < ctx.max_segs && - ctx.sectors < ctx.max_sectors) { - /* split in the middle of bvec */ - bv.bv_len = - (ctx.max_sectors - ctx.sectors) << 9; - bvec_split_segs(q, &bv, &ctx.nsegs, - &ctx.sectors, ctx.max_segs); - } - goto split; - } - - if (ctx.nsegs == ctx.max_segs) - goto split; - - ctx.bvprv = bv; - ctx.prv_valid = true; - - if (bv.bv_offset + bv.bv_len <= PAGE_SIZE) { - ctx.nsegs++; - ctx.sectors += bv.bv_len >> 9; - } else if (bvec_split_segs(q, &bv, &ctx.nsegs, &ctx.sectors, - ctx.max_segs)) { - goto split; - } + do_split = bvec_should_split(q, &bv, &ctx); + if (do_split) + break; } - do_split = false; -split: *segs = ctx.nsegs; if (do_split) { -- 2.20.1
