The driver uses test_facility(), but does not include the corresponding include file explicitly. The driver currently builds only thanks to the following include chain: vfio_ap_drv.c <linux/module.h> <linux/elf.h> <asm/elf.h> <linux/compat.h> <asm/uaccess.h> <asm/facility.h> Files should not rely on such fragile implicit includes. Signed-off-by: Petr Tesarik <ptesarik@xxxxxxxx> --- drivers/s390/crypto/vfio_ap_drv.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/s390/crypto/vfio_ap_drv.c b/drivers/s390/crypto/vfio_ap_drv.c index 7667b38728f0..31c6c847eaca 100644 --- a/drivers/s390/crypto/vfio_ap_drv.c +++ b/drivers/s390/crypto/vfio_ap_drv.c @@ -11,6 +11,7 @@ #include <linux/mod_devicetable.h> #include <linux/slab.h> #include <linux/string.h> +#include <asm/facility.h> #include "vfio_ap_private.h" #define VFIO_AP_ROOT_NAME "vfio_ap" -- 2.16.4