diff --git a/sys/dev/netif/iwm/if_iwm_scan.c b/sys/dev/netif/iwm/if_iwm_scan.c
--- a/sys/dev/netif/iwm/if_iwm_scan.c
+++ b/sys/dev/netif/iwm/if_iwm_scan.c
@@ -567,10 +567,10 @@
 		sc->last_ebs_successful);
 }
 
-static int
+static size_t
 iwm_scan_size(struct iwm_softc *sc)
 {
-	int base_size;
+	size_t base_size;
 
 	if (iwm_fw_has_capa(sc, IWM_UCODE_TLV_CAPA_UMAC_SCAN)) {
 		if (iwm_fw_has_api(sc, IWM_UCODE_TLV_API_ADAPTIVE_DWELL))