linux-kernel - [PATCH V7 20/24] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc

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Date:   Wed, 27 Jun 2018 20:45:44 +0800
From:   Ming Lei <ming.lei@...hat.com>
To:     Jens Axboe <axboe@...com>, Christoph Hellwig <hch@...radead.org>,
        Kent Overstreet <kent.overstreet@...il.com>
Cc:     David Sterba <dsterba@...e.cz>, Huang Ying <ying.huang@...el.com>,
        Mike Snitzer <snitzer@...hat.com>,
        linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-mm@...ck.org,
        Theodore Ts'o <tytso@....edu>,
        "Darrick J . Wong" <darrick.wong@...cle.com>,
        Coly Li <colyli@...e.de>, Filipe Manana <fdmanana@...il.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Ming Lei <ming.lei@...hat.com>, linux-bcache@...r.kernel.org
Subject: [PATCH V7 20/24] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages()

bch_bio_alloc_pages() is always called on one new bio, so it is safe
to access the bvec table directly. Given it is the only kind of this
case, open code the bvec table access since bio_for_each_segment_all()
will be changed to support for iterating over multipage bvec.

Cc: Coly Li <colyli@...e.de>
Cc: linux-bcache@...r.kernel.org
Signed-off-by: Ming Lei <ming.lei@...hat.com>
---
 drivers/md/bcache/util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
index fc479b026d6d..9f2a6fd5dfc9 100644
--- a/drivers/md/bcache/util.c
+++ b/drivers/md/bcache/util.c
@@ -268,7 +268,7 @@ int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
 	int i;
 	struct bio_vec *bv;
 
-	bio_for_each_segment_all(bv, bio, i) {
+	for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++) {
 		bv->bv_page = alloc_page(gfp_mask);
 		if (!bv->bv_page) {
 			while (--bv >= bio->bi_io_vec)
-- 
2.9.5