Commit 76830840 authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

NVMe: Handle physical merging of bvec entries 



In order to not overrun the sg array, we have to merge physically
contiguous pages into a single sg entry.

Signed-off-by: default avatarMatthew Wilcox <matthew.r.wilcox@intel.com>
parent 1974b1ae

drivers/block/nvme.c

+15 −9
Original line number Diff line number Diff line
@@ -392,19 +392,25 @@ static struct nvme_prps *nvme_setup_prps(struct nvme_dev *dev, 
static int nvme_map_bio(struct device *dev, struct nvme_bio *nbio,

		struct bio *bio, enum dma_data_direction dma_dir, int psegs)

{

	struct bio_vec *bvec;

	struct scatterlist *sg = nbio->sg;

	int i, nsegs;

	struct bio_vec *bvec, *bvprv = NULL;

	struct scatterlist *sg = NULL;

	int i, nsegs = 0;



	sg_init_table(sg, psegs);

	sg_init_table(nbio->sg, psegs);

	bio_for_each_segment(bvec, bio, i) {

		sg_set_page(sg, bvec->bv_page, bvec->bv_len, bvec->bv_offset);

		sg++;

		/* XXX: handle non-mergable here */

		if (bvprv && BIOVEC_PHYS_MERGEABLE(bvprv, bvec)) {

			sg->length += bvec->bv_len;

		} else {

			/* Check bvprv && offset == 0 */

			sg = sg ? sg + 1 : nbio->sg;

			sg_set_page(sg, bvec->bv_page, bvec->bv_len,

							bvec->bv_offset);

			nsegs++;

		}

		bvprv = bvec;

	}

	nbio->nents = nsegs;



	sg_mark_end(sg);

	return dma_map_sg(dev, nbio->sg, nbio->nents, dma_dir);

}