1 files changed, 42 insertions, 30 deletions

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 6eeaab77fbe0..5b18f5f33dfa 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -857,46 +857,53 @@ static void axienet_recv(struct net_device *ndev)
 	while ((cur_p->status & XAXIDMA_BD_STS_COMPLETE_MASK)) {
 		dma_addr_t phys;
 
-		tail_p = lp->rx_bd_p + sizeof(*lp->rx_bd_v) * lp->rx_bd_ci;
-
 		/* Ensure we see complete descriptor update */
 		dma_rmb();
-		phys = desc_get_phys_addr(lp, cur_p);
-		dma_unmap_single(ndev->dev.parent, phys, lp->max_frm_size,
-				 DMA_FROM_DEVICE);
 
 		skb = cur_p->skb;
 		cur_p->skb = NULL;
-		length = cur_p->app4 & 0x0000FFFF;
-
-		skb_put(skb, length);
-		skb->protocol = eth_type_trans(skb, ndev);
-		/*skb_checksum_none_assert(skb);*/
-		skb->ip_summed = CHECKSUM_NONE;
-
-		/* if we're doing Rx csum offload, set it up */
-		if (lp->features & XAE_FEATURE_FULL_RX_CSUM) {
-			csumstatus = (cur_p->app2 &
-				      XAE_FULL_CSUM_STATUS_MASK) >> 3;
-			if ((csumstatus == XAE_IP_TCP_CSUM_VALIDATED) ||
-			    (csumstatus == XAE_IP_UDP_CSUM_VALIDATED)) {
-				skb->ip_summed = CHECKSUM_UNNECESSARY;
+
+		/* skb could be NULL if a previous pass already received the
+		 * packet for this slot in the ring, but failed to refill it
+		 * with a newly allocated buffer. In this case, don't try to
+		 * receive it again.
+		 */
+		if (likely(skb)) {
+			length = cur_p->app4 & 0x0000FFFF;
+
+			phys = desc_get_phys_addr(lp, cur_p);
+			dma_unmap_single(ndev->dev.parent, phys, lp->max_frm_size,
+					 DMA_FROM_DEVICE);
+
+			skb_put(skb, length);
+			skb->protocol = eth_type_trans(skb, ndev);
+			/*skb_checksum_none_assert(skb);*/
+			skb->ip_summed = CHECKSUM_NONE;
+
+			/* if we're doing Rx csum offload, set it up */
+			if (lp->features & XAE_FEATURE_FULL_RX_CSUM) {
+				csumstatus = (cur_p->app2 &
+					      XAE_FULL_CSUM_STATUS_MASK) >> 3;
+				if (csumstatus == XAE_IP_TCP_CSUM_VALIDATED ||
+				    csumstatus == XAE_IP_UDP_CSUM_VALIDATED) {
+					skb->ip_summed = CHECKSUM_UNNECESSARY;
+				}
+			} else if ((lp->features & XAE_FEATURE_PARTIAL_RX_CSUM) != 0 &&
+				   skb->protocol == htons(ETH_P_IP) &&
+				   skb->len > 64) {
+				skb->csum = be32_to_cpu(cur_p->app3 & 0xFFFF);
+				skb->ip_summed = CHECKSUM_COMPLETE;
 			}
-		} else if ((lp->features & XAE_FEATURE_PARTIAL_RX_CSUM) != 0 &&
-			   skb->protocol == htons(ETH_P_IP) &&
-			   skb->len > 64) {
-			skb->csum = be32_to_cpu(cur_p->app3 & 0xFFFF);
-			skb->ip_summed = CHECKSUM_COMPLETE;
-		}
 
-		netif_rx(skb);
+			netif_rx(skb);
 
-		size += length;
-		packets++;
+			size += length;
+			packets++;
+		}
 
 		new_skb = netdev_alloc_skb_ip_align(ndev, lp->max_frm_size);
 		if (!new_skb)
-			return;
+			break;
 
 		phys = dma_map_single(ndev->dev.parent, new_skb->data,
 				      lp->max_frm_size,
@@ -905,7 +912,7 @@ static void axienet_recv(struct net_device *ndev)
 			if (net_ratelimit())
 				netdev_err(ndev, "RX DMA mapping error\n");
 			dev_kfree_skb(new_skb);
-			return;
+			break;
 		}
 		desc_set_phys_addr(lp, phys, cur_p);
 
@@ -913,6 +920,11 @@ static void axienet_recv(struct net_device *ndev)
 		cur_p->status = 0;
 		cur_p->skb = new_skb;
 
+		/* Only update tail_p to mark this slot as usable after it has
+		 * been successfully refilled.
+		 */
+		tail_p = lp->rx_bd_p + sizeof(*lp->rx_bd_v) * lp->rx_bd_ci;
+
 		if (++lp->rx_bd_ci >= lp->rx_bd_num)
 			lp->rx_bd_ci = 0;
 		cur_p = &lp->rx_bd_v[lp->rx_bd_ci];