Index: if_em.c
===================================================================
RCS file: /cvs/src/sys/dev/pci/if_em.c,v
retrieving revision 1.308
diff -u -p -r1.308 if_em.c
--- if_em.c	8 Oct 2015 09:21:26 -0000	1.308
+++ if_em.c	9 Oct 2015 05:01:22 -0000
@@ -229,7 +229,7 @@ void em_disable_aspm(struct em_softc *);
 void em_txeof(struct em_softc *);
 int  em_allocate_receive_structures(struct em_softc *);
 int  em_allocate_transmit_structures(struct em_softc *);
-int  em_rxfill(struct em_softc *);
+int  em_rxfill(struct em_softc *, int);
 void em_rxeof(struct em_softc *);
 void em_receive_checksum(struct em_softc *, struct em_rx_desc *,
 			 struct mbuf *);
@@ -240,7 +240,7 @@ void em_iff(struct em_softc *);
 void em_print_hw_stats(struct em_softc *);
 #endif
 void em_update_link_status(struct em_softc *);
-int  em_get_buf(struct em_softc *, int);
+int  em_get_buf(struct em_softc *, int, int);
 void em_enable_hw_vlans(struct em_softc *);
 int  em_encap(struct em_softc *, struct mbuf *);
 void em_smartspeed(struct em_softc *);
@@ -931,7 +931,7 @@ em_intr(void *arg)
 		KERNEL_UNLOCK();
 	}
 
-	if (refill && em_rxfill(sc)) {
+	if (refill && em_rxfill(sc, 0)) {
 		/* Advance the Rx Queue #0 "Tail Pointer". */
 		E1000_WRITE_REG(&sc->hw, RDT, sc->last_rx_desc_filled);
 	}
@@ -2499,7 +2499,7 @@ em_txeof(struct em_softc *sc)
  *
  **********************************************************************/
 int
-em_get_buf(struct em_softc *sc, int i)
+em_get_buf(struct em_softc *sc, int i, int wait)
 {
 	struct mbuf    *m;
 	struct em_buffer *pkt;
@@ -2515,7 +2515,7 @@ em_get_buf(struct em_softc *sc, int i)
 		return (ENOBUFS);
 	}
 
-	m = MCLGETI(NULL, M_DONTWAIT, NULL, EM_MCLBYTES);
+	m = MCLGETI(NULL, wait ? M_WAITOK : M_NOWAIT, NULL, EM_MCLBYTES);
 	if (!m) {
 		sc->mbuf_cluster_failed++;
 		return (ENOBUFS);
@@ -2525,7 +2525,8 @@ em_get_buf(struct em_softc *sc, int i)
 	m_adj(m, ETHER_ALIGN);
 #endif
 
-	error = bus_dmamap_load_mbuf(sc->rxtag, pkt->map, m, BUS_DMA_NOWAIT);
+	error = bus_dmamap_load_mbuf(sc->rxtag, pkt->map, m,
+	    wait ? BUS_DMA_WAITOK : BUS_DMA_NOWAIT);
 	if (error) {
 		m_freem(m);
 		return (error);
@@ -2617,7 +2618,7 @@ em_setup_receive_structures(struct em_so
 	lwm = max(4, 2 * ((ifp->if_hardmtu / MCLBYTES) + 1));
 	if_rxr_init(&sc->rx_ring, lwm, sc->num_rx_desc);
 
-	if (em_rxfill(sc) == 0) {
+	if (em_rxfill(sc, 1) == 0) {
 		printf("%s: unable to fill any rx descriptors\n",
 		    sc->sc_dv.dv_xname);
 	}
@@ -2773,7 +2774,7 @@ em_free_receive_structures(struct em_sof
 }
 
 int
-em_rxfill(struct em_softc *sc)
+em_rxfill(struct em_softc *sc, int wait)
 {
 	u_int slots;
 	int post = 0;
@@ -2786,7 +2787,7 @@ em_rxfill(struct em_softc *sc)
 		if (++i == sc->num_rx_desc)
 			i = 0;
 
-		if (em_get_buf(sc, i) != 0)
+		if (em_get_buf(sc, i, wait) != 0)
 			break;
 
 		sc->last_rx_desc_filled = i;