Index: head/sys/dev/e1000/if_em.c
===================================================================
--- head/sys/dev/e1000/if_em.c
+++ head/sys/dev/e1000/if_em.c
@@ -1270,14 +1270,7 @@
 	/* Setup Multicast table */
 	em_if_multi_set(ctx);
 
-	/*
-	 * Figure out the desired mbuf
-	 * pool for doing jumbos
-	 */
-	if (adapter->hw.mac.max_frame_size <= 2048)
-		adapter->rx_mbuf_sz = MCLBYTES;
-	else
-		adapter->rx_mbuf_sz = MJUMPAGESIZE;
+	adapter->rx_mbuf_sz = iflib_get_rx_mbuf_sz(ctx);
 	em_initialize_receive_unit(ctx);
 
 	/* Use real VLAN Filter support? */
Index: head/sys/dev/ixgbe/if_ix.c
===================================================================
--- head/sys/dev/ixgbe/if_ix.c
+++ head/sys/dev/ixgbe/if_ix.c
@@ -2880,10 +2880,7 @@
 	ixgbe_if_multi_set(ctx);
 
 	/* Determine the correct mbuf pool, based on frame size */
-	if (adapter->max_frame_size <= MCLBYTES)
-		adapter->rx_mbuf_sz = MCLBYTES;
-	else
-		adapter->rx_mbuf_sz = MJUMPAGESIZE;
+	adapter->rx_mbuf_sz = iflib_get_rx_mbuf_sz(ctx);
 
 	/* Configure RX settings */
 	ixgbe_initialize_receive_units(ctx);
Index: head/sys/dev/ixgbe/if_ixv.c
===================================================================
--- head/sys/dev/ixgbe/if_ixv.c
+++ head/sys/dev/ixgbe/if_ixv.c
@@ -629,14 +629,7 @@
 	/* Setup Multicast table */
 	ixv_if_multi_set(ctx);
 
-	/*
-	 * Determine the correct mbuf pool
-	 * for doing jumbo/headersplit
-	 */
-	if (ifp->if_mtu > ETHERMTU)
-		adapter->rx_mbuf_sz = MJUMPAGESIZE;
-	else
-		adapter->rx_mbuf_sz = MCLBYTES;
+	adapter->rx_mbuf_sz = iflib_get_rx_mbuf_sz(ctx);
 
 	/* Configure RX settings */
 	ixv_initialize_receive_units(ctx);
Index: head/sys/dev/ixl/if_iavf.c
===================================================================
--- head/sys/dev/ixl/if_iavf.c
+++ head/sys/dev/ixl/if_iavf.c
@@ -614,7 +614,6 @@
 static void
 iavf_init_queues(struct ixl_vsi *vsi)
 {
-	if_softc_ctx_t scctx = vsi->shared;
 	struct ixl_tx_queue *tx_que = vsi->tx_queues;
 	struct ixl_rx_queue *rx_que = vsi->rx_queues;
 	struct rx_ring *rxr;
@@ -625,10 +624,7 @@
 	for (int i = 0; i < vsi->num_rx_queues; i++, rx_que++) {
 		rxr = &rx_que->rxr;
 
-		if (scctx->isc_max_frame_size <= MCLBYTES)
-			rxr->mbuf_sz = MCLBYTES;
-		else
-			rxr->mbuf_sz = MJUMPAGESIZE;
+		rxr->mbuf_sz = iflib_get_rx_mbuf_sz(vsi->ctx);
 
 		wr32(vsi->hw, rxr->tail, 0);
 	}
Index: head/sys/dev/ixl/ixl_pf_main.c
===================================================================
--- head/sys/dev/ixl/ixl_pf_main.c
+++ head/sys/dev/ixl/ixl_pf_main.c
@@ -1300,10 +1300,7 @@
 		struct i40e_hmc_obj_rxq rctx;
 
 		/* Next setup the HMC RX Context  */
-		if (scctx->isc_max_frame_size <= MCLBYTES)
-			rxr->mbuf_sz = MCLBYTES;
-		else
-			rxr->mbuf_sz = MJUMPAGESIZE;
+		rxr->mbuf_sz = iflib_get_rx_mbuf_sz(vsi->ctx);
 
 		u16 max_rxmax = rxr->mbuf_sz * hw->func_caps.rx_buf_chain_len;
 
