diff --git a/sys/dev/sfxge/common/ef10_impl.h b/sys/dev/sfxge/common/ef10_impl.h
index 268af54990c..427fb45472f 100644
--- a/sys/dev/sfxge/common/ef10_impl.h
+++ b/sys/dev/sfxge/common/ef10_impl.h
@@ -296,11 +296,11 @@ ef10_mcdi_fini(
 
 extern			void
 ef10_mcdi_send_request(
-	__in		efx_nic_t *enp,
-	__in		void *hdrp,
-	__in		size_t hdr_len,
-	__in		void *sdup,
-	__in		size_t sdu_len);
+	__in			efx_nic_t *enp,
+	__in_bcount(hdr_len)	void *hdrp,
+	__in			size_t hdr_len,
+	__in_bcount(sdu_len)	void *sdup,
+	__in			size_t sdu_len);
 
 extern	__checkReturn	boolean_t
 ef10_mcdi_poll_response(
diff --git a/sys/dev/sfxge/common/ef10_mcdi.c b/sys/dev/sfxge/common/ef10_mcdi.c
index f14d35f08e9..22df04048ad 100644
--- a/sys/dev/sfxge/common/ef10_mcdi.c
+++ b/sys/dev/sfxge/common/ef10_mcdi.c
@@ -110,11 +110,11 @@ ef10_mcdi_fini(
 
 			void
 ef10_mcdi_send_request(
-	__in		efx_nic_t *enp,
-	__in		void *hdrp,
-	__in		size_t hdr_len,
-	__in		void *sdup,
-	__in		size_t sdu_len)
+	__in			efx_nic_t *enp,
+	__in_bcount(hdr_len)	void *hdrp,
+	__in			size_t hdr_len,
+	__in_bcount(sdu_len)	void *sdup,
+	__in			size_t sdu_len)
 {
 	const efx_mcdi_transport_t *emtp = enp->en_mcdi.em_emtp;
 	efsys_mem_t *esmp = emtp->emt_dma_mem;
diff --git a/sys/dev/sfxge/common/siena_impl.h b/sys/dev/sfxge/common/siena_impl.h
index eab8c73c938..83553e7f1ff 100644
--- a/sys/dev/sfxge/common/siena_impl.h
+++ b/sys/dev/sfxge/common/siena_impl.h
@@ -96,11 +96,11 @@ siena_mcdi_init(
 
 extern			void
 siena_mcdi_send_request(
-	__in		efx_nic_t *enp,
-	__in		void *hdrp,
-	__in		size_t hdr_len,
-	__in		void *sdup,
-	__in		size_t sdu_len);
+	__in			efx_nic_t *enp,
+	__in_bcount(hdr_len)	void *hdrp,
+	__in			size_t hdr_len,
+	__in_bcount(sdu_len)	void *sdup,
+	__in			size_t sdu_len);
 
 extern	__checkReturn	boolean_t
 siena_mcdi_poll_response(
diff --git a/sys/dev/sfxge/common/siena_mcdi.c b/sys/dev/sfxge/common/siena_mcdi.c
index a9bc1ca1eeb..90db28ac0e4 100644
--- a/sys/dev/sfxge/common/siena_mcdi.c
+++ b/sys/dev/sfxge/common/siena_mcdi.c
@@ -54,11 +54,11 @@ __FBSDID("$FreeBSD$");
 
 			void
 siena_mcdi_send_request(
-	__in		efx_nic_t *enp,
-	__in		void *hdrp,
-	__in		size_t hdr_len,
-	__in		void *sdup,
-	__in		size_t sdu_len)
+	__in			efx_nic_t *enp,
+	__in_bcount(hdr_len)	void *hdrp,
+	__in			size_t hdr_len,
+	__in_bcount(sdu_len)	void *sdup,
+	__in			size_t sdu_len)
 {
 	efx_mcdi_iface_t *emip = &(enp->en_mcdi.em_emip);
 	efx_dword_t dword;