ixgbe: add LRO support

Support for in-kernel LRO with the ability to enable/disable via ethtool
based on comments from Ben Hutchings.

Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakala@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: PJ Waskiewicz <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/ixgbe/ixgbe_main.c b/drivers/net/ixgbe/ixgbe_main.c
index 0d37c90..f429c9a 100644
--- a/drivers/net/ixgbe/ixgbe_main.c
+++ b/drivers/net/ixgbe/ixgbe_main.c
@@ -389,24 +389,39 @@
  * ixgbe_receive_skb - Send a completed packet up the stack
  * @adapter: board private structure
  * @skb: packet to send up
- * @is_vlan: packet has a VLAN tag
- * @tag: VLAN tag from descriptor
+ * @status: hardware indication of status of receive
+ * @rx_ring: rx descriptor ring (for a specific queue) to setup
+ * @rx_desc: rx descriptor
  **/
 static void ixgbe_receive_skb(struct ixgbe_adapter *adapter,
-			      struct sk_buff *skb, bool is_vlan,
-			      u16 tag)
+			      struct sk_buff *skb, u8 status,
+			      struct ixgbe_ring *ring,
+                              union ixgbe_adv_rx_desc *rx_desc)
 {
-	if (!(adapter->flags & IXGBE_FLAG_IN_NETPOLL)) {
-		if (adapter->vlgrp && is_vlan)
-			vlan_hwaccel_receive_skb(skb, adapter->vlgrp, tag);
-		else
-			netif_receive_skb(skb);
-	} else {
+	bool is_vlan = (status & IXGBE_RXD_STAT_VP);
+	u16 tag = le16_to_cpu(rx_desc->wb.upper.vlan);
 
+	if (adapter->netdev->features & NETIF_F_LRO &&
+	    skb->ip_summed == CHECKSUM_UNNECESSARY) {
 		if (adapter->vlgrp && is_vlan)
-			vlan_hwaccel_rx(skb, adapter->vlgrp, tag);
+			lro_vlan_hwaccel_receive_skb(&ring->lro_mgr, skb,
+			                             adapter->vlgrp, tag,
+			                             rx_desc);
 		else
-			netif_rx(skb);
+			lro_receive_skb(&ring->lro_mgr, skb, rx_desc);
+		ring->lro_used = true;
+	} else {
+		if (!(adapter->flags & IXGBE_FLAG_IN_NETPOLL)) {
+			if (adapter->vlgrp && is_vlan)
+				vlan_hwaccel_receive_skb(skb, adapter->vlgrp, tag);
+			else
+				netif_receive_skb(skb);
+		} else {
+			if (adapter->vlgrp && is_vlan)
+				vlan_hwaccel_rx(skb, adapter->vlgrp, tag);
+			else
+				netif_rx(skb);
+		}
 	}
 }
 
@@ -546,8 +561,8 @@
 	struct sk_buff *skb;
 	unsigned int i;
 	u32 upper_len, len, staterr;
-	u16 hdr_info, vlan_tag;
-	bool is_vlan, cleaned = false;
+	u16 hdr_info;
+	bool cleaned = false;
 	int cleaned_count = 0;
 	unsigned int total_rx_bytes = 0, total_rx_packets = 0;
 
@@ -556,8 +571,6 @@
 	rx_desc = IXGBE_RX_DESC_ADV(*rx_ring, i);
 	staterr = le32_to_cpu(rx_desc->wb.upper.status_error);
 	rx_buffer_info = &rx_ring->rx_buffer_info[i];
-	is_vlan = (staterr & IXGBE_RXD_STAT_VP);
-	vlan_tag = le16_to_cpu(rx_desc->wb.upper.vlan);
 
 	while (staterr & IXGBE_RXD_STAT_DD) {
 		if (*work_done >= work_to_do)
@@ -635,7 +648,7 @@
 		total_rx_packets++;
 
 		skb->protocol = eth_type_trans(skb, netdev);
-		ixgbe_receive_skb(adapter, skb, is_vlan, vlan_tag);
+		ixgbe_receive_skb(adapter, skb, staterr, rx_ring, rx_desc);
 		netdev->last_rx = jiffies;
 
 next_desc:
@@ -652,8 +665,11 @@
 		rx_buffer_info = next_buffer;
 
 		staterr = le32_to_cpu(rx_desc->wb.upper.status_error);
-		is_vlan = (staterr & IXGBE_RXD_STAT_VP);
-		vlan_tag = le16_to_cpu(rx_desc->wb.upper.vlan);
+	}
+
+	if (rx_ring->lro_used) {
+		lro_flush_all(&rx_ring->lro_mgr);
+		rx_ring->lro_used = false;
 	}
 
