use the newer and more pleasant kstrtoull() to replace simple_strtoull(),
because simple_strtoull() is marked for obsoletion.
Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
Signed-off-by: Chris Mason <clm@fb.com>
        sizestr = vol_args->name;
        devstr = strchr(sizestr, ':');
        if (devstr) {
-               char *end;
                sizestr = devstr + 1;
                *devstr = '\0';
                devstr = vol_args->name;
-               devid = simple_strtoull(devstr, &end, 10);
+               ret = kstrtoull(devstr, 10, &devid);
+               if (ret)
+                       goto out_free;
                if (!devid) {
                        ret = -EINVAL;
                        goto out_free;