Commit dae75dea authored by Keith Busch's avatar Keith Busch Committed by Jens Axboe
Browse files

blk-mq-dma: provide the bio_vec array being iterated 



This will make it easier to add different sources of the bvec array,
like for upcoming integrity support, rather than assume to use the bio's
bi_io_vec. It also makes iterating "special" payloads more in common
with iterating normal payloads.

Signed-off-by: default avatarKeith Busch <kbusch@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarKanchan Joshi <joshi.k@samsung.com>
Reviewed-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20250813153153.3260897-3-kbusch@meta.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 7a6fc163

block/blk-mq-dma.c

+33 −23
Original line number Diff line number Diff line
@@ -16,23 +16,14 @@ static bool blk_map_iter_next(struct request *req, struct blk_map_iter *iter, 
	unsigned int max_size;

	struct bio_vec bv;



	if (req->rq_flags & RQF_SPECIAL_PAYLOAD) {

		if (!iter->bio)

			return false;

		vec->paddr = bvec_phys(&req->special_vec);

		vec->len = req->special_vec.bv_len;

		iter->bio = NULL;

		return true;

	}



	if (!iter->iter.bi_size)

		return false;



	bv = mp_bvec_iter_bvec(iter->bio->bi_io_vec, iter->iter);

	bv = mp_bvec_iter_bvec(iter->bvecs, iter->iter);

	vec->paddr = bvec_phys(&bv);

	max_size = get_max_segment_size(&req->q->limits, vec->paddr, UINT_MAX);

	bv.bv_len = min(bv.bv_len, max_size);

	bio_advance_iter_single(iter->bio, &iter->iter, bv.bv_len);

	bvec_iter_advance_single(iter->bvecs, &iter->iter, bv.bv_len);



	/*

	 * If we are entirely done with this bi_io_vec entry, check if the next
@@ -43,19 +34,20 @@ static bool blk_map_iter_next(struct request *req, struct blk_map_iter *iter, 
		struct bio_vec next;



		if (!iter->iter.bi_size) {

			if (!iter->bio->bi_next)

			if (!iter->bio || !iter->bio->bi_next)

				break;

			iter->bio = iter->bio->bi_next;

			iter->iter = iter->bio->bi_iter;

			iter->bvecs = iter->bio->bi_io_vec;

		}



		next = mp_bvec_iter_bvec(iter->bio->bi_io_vec, iter->iter);

		next = mp_bvec_iter_bvec(iter->bvecs, iter->iter);

		if (bv.bv_len + next.bv_len > max_size ||

		    !biovec_phys_mergeable(req->q, &bv, &next))

			break;



		bv.bv_len += next.bv_len;

		bio_advance_iter_single(iter->bio, &iter->iter, next.bv_len);

		bvec_iter_advance_single(iter->bvecs, &iter->iter, next.bv_len);

	}



	vec->len = bv.bv_len;
@@ -125,6 +117,30 @@ static bool blk_rq_dma_map_iova(struct request *req, struct device *dma_dev, 
	return true;

}



static inline void blk_rq_map_iter_init(struct request *rq,

					struct blk_map_iter *iter)

{

	struct bio *bio = rq->bio;



	if (rq->rq_flags & RQF_SPECIAL_PAYLOAD) {

		*iter = (struct blk_map_iter) {

			.bvecs = &rq->special_vec,

			.iter = {

				.bi_size = rq->special_vec.bv_len,

			}

		};

       } else if (bio) {

		*iter = (struct blk_map_iter) {

			.bio = bio,

			.bvecs = bio->bi_io_vec,

			.iter = bio->bi_iter,

		};

	} else {

		/* the internal flush request may not have bio attached */

	        *iter = (struct blk_map_iter) {};

	}

}



/**

 * blk_rq_dma_map_iter_start - map the first DMA segment for a request

 * @req:	request to map
@@ -153,8 +169,7 @@ bool blk_rq_dma_map_iter_start(struct request *req, struct device *dma_dev, 
	unsigned int total_len = blk_rq_payload_bytes(req);

	struct phys_vec vec;



	iter->iter.bio = req->bio;

	iter->iter.iter = req->bio->bi_iter;

	blk_rq_map_iter_init(req, &iter->iter);

	memset(&iter->p2pdma, 0, sizeof(iter->p2pdma));

	iter->status = BLK_STS_OK;
@@ -246,16 +261,11 @@ blk_next_sg(struct scatterlist **sg, struct scatterlist *sglist) 
int __blk_rq_map_sg(struct request *rq, struct scatterlist *sglist,

		    struct scatterlist **last_sg)

{

	struct blk_map_iter iter = {

		.bio	= rq->bio,

	};

	struct blk_map_iter iter;

	struct phys_vec vec;

	int nsegs = 0;



	/* the internal flush request may not have bio attached */

	if (iter.bio)

		iter.iter = iter.bio->bi_iter;



	blk_rq_map_iter_init(rq, &iter);

	while (blk_map_iter_next(rq, &iter, &vec)) {

		*last_sg = blk_next_sg(last_sg, sglist);

		sg_set_page(*last_sg, phys_to_page(vec.paddr), vec.len,

include/linux/blk-mq-dma.h

+1 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ 
struct blk_map_iter {

	struct bvec_iter		iter;

	struct bio			*bio;

	struct bio_vec			*bvecs;

};



struct blk_dma_iter {