linux-kernel - [PATCH -next 3/7] md: don't rely on 'mddev->pers' to be set in mddev

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Message-Id: <20230803132751.2741652-4-yukuai1@huaweicloud.com>
Date:   Thu,  3 Aug 2023 21:27:47 +0800
From:   Yu Kuai <yukuai1@...weicloud.com>
To:     song@...nel.org, xni@...hat.com
Cc:     linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org,
        yukuai3@...wei.com, yukuai1@...weicloud.com, yi.zhang@...wei.com,
        yangerkun@...wei.com
Subject: [PATCH -next 3/7] md: don't rely on 'mddev->pers' to be set in mddev_suspend()

From: Yu Kuai <yukuai3@...wei.com>

Now that active io is initialized when mddev is allocated, it's safe to
call mddev_suspend() before 'mddev->pers' is set.

This also prevent null-ptr-def in some cases that caller doesn't
guarantee 'mddev->pers' to be set.

Signed-off-by: Yu Kuai <yukuai3@...wei.com>
---
 drivers/md/md.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 897e94a9e47d..f14f2f0a9484 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -448,7 +448,7 @@ void mddev_suspend(struct mddev *mddev)
 	set_bit(MD_ALLOW_SB_UPDATE, &mddev->flags);
 	percpu_ref_kill(&mddev->active_io);
 
-	if (mddev->pers->prepare_suspend)
+	if (mddev->pers && mddev->pers->prepare_suspend)
 		mddev->pers->prepare_suspend(mddev);
 
 	wait_event(mddev->sb_wait, percpu_ref_is_zero(&mddev->active_io));
-- 
2.39.2