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

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Message-Id: <20170626121034.3051-51-ming.lei@redhat.com>
Date:   Mon, 26 Jun 2017 20:10:33 +0800
From:   Ming Lei <ming.lei@...hat.com>
To:     Jens Axboe <axboe@...com>, Christoph Hellwig <hch@...radead.org>,
        Huang Ying <ying.huang@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Alexander Viro <viro@...iv.linux.org.uk>
Cc:     linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-mm@...ck.org,
        Ming Lei <ming.lei@...hat.com>
Subject: [PATCH v2 50/51] block: enable multipage bvecs

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@...hat.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