igb: Replace LRO with GRO

This patch makes igb invoke the GRO hooks instead of LRO.  As
GRO has a compatible external interface to LRO this is a very
straightforward replacement.

Three things of note:

1) I've kept the LRO Kconfig option until we decide to enable
GRO across the board at which point it can also be killed.

2) The poll_controller stuff is broken in igb as it tries to do
the same work as the normal poll routine.  Since poll_controller
can be called in the middle of a poll, this can't be good.

I noticed this because poll_controller can invoke the GRO hooks
without flushing held GRO packets.

However, this should be harmless (assuming the poll_controller
bug above doesn't kill you first :) since the next ->poll will
clear the backlog.  The only time when we'll have a problem is
if we're already executing the GRO code on the same ring, but
that's no worse than what happens now.

3) I kept the ip_summed check before calling GRO so that we're
on par with previous behaviour.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/Kconfig

@@ -2022,7 +2022,6 @@ config IGB
 config IGB_LRO 
 	bool "Use software LRO"
 	depends on IGB && INET
-	select INET_LRO
 	---help---
 	  Say Y here if you want to use large receive offload. 
 

drivers/net/igb/igb.h

@@ -36,12 +36,6 @@
 
 struct igb_adapter;
 
-#ifdef CONFIG_IGB_LRO
-#include <linux/inet_lro.h>
-#define MAX_LRO_AGGR                      32
-#define MAX_LRO_DESCRIPTORS                8
-#endif
-
 /* Interrupt defines */
 #define IGB_MIN_DYN_ITR 3000
 #define IGB_MAX_DYN_ITR 96000
@@ -176,10 +170,6 @@ struct igb_ring {
 			struct napi_struct napi;
 			int set_itr;
 			struct igb_ring *buddy;
-#ifdef CONFIG_IGB_LRO
-			struct net_lro_mgr lro_mgr;
-			bool lro_used;
-#endif
 		};
 	};
 
@@ -288,12 +278,6 @@ struct igb_adapter {
 	int need_ioport;
 
 	struct igb_ring *multi_tx_table[IGB_MAX_TX_QUEUES];
-#ifdef CONFIG_IGB_LRO
-	unsigned int lro_max_aggr;
-	unsigned int lro_aggregated;
-	unsigned int lro_flushed;
-	unsigned int lro_no_desc;
-#endif
 	unsigned int tx_ring_count;
 	unsigned int rx_ring_count;
 };

drivers/net/igb/igb_ethtool.c

@@ -93,11 +93,6 @@ static const struct igb_stats igb_gstrings_stats[] = {
 	{ "tx_smbus", IGB_STAT(stats.mgptc) },
 	{ "rx_smbus", IGB_STAT(stats.mgprc) },
 	{ "dropped_smbus", IGB_STAT(stats.mgpdc) },
-#ifdef CONFIG_IGB_LRO
-	{ "lro_aggregated", IGB_STAT(lro_aggregated) },
-	{ "lro_flushed", IGB_STAT(lro_flushed) },
-	{ "lro_no_desc", IGB_STAT(lro_no_desc) },
-#endif
 };
 
 #define IGB_QUEUE_STATS_LEN \
@@ -1921,18 +1916,6 @@ static void igb_get_ethtool_stats(struct net_device *netdev,
 	int stat_count = sizeof(struct igb_queue_stats) / sizeof(u64);
 	int j;
 	int i;
-#ifdef CONFIG_IGB_LRO
-	int aggregated = 0, flushed = 0, no_desc = 0;
-
-	for (i = 0; i < adapter->num_rx_queues; i++) {
-		aggregated += adapter->rx_ring[i].lro_mgr.stats.aggregated;
-		flushed += adapter->rx_ring[i].lro_mgr.stats.flushed;
-		no_desc += adapter->rx_ring[i].lro_mgr.stats.no_desc;
-	}
-	adapter->lro_aggregated = aggregated;
-	adapter->lro_flushed = flushed;
-	adapter->lro_no_desc = no_desc;
-#endif
 
 	igb_update_stats(adapter);
 	for (i = 0; i < IGB_GLOBAL_STATS_LEN; i++) {

drivers/net/igb/igb_main.c

@@ -115,9 +115,6 @@ static bool igb_clean_tx_irq(struct igb_ring *);
 static int igb_poll(struct napi_struct *, int);
 static bool igb_clean_rx_irq_adv(struct igb_ring *, int *, int);
 static void igb_alloc_rx_buffers_adv(struct igb_ring *, int);
-#ifdef CONFIG_IGB_LRO
-static int igb_get_skb_hdr(struct sk_buff *skb, void **, void **, u64 *, void *);
-#endif
 static int igb_ioctl(struct net_device *, struct ifreq *, int cmd);
 static void igb_tx_timeout(struct net_device *);
 static void igb_reset_task(struct work_struct *);
@@ -1189,7 +1186,7 @@ static int __devinit igb_probe(struct pci_dev *pdev,
 	netdev->features |= NETIF_F_TSO6;
 
