linux-kernel - [PATCH v5 8/8] md: check mddev->pers before calling md_set

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Date: Thu,  1 Feb 2024 14:34:04 +0800
From: linan666@...weicloud.com
To: song@...nel.org,
	neilb@...e.com,
	mariusz.tkaczyk@...ux.intel.com,
	shli@...com
Cc: linux-raid@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linan666@...weicloud.com,
	yukuai3@...wei.com,
	yi.zhang@...wei.com,
	houtao1@...wei.com,
	yangerkun@...wei.com
Subject: [PATCH v5 8/8] md: check mddev->pers before calling md_set_readonly()

From: Li Nan <linan122@...wei.com>

If 'mddev->pers' is NULL, there is nothing to do in md_set_readonly().
Except for md_ioctl(), the other two callers of md_set_readonly() have
already checked 'mddev->pers'. To simplify the code, move the check of
'mddev->pers' to the caller.

Signed-off-by: Li Nan <linan122@...wei.com>
---
 drivers/md/md.c | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 86becf0015f5..2976cf778df3 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -6412,6 +6412,7 @@ void md_stop(struct mddev *mddev)
 
 EXPORT_SYMBOL_GPL(md_stop);
 
+/* ensure 'mddev->pers' exist before calling md_set_readonly() */
 static int md_set_readonly(struct mddev *mddev, struct block_device *bdev)
 {
 	int err = 0;
@@ -6441,8 +6442,7 @@ static int md_set_readonly(struct mddev *mddev, struct block_device *bdev)
 	mddev_lock_nointr(mddev);
 
 	mutex_lock(&mddev->open_mutex);
-	if ((mddev->pers && atomic_read(&mddev->openers) > !!bdev) ||
-	    mddev->sync_thread ||
+	if (atomic_read(&mddev->openers) > !!bdev || mddev->sync_thread ||
 	    test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) {
 		pr_warn("md: %s still in use.\n",mdname(mddev));
 		if (did_freeze) {
@@ -6453,20 +6453,18 @@ static int md_set_readonly(struct mddev *mddev, struct block_device *bdev)
 		err = -EBUSY;
 		goto out;
 	}
-	if (mddev->pers) {
-		__md_stop_writes(mddev);
+	__md_stop_writes(mddev);
 
-		err  = -ENXIO;
-		if (mddev->ro == MD_RDONLY)
-			goto out;
-		mddev->ro = MD_RDONLY;
-		set_disk_ro(mddev->gendisk, 1);
-		clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
-		set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
-		md_wakeup_thread(mddev->thread);
-		sysfs_notify_dirent_safe(mddev->sysfs_state);
-		err = 0;
-	}
+	err  = -ENXIO;
+	if (mddev->ro == MD_RDONLY)
+		goto out;
+	mddev->ro = MD_RDONLY;
+	set_disk_ro(mddev->gendisk, 1);
+	clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);
+	set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+	md_wakeup_thread(mddev->thread);
+	sysfs_notify_dirent_safe(mddev->sysfs_state);
+	err = 0;
 out:
 	mutex_unlock(&mddev->open_mutex);
 	return err;
@@ -7766,7 +7764,8 @@ static int md_ioctl(struct block_device *bdev, blk_mode_t mode,
 		goto unlock;
 
 	case STOP_ARRAY_RO:
-		err = md_set_readonly(mddev, bdev);
+		if (mddev->pers)
+			err = md_set_readonly(mddev, bdev);
 		goto unlock;
 
 	case HOT_REMOVE_DISK:
-- 
2.39.2