s390/ipl: Fix never less than zero warning

DEFINE_IPL_ATTR_STR_RW() macro produces "unsigned 'len' is never less
than zero." warning when sys_vmcmd_on_*_store() callbacks are defined.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202412081614.5uel8F6W-lkp@intel.com/
Fixes: 247576bf624a ("s390/ipl: Do not accept z/VM CP diag X'008' cmds longer than max length")
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index edbb52ce3f1ec23d8e464fce3fddee64d2327848..7d12a1305fc99f0777fadfc5e5b3c127d97fee79 100644 (file)
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -270,7 +270,7 @@ static ssize_t sys_##_prefix##_##_name##_store(struct kobject *kobj,        \
        if (len >= sizeof(_value))                                      \
                return -E2BIG;                                          \
        len = strscpy(_value, buf, sizeof(_value));                     \
-       if (len < 0)                                                    \
+       if ((ssize_t)len < 0)                                           \
                return len;                                             \
        strim(_value);                                                  \
        return len;                                                     \