linux-kernel - [PATCH v2 11/51] md: raid1: initialize bvec table via bio_add

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Message-Id: <20170626121034.3051-12-ming.lei@redhat.com>
Date:   Mon, 26 Jun 2017 20:09:54 +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>, Shaohua Li <shli@...nel.org>,
        linux-raid@...r.kernel.org
Subject: [PATCH v2 11/51] md: raid1: initialize bvec table via bio_add_page()

We will support multipage bvec soon, so initialize bvec
table using the standardy way instead of writing the
talbe directly. Otherwise it won't work any more once
multipage bvec is enabled.

Cc: Shaohua Li <shli@...nel.org>
Cc: linux-raid@...r.kernel.org
Signed-off-by: Ming Lei <ming.lei@...hat.com>
---
 drivers/md/raid1.c | 27 ++++++++++++++-------------
 1 file changed, 14 insertions(+), 13 deletions(-)

diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 3febfc8391fb..835c42396861 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -2086,10 +2086,8 @@ static void process_checks(struct r1bio *r1_bio)
 	/* Fix variable parts of all bios */
 	vcnt = (r1_bio->sectors + PAGE_SIZE / 512 - 1) >> (PAGE_SHIFT - 9);
 	for (i = 0; i < conf->raid_disks * 2; i++) {
-		int j;
 		int size;
 		blk_status_t status;
-		struct bio_vec *bi;
 		struct bio *b = r1_bio->bios[i];
 		struct resync_pages *rp = get_resync_pages(b);
 		if (b->bi_end_io != end_sync_read)
@@ -2098,8 +2096,6 @@ static void process_checks(struct r1bio *r1_bio)
 		status = b->bi_status;
 		bio_reset(b);
 		b->bi_status = status;
-		b->bi_vcnt = vcnt;
-		b->bi_iter.bi_size = r1_bio->sectors << 9;
 		b->bi_iter.bi_sector = r1_bio->sector +
 			conf->mirrors[i].rdev->data_offset;
 		b->bi_bdev = conf->mirrors[i].rdev->bdev;
@@ -2107,15 +2103,20 @@ static void process_checks(struct r1bio *r1_bio)
 		rp->raid_bio = r1_bio;
 		b->bi_private = rp;
 
-		size = b->bi_iter.bi_size;
-		bio_for_each_segment_all(bi, b, j) {
-			bi->bv_offset = 0;
-			if (size > PAGE_SIZE)
-				bi->bv_len = PAGE_SIZE;
-			else
-				bi->bv_len = size;
-			size -= PAGE_SIZE;
-		}
+		/* initialize bvec table again */
+		rp->idx = 0;
+		size = r1_bio->sectors << 9;
+		do {
+			struct page *page = resync_fetch_page(rp, rp->idx++);
+			int len = min_t(int, size, PAGE_SIZE);
+
+			/*
+			 * won't fail because the vec table is big
+			 * enough to hold all these pages
+			 */
+			bio_add_page(b, page, len, 0);
+			size -= len;
+		} while (rp->idx < RESYNC_PAGES && size > 0);
 	}
 	for (primary = 0; primary < conf->raid_disks * 2; primary++)
 		if (r1_bio->bios[primary]->bi_end_io == end_sync_read &&
-- 
2.9.4