[PATCH v2 50/51] block: enable multipage bvecs

Ming Lei
2017-06-26T12:10:33Z

This patch pulls the trigger for multipage bvecs.

Now any request queue which supports queue cluster
will see multipage bvecs.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/bio.c | 13 +++++++++++++
1 file changed, 13 insertions(+)

diff --git a/block/bio.c b/block/bio.c
index c460888f14b5..436305cde045 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -839,6 +839,11 @@ int bio_add_page(struct bio *bio, struct page *page,
* a consecutive offset. Optimize this special case.
*/
if (bio->bi_vcnt > 0) {
+ struct request_queue *q = NULL;
+
+ if (bio->bi_bdev)
+ q = bdev_get_queue(bio->bi_bdev);
+
bv = &bio->bi_io_vec[bio->bi_vcnt - 1];

if (page == bv->bv_page &&
@@ -846,6 +851,14 @@ int bio_add_page(struct bio *bio, struct page *page,
bv->bv_len += len;
goto done;
}
+
+ /* disable multipage bvec too if cluster isn't enabled */
+ if (q && blk_queue_cluster(q) &&
+ (bvec_to_phys(bv) + bv->bv_len ==
+ page_to_phys(page) + offset)) {
+ bv->bv_len += len;
+ goto done;
+ }
}

if (bio->bi_vcnt >= bio->bi_max_vecs)
--
2.9.4