diff --git a/sys/cam/ata/ata_xpt.c b/sys/cam/ata/ata_xpt.c
index 60c6d6951de9..559e9a234b87 100644
--- a/sys/cam/ata/ata_xpt.c
+++ b/sys/cam/ata/ata_xpt.c
@@ -270,7 +270,7 @@ CAM_XPT_PROTO(ata_proto_satapm);
 CAM_XPT_PROTO(ata_proto_semb);
 
 static void
-aprobe_periph_init()
+aprobe_periph_init(void)
 {
 }
 
diff --git a/sys/cam/cam_xpt.c b/sys/cam/cam_xpt.c
index e8f02239da72..cb837302208e 100644
--- a/sys/cam/cam_xpt.c
+++ b/sys/cam/cam_xpt.c
@@ -354,7 +354,7 @@ device_is_queued(struct cam_ed *device)
 }
 
 static void
-xpt_periph_init()
+xpt_periph_init(void)
 {
 	make_dev(&xpt_cdevsw, 0, UID_ROOT, GID_OPERATOR, 0600, "xpt0");
 }
@@ -4669,7 +4669,7 @@ xpt_done_direct(union ccb *done_ccb)
 }
 
 union ccb *
-xpt_alloc_ccb()
+xpt_alloc_ccb(void)
 {
 	union ccb *new_ccb;
 
@@ -4678,7 +4678,7 @@ xpt_alloc_ccb()
 }
 
 union ccb *
-xpt_alloc_ccb_nowait()
+xpt_alloc_ccb_nowait(void)
 {
 	union ccb *new_ccb;
 
diff --git a/sys/cam/mmc/mmc_xpt.c b/sys/cam/mmc/mmc_xpt.c
index f70dbec5ee49..b4ea0968d135 100644
--- a/sys/cam/mmc/mmc_xpt.c
+++ b/sys/cam/mmc/mmc_xpt.c
@@ -467,7 +467,7 @@ PERIPHDRIVER_DECLARE(mmcprobe, probe_driver);
 #define	CARD_ID_FREQUENCY 400000 /* Spec requires 400kHz max during ID phase. */
 
 static void
-probe_periph_init()
+probe_periph_init(void)
 {
 }
 
diff --git a/sys/cam/nvme/nvme_xpt.c b/sys/cam/nvme/nvme_xpt.c
index 2c3491a6a5d8..687da220325a 100644
--- a/sys/cam/nvme/nvme_xpt.c
+++ b/sys/cam/nvme/nvme_xpt.c
@@ -192,9 +192,8 @@ static struct xpt_proto nvme_proto = {
 CAM_XPT_PROTO(nvme_proto);
 
 static void
-nvme_probe_periph_init()
+nvme_probe_periph_init(void)
 {
-
 }
 
 static cam_status
diff --git a/sys/cam/scsi/scsi_targ_bh.c b/sys/cam/scsi/scsi_targ_bh.c
index 4dad7153e1d6..f0c7a9b6ae68 100644
--- a/sys/cam/scsi/scsi_targ_bh.c
+++ b/sys/cam/scsi/scsi_targ_bh.c
@@ -737,7 +737,7 @@ targbherror(union ccb *ccb, u_int32_t cam_flags, u_int32_t sense_flags)
 #endif
 
 static struct targbh_cmd_desc*
-targbhallocdescr()
+targbhallocdescr(void)
 {
 	struct targbh_cmd_desc* descr;
 
diff --git a/sys/cam/scsi/scsi_xpt.c b/sys/cam/scsi/scsi_xpt.c
index c3c23f573425..2a744b3e520b 100644
--- a/sys/cam/scsi/scsi_xpt.c
+++ b/sys/cam/scsi/scsi_xpt.c
@@ -649,7 +649,7 @@ static struct xpt_proto scsi_proto = {
 CAM_XPT_PROTO(scsi_proto);
 
 static void
-probe_periph_init()
+probe_periph_init(void)
 {
 }