Index: head/sys/net/iflib.h
===================================================================
--- head/sys/net/iflib.h
+++ head/sys/net/iflib.h
@@ -381,6 +381,8 @@
 void iflib_request_reset(if_ctx_t ctx);
 uint8_t iflib_in_detach(if_ctx_t ctx);
 
+uint32_t iflib_get_rx_mbuf_sz(if_ctx_t ctx);
+
 /*
  * If the driver can plug cleanly in to newbus use these
  */
Index: head/sys/net/iflib.c
===================================================================
--- head/sys/net/iflib.c
+++ head/sys/net/iflib.c
@@ -171,6 +171,7 @@
 	uint32_t ifc_if_flags;
 	uint32_t ifc_flags;
 	uint32_t ifc_max_fl_buf_size;
+	uint32_t ifc_rx_mbuf_sz;
 
 	int ifc_link_state;
 	int ifc_link_irq;
@@ -2172,7 +2173,6 @@
 {
 	iflib_rxq_t rxq = fl->ifl_rxq;
 	if_ctx_t ctx = rxq->ifr_ctx;
-	if_softc_ctx_t sctx = &ctx->ifc_softc_ctx;
 
 	bit_nclear(fl->ifl_rx_bitmap, 0, fl->ifl_size - 1);
 	/*
@@ -2181,14 +2181,7 @@
 	iflib_fl_bufs_free(fl);
 	/* Now replenish the mbufs */
 	MPASS(fl->ifl_credits == 0);
-	/*
-	 * XXX don't set the max_frame_size to larger
-	 * than the hardware can handle
-	 */
-	if (sctx->isc_max_frame_size <= 2048)
-		fl->ifl_buf_size = MCLBYTES;
-	else
-		fl->ifl_buf_size = MJUMPAGESIZE;
+	fl->ifl_buf_size = ctx->ifc_rx_mbuf_sz;
 	if (fl->ifl_buf_size > ctx->ifc_max_fl_buf_size)
 		ctx->ifc_max_fl_buf_size = fl->ifl_buf_size;
 	fl->ifl_cltype = m_gettype(fl->ifl_buf_size);
@@ -2314,6 +2307,27 @@
 }
 
 static void
+iflib_calc_rx_mbuf_sz(if_ctx_t ctx)
+{
+	if_softc_ctx_t sctx = &ctx->ifc_softc_ctx;
+
+	/*
+	 * XXX don't set the max_frame_size to larger
+	 * than the hardware can handle
+	 */
+	if (sctx->isc_max_frame_size <= MCLBYTES)
+		ctx->ifc_rx_mbuf_sz = MCLBYTES;
+	else
+		ctx->ifc_rx_mbuf_sz = MJUMPAGESIZE;
+}
+
+uint32_t
+iflib_get_rx_mbuf_sz(if_ctx_t ctx)
+{
+	return (ctx->ifc_rx_mbuf_sz);
+}
+
+static void
 iflib_init_locked(if_ctx_t ctx)
 {
 	if_softc_ctx_t sctx = &ctx->ifc_softc_ctx;
@@ -2347,6 +2361,14 @@
 		CALLOUT_UNLOCK(txq);
 		iflib_netmap_txq_init(ctx, txq);
 	}
+
+	/*
+	 * Calculate a suitable Rx mbuf size prior to calling IFDI_INIT, so
+	 * that drivers can use the value when setting up the hardware receive
+	 * buffers.
+	 */
+	iflib_calc_rx_mbuf_sz(ctx);
+
 #ifdef INVARIANTS
 	i = if_getdrvflags(ifp);
 #endif
Index: head/sys/sys/param.h
===================================================================
--- head/sys/sys/param.h
+++ head/sys/sys/param.h
@@ -60,7 +60,7 @@
  *		in the range 5 to 9.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1300016	/* Master, propagated to newvers */
+#define __FreeBSD_version 1300017	/* Master, propagated to newvers */
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,