[PATCH V4 42/45] block: enable multipage bvecs

Ming Lei
2017-12-18T12:33:11Z

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 e82e4c815dbb..34af328681a8 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -845,6 +845,11 @@ 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_disk)
+ q = bio->bi_disk->queue;
+
bv = &bio->bi_io_vec[bio->bi_vcnt - 1];

if (page == bv->bv_page &&
@@ -852,6 +857,14 @@ 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)
--
2.9.5