On Fri, Nov 17, 2017 at 05:23:11PM -0800, Song Liu wrote:
> r5c_journal_mode_set() is called by r5c_journal_mode_store() and
> raid_ctr() in dm-raid. We don't need mddev_lock() when calling from
> raid_ctr(). This patch fixes this by moves the mddev_lock() to
> r5c_journal_mode_store().
>
> Cc: stable@xxxxxxxxxxxxxxx (v4.13+)
> Signed-off-by: Song Liu <songliubraving@xxxxxx>
> ---
> drivers/md/raid5-cache.c | 17 +++++++----------
> 1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
> index f1c86d9..e01f229 100644
> --- a/drivers/md/raid5-cache.c
> +++ b/drivers/md/raid5-cache.c
> @@ -2583,25 +2583,19 @@ int r5c_journal_mode_set(struct mddev *mddev, int mode)
> mode > R5C_JOURNAL_MODE_WRITE_BACK)
> return -EINVAL;
>
> - err = mddev_lock(mddev);
> if (err)
> return err;
please make sure your code doesn't have compiling warnning. The 'err' is an
obvious 'use before initialization' warnning.
> conf = mddev->private;
> - if (!conf || !conf->log) {
> - mddev_unlock(mddev);
> + if (!conf || !conf->log)
> return -ENODEV;
> - }
>
> if (raid5_calc_degraded(conf) > 0 &&
> - mode == R5C_JOURNAL_MODE_WRITE_BACK) {
> - mddev_unlock(mddev);
> + mode == R5C_JOURNAL_MODE_WRITE_BACK)
> return -EINVAL;
> - }
>
> mddev_suspend(mddev);
> conf->log->r5c_journal_mode = mode;
> mddev_resume(mddev);
> - mddev_unlock(mddev);
>
> pr_debug("md/raid:%s: setting r5c cache mode to %d: %s\n",
> mdname(mddev), mode, r5c_journal_mode_str[mode]);
> @@ -2614,6 +2608,7 @@ static ssize_t r5c_journal_mode_store(struct mddev *mddev,
> {
> int mode = ARRAY_SIZE(r5c_journal_mode_str);
> size_t len = length;
> + int ret;
>
> if (len < 2)
> return -EINVAL;
> @@ -2625,8 +2620,10 @@ static ssize_t r5c_journal_mode_store(struct mddev *mddev,
> if (strlen(r5c_journal_mode_str[mode]) == len &&
> !strncmp(page, r5c_journal_mode_str[mode], len))
> break;
> -
> - return r5c_journal_mode_set(mddev, mode) ?: length;
> + mddev_lock(mddev);
and you don't check return value for mddev_lock, which has __must_check marked.
> + ret = r5c_journal_mode_set(mddev, mode);
> + mddev_unlock(mddev);
> + return ret ?: length;
> }
>
> struct md_sysfs_entry
> --
> 2.9.5
>