Re: [PATCH] md: get rdev->mddev with READ_ONCE()
From: Yu Kuai <hidden>
Date: 2024-01-02 06:16:44
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在 2023/12/29 15:05, Li Lingfeng 写道:
From: Li Lingfeng <redacted> Users may get rdev->mddev by sysfs while rdev is releasing. So use both READ_ONCE() and WRITE_ONCE() to prevent load/store tearing and to read/write mddev atomically.
LGTM Reviewed-by: Yu Kuai <redacted>
quoted hunk ↗ jump to hunk
Signed-off-by: Li Lingfeng <redacted> --- drivers/md/md.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/drivers/md/md.c b/drivers/md/md.c index 9bdd57324c37..3b38a565bffa 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c@@ -2562,7 +2562,7 @@ static void md_kick_rdev_from_array(struct md_rdev *rdev) list_del_rcu(&rdev->same_set); pr_debug("md: unbind<%pg>\n", rdev->bdev); mddev_destroy_serial_pool(rdev->mddev, rdev); - rdev->mddev = NULL; + WRITE_ONCE(rdev->mddev, NULL); sysfs_remove_link(&rdev->kobj, "block"); sysfs_put(rdev->sysfs_state); sysfs_put(rdev->sysfs_unack_badblocks);@@ -3646,7 +3646,7 @@ rdev_attr_store(struct kobject *kobj, struct attribute *attr, struct kernfs_node *kn = NULL; bool suspend = false; ssize_t rv; - struct mddev *mddev = rdev->mddev; + struct mddev *mddev = READ_ONCE(rdev->mddev); if (!entry->store) return -EIO;