 #ifdef CONFIG_IGB_LRO
-	netdev->features |= NETIF_F_LRO;
+	netdev->features |= NETIF_F_GRO;
 #endif
 
 	netdev->vlan_features |= NETIF_F_TSO;
@@ -1739,14 +1736,6 @@ int igb_setup_rx_resources(struct igb_adapter *adapter,
 	struct pci_dev *pdev = adapter->pdev;
 	int size, desc_len;
 
-#ifdef CONFIG_IGB_LRO
-	size = sizeof(struct net_lro_desc) * MAX_LRO_DESCRIPTORS;
-	rx_ring->lro_mgr.lro_arr = vmalloc(size);
-	if (!rx_ring->lro_mgr.lro_arr)
-		goto err;
-	memset(rx_ring->lro_mgr.lro_arr, 0, size);
-#endif
-
 	size = sizeof(struct igb_buffer) * rx_ring->count;
 	rx_ring->buffer_info = vmalloc(size);
 	if (!rx_ring->buffer_info)
@@ -1773,10 +1762,6 @@ int igb_setup_rx_resources(struct igb_adapter *adapter,
 	return 0;
 
 err:
-#ifdef CONFIG_IGB_LRO
-	vfree(rx_ring->lro_mgr.lro_arr);
-	rx_ring->lro_mgr.lro_arr = NULL;
-#endif
 	vfree(rx_ring->buffer_info);
 	dev_err(&adapter->pdev->dev, "Unable to allocate memory for "
 		"the receive descriptor ring\n");
@@ -1930,16 +1915,6 @@ static void igb_configure_rx(struct igb_adapter *adapter)
 		rxdctl |= IGB_RX_HTHRESH << 8;
 		rxdctl |= IGB_RX_WTHRESH << 16;
 		wr32(E1000_RXDCTL(j), rxdctl);
-#ifdef CONFIG_IGB_LRO
-		/* Intitial LRO Settings */
-		ring->lro_mgr.max_aggr = MAX_LRO_AGGR;
-		ring->lro_mgr.max_desc = MAX_LRO_DESCRIPTORS;
-		ring->lro_mgr.get_skb_header = igb_get_skb_hdr;
-		ring->lro_mgr.features = LRO_F_NAPI | LRO_F_EXTRACT_VLAN_ID;
-		ring->lro_mgr.dev = adapter->netdev;
-		ring->lro_mgr.ip_summed = CHECKSUM_UNNECESSARY;
-		ring->lro_mgr.ip_summed_aggr = CHECKSUM_UNNECESSARY;
-#endif
 	}
 
 	if (adapter->num_rx_queues > 1) {
@@ -2128,11 +2103,6 @@ void igb_free_rx_resources(struct igb_ring *rx_ring)
 	vfree(rx_ring->buffer_info);
 	rx_ring->buffer_info = NULL;
 
-#ifdef CONFIG_IGB_LRO
-	vfree(rx_ring->lro_mgr.lro_arr);
-	rx_ring->lro_mgr.lro_arr = NULL;
-#endif 
-
 	pci_free_consistent(pdev, rx_ring->size, rx_ring->desc, rx_ring->dma);
 
 	rx_ring->desc = NULL;
@@ -3768,39 +3738,6 @@ static bool igb_clean_tx_irq(struct igb_ring *tx_ring)
 	return (count < tx_ring->count);
 }
 
-#ifdef CONFIG_IGB_LRO
- /**
- * igb_get_skb_hdr - helper function for LRO header processing
- * @skb: pointer to sk_buff to be added to LRO packet
- * @iphdr: pointer to ip header structure
- * @tcph: pointer to tcp header structure
- * @hdr_flags: pointer to header flags
- * @priv: pointer to the receive descriptor for the current sk_buff
- **/
-static int igb_get_skb_hdr(struct sk_buff *skb, void **iphdr, void **tcph,
-                           u64 *hdr_flags, void *priv)
-{
-	union e1000_adv_rx_desc *rx_desc = priv;
-	u16 pkt_type = rx_desc->wb.lower.lo_dword.pkt_info &
-	               (E1000_RXDADV_PKTTYPE_IPV4 | E1000_RXDADV_PKTTYPE_TCP);
-
-	/* Verify that this is a valid IPv4 TCP packet */
-	if (pkt_type != (E1000_RXDADV_PKTTYPE_IPV4 |
-	                  E1000_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;
-
-}
-#endif /* CONFIG_IGB_LRO */
-
 /**
  * igb_receive_skb - helper function to handle rx indications
  * @ring: pointer to receive ring receving this packet 
@@ -3815,28 +3752,20 @@ static void igb_receive_skb(struct igb_ring *ring, u8 status,
 	struct igb_adapter * adapter = ring->adapter;
 	bool vlan_extracted = (adapter->vlgrp && (status & E1000_RXD_STAT_VP));
 
-#ifdef CONFIG_IGB_LRO
-	if (adapter->netdev->features & NETIF_F_LRO &&
-	    skb->ip_summed == CHECKSUM_UNNECESSARY) {
+	if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
 		if (vlan_extracted)
-			lro_vlan_hwaccel_receive_skb(&ring->lro_mