[PATCH] bcache: use kmemdup_nul for CACHED_LABEL buffer

[Geliang Tang]

This patch uses kmemdup_nul to create a NUL-terminated string from
dc->sb.label. This is better than open coding it.

With this, we can move env[2] initialization into env[] array to make
code more elegant.

Signed-off-by: Geliang Tang <geliangt...@gmail.com>
---
 drivers/md/bcache/super.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 4dee119c3664..84ab241c8516 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -906,21 +906,18 @@ static int cached_dev_status_update(void *arg)
 void bch_cached_dev_run(struct cached_dev *dc)
 {
        struct bcache_device *d = &dc->disk;
-       char buf[SB_LABEL_SIZE + 1];
+       char *buf = kmemdup_nul(dc->sb.label, SB_LABEL_SIZE, GFP_KERNEL);
        char *env[] = {
                "DRIVER=bcache",
                kasprintf(GFP_KERNEL, "CACHED_UUID=%pU", dc->sb.uuid),
-               NULL,
+               kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf ? : ""),
                NULL,
        };
 
-       memcpy(buf, dc->sb.label, SB_LABEL_SIZE);
-       buf[SB_LABEL_SIZE] = '\0';
-       env[2] = kasprintf(GFP_KERNEL, "CACHED_LABEL=%s", buf);
-
        if (atomic_xchg(&dc->running, 1)) {
                kfree(env[1]);
                kfree(env[2]);
+               kfree(buf);
                return;
        }
 
@@ -944,6 +941,7 @@ void bch_cached_dev_run(struct cached_dev *dc)
        kobject_uevent_env(&disk_to_dev(d->disk)->kobj, KOBJ_CHANGE, env);
        kfree(env[1]);
        kfree(env[2]);
+       kfree(buf);
 
        if (sysfs_create_link(&d->kobj, &disk_to_dev(d->disk)->kobj, "dev") ||
            sysfs_create_link(&disk_to_dev(d->disk)->kobj, &d->kobj, "bcache"))
-- 
2.17.1