md/r5cache: move mddev_lock() out of r5c_journal_mode_set()

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@vger.kernel.org (v4.13+)
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>

diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index f1c86d938502e61c93d8951680767f1af5de98e5..39f31f07ffe9ece14d9764f0eb511ea00f812618 100644 (file)
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -2577,31 +2577,22 @@ static ssize_t r5c_journal_mode_show(struct mddev *mddev, char *page)
 int r5c_journal_mode_set(struct mddev *mddev, int mode)
 {
        struct r5conf *conf;
-       int err;
 
        if (mode < R5C_JOURNAL_MODE_WRITE_THROUGH ||
            mode > R5C_JOURNAL_MODE_WRITE_BACK)
                return -EINVAL;
 
-       err = mddev_lock(mddev);
-       if (err)
-               return err;
        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 +2605,7 @@ 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 +2617,12 @@ 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;
+       ret = mddev_lock(mddev);
+       if (ret)
+               return ret;
+       ret = r5c_journal_mode_set(mddev, mode);
+       mddev_unlock(mddev);
+       return ret ?: length;
 }
 
 struct md_sysfs_entry