 	rx_ring->next_to_clean = i;
@@ -1382,6 +1398,33 @@
 
 #define IXGBE_SRRCTL_BSIZEHDRSIZE_SHIFT			2
 /**
+ * ixgbe_get_skb_hdr - helper function for LRO header processing
+ * @skb: pointer to sk_buff to be added to LRO packet
+ * @iphdr: pointer to tcp header structure
+ * @tcph: pointer to tcp header structure
+ * @hdr_flags: pointer to header flags
+ * @priv: private data
+ **/
+static int ixgbe_get_skb_hdr(struct sk_buff *skb, void **iphdr, void **tcph,
+                             u64 *hdr_flags, void *priv)
+{
+	union ixgbe_adv_rx_desc *rx_desc = priv;
+
+	/* Verify that this is a valid IPv4 TCP packet */
+	if (!(rx_desc->wb.lower.lo_dword.pkt_info &
+	    (IXGBE_RXDADV_PKTTYPE_IPV4 | IXGBE_RXDADV_PKTTYPE_TCP)))
+		return -1;
+
+	/* Set network headers */
+	skb_reset_network_header(skb);
+	skb_set_transport_header(skb, ip_hdrlen(skb));
+	*iphdr = ip_hdr(skb);
+	*tcph = tcp_hdr(skb);
+	*hdr_flags = LRO_IPV4 | LRO_TCP;
+	return 0;
+}
+
+/**
  * ixgbe_configure_rx - Configure 8254x Receive Unit after Reset
  * @adapter: board private structure
  *
@@ -1470,6 +1513,17 @@
 		adapter->rx_ring[i].tail = IXGBE_RDT(i);
 	}
 
+	/* Intitial LRO Settings */
+	adapter->rx_ring[i].lro_mgr.max_aggr = IXGBE_MAX_LRO_AGGREGATE;
+	adapter->rx_ring[i].lro_mgr.max_desc = IXGBE_MAX_LRO_DESCRIPTORS;
+	adapter->rx_ring[i].lro_mgr.get_skb_header = ixgbe_get_skb_hdr;
+	adapter->rx_ring[i].lro_mgr.features = LRO_F_EXTRACT_VLAN_ID;
+	if (!(adapter->flags & IXGBE_FLAG_IN_NETPOLL))
+		adapter->rx_ring[i].lro_mgr.features |= LRO_F_NAPI;
+	adapter->rx_ring[i].lro_mgr.dev = adapter->netdev;
+	adapter->rx_ring[i].lro_mgr.ip_summed = CHECKSUM_UNNECESSARY;
+	adapter->rx_ring[i].lro_mgr.ip_summed_aggr = CHECKSUM_UNNECESSARY;
+
 	if (adapter->flags & IXGBE_FLAG_RSS_ENABLED) {
 		/* Fill out redirection table */
 		for (i = 0, j = 0; i < 128; i++, j++) {
@@ -2489,12 +2543,18 @@
 	struct pci_dev *pdev = adapter->pdev;
 	int size;
 
+	size = sizeof(struct net_lro_desc) * IXGBE_MAX_LRO_DESCRIPTORS;
+	rxdr->lro_mgr.lro_arr = vmalloc(size);
+	if (!rxdr->lro_mgr.lro_arr)
+		return -ENOMEM;
+	memset(rxdr->lro_mgr.lro_arr, 0, size);
+
 	size = sizeof(struct ixgbe_rx_buffer) * rxdr->count;
 	rxdr->rx_buffer_info = vmalloc(size);
 	if (!rxdr->rx_buffer_info) {
 		DPRINTK(PROBE, ERR,
 			"vmalloc allocation failed for the rx desc ring\n");
-		return -ENOMEM;
+		goto alloc_failed;
 	}
 	memset(rxdr->rx_buffer_info, 0, size);
 
@@ -2508,13 +2568,18 @@
 		DPRINTK(PROBE, ERR,
 			"Memory allocation failed for the rx desc ring\n");
 		vfree(rxdr->rx_buffer_info);
-		return -ENOMEM;
+		goto alloc_failed;
 	}
 
 	rxdr->next_to_clean = 0;
 	rxdr->next_to_use = 0;
 
 	return 0;
+
+alloc_failed:
+	vfree(rxdr->lro_mgr.lro_arr);
+	rxdr->lro_mgr.lro_arr = NULL;
+	return -ENOMEM;
 }
 
 /**
@@ -2565,6 +2630,9 @@
 {
 	struct pci_dev *pdev = adapter->pdev;
 
+	vfree(rx_ring->lro_mgr.lro_arr);
+	rx_ring->lro_mgr.lro_arr = NULL;
+
 	ixgbe_clean_rx_ring(adapter, rx_ring);
 
 	vfree(rx_ring->rx_buffer_info);
@@ -3517,6 +3585,7 @@
 			   NETIF_F_HW_VLAN_RX |
 			   NETIF_F_HW_VLAN_FILTER;
 
+	netdev->features |= NETIF_F_LRO;
 	netdev->features |= NETIF_F_TSO;
 	netdev->features |= NETIF_F_TSO6;