From 7dedd15dd2527055390b9742c87a02556d3180f4 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 14 Apr 2016 12:31:49 +0300 Subject: [PATCH 1/4] md/raid0: fix uninitialized variable bug If this function fails the callers expect that *private_conf is set to an ERR_PTR() but that isn't true for the first error path where we can't allocate "conf". It leads to some uninitialized variable bugs. Signed-off-by: Dan Carpenter Signed-off-by: Shaohua Li --- drivers/md/raid0.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c index 2ea12c6bf659..f63dbb68e3a9 100644 --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -85,6 +85,7 @@ static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) struct r0conf *conf = kzalloc(sizeof(*conf), GFP_KERNEL); unsigned short blksize = 512; + *private_conf = ERR_PTR(-ENOMEM); if (!conf) return -ENOMEM; rdev_for_each(rdev1, mddev) { From b297874a2d5c5fcaeb5242a8b4708e54c5477d90 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Micha=C5=82=20Pecio?= Date: Sun, 24 Apr 2016 18:11:45 +0200 Subject: [PATCH 2/4] md/raid0: remove empty line printk from dump_zones Remove the final printk. All preceding output is already properly newline-terminated and the printk isn't even KERN_CONT to begin with, so it only adds one empty line to the log. Signed-off-by: Michal Pecio Signed-off-by: Shaohua Li --- drivers/md/raid0.c | 1 - 1 file changed, 1 deletion(-) diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c index f63dbb68e3a9..34783a3c8b3c 100644 --- a/drivers/md/raid0.c +++ b/drivers/md/raid0.c @@ -70,7 +70,6 @@ static void dump_zones(struct mddev *mddev) (unsigned long long)zone_size>>1); zone_start = conf->strip_zone[j].zone_end; } - printk(KERN_INFO "\n"); } static int create_strip_zones(struct mddev *mddev, struct r0conf **private_conf) From 9c573de3283af007ea11c17bde1e4568d9417328 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Mon, 25 Apr 2016 16:52:38 -0700 Subject: [PATCH 3/4] MD: make bio mergeable blk_queue_split marks bio unmergeable, which makes sense for normal bio. But if dispatching the bio to underlayer disk, the blk_queue_split checks are invalid, hence it's possible the bio becomes mergeable. In the reported bug, this bug causes trim against raid0 performance slash https://bugzilla.kernel.org/show_bug.cgi?id=117051 Reported-and-tested-by: Park Ju Hyung Fixes: 6ac45aeb6bca(block: avoid to merge splitted bio) Cc: stable@vger.kernel.org (v4.3+) Cc: Ming Lei Cc: Neil Brown Reviewed-by: Jens Axboe Signed-off-by: Shaohua Li --- drivers/md/md.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/md/md.c b/drivers/md/md.c index 194580fba7fd..14d3b37944df 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -284,6 +284,8 @@ static blk_qc_t md_make_request(struct request_queue *q, struct bio *bio) * go away inside make_request */ sectors = bio_sectors(bio); + /* bio could be mergeable after passing to underlayer */ + bio->bi_rw &= ~REQ_NOMERGE; mddev->pers->make_request(mddev, bio); cpu = part_stat_lock(); From b8a0b8e94648179b92191e5cf4fd3c4379b31cc4 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Fri, 29 Apr 2016 14:18:03 -0700 Subject: [PATCH 4/4] raid5: delete unnecessary warnning If device has R5_LOCKED set, it's legit device has R5_SkipCopy set and page != orig_page. After R5_LOCKED is clear, handle_stripe_clean_event will clear the SkipCopy flag and set page to orig_page. So the warning is unnecessary. Reported-by: Joey Liao Signed-off-by: Shaohua Li --- drivers/md/raid5.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 8ab8b65e1741..e48c262ce032 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -3502,8 +3502,6 @@ returnbi: dev = &sh->dev[i]; } else if (test_bit(R5_Discard, &dev->flags)) discard_pending = 1; - WARN_ON(test_bit(R5_SkipCopy, &dev->flags)); - WARN_ON(dev->page != dev->orig_page); } r5l_stripe_write_finished(sh);