From: JackieLiu <liuyun01@kylinos.cn>
Date: Mon, 28 Nov 2016 08:19:19 +0000 (+0800)
Subject: md/raid5-cache: use ring add to prevent overflow
X-Git-Tag: v4.10-rc1~126^2^2~14
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fc833c2a2f4129c42efdaed64b9eb6e9ae5fdcee;p=thirdparty%2Fkernel%2Flinux.git

md/raid5-cache: use ring add to prevent overflow

'write_pos' must be protected with 'r5l_ring_add', or it may overflow

Signed-off-by: JackieLiu <liuyun01@kylinos.cn>
Reviewed-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
---

diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 1842ecbf95a10..5ef20c57731fe 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -2084,7 +2084,7 @@ r5c_recovery_rewrite_data_only_stripes(struct r5l_log *log,
 						     ctx->pos, ctx->seq);
 		mb = page_address(page);
 		offset = le32_to_cpu(mb->meta_size);
-		write_pos = ctx->pos + BLOCK_SECTORS;
+		write_pos = r5l_ring_add(log, ctx->pos, BLOCK_SECTORS);
 
 		for (i = sh->disks; i--; ) {
 			struct r5dev *dev = &sh->dev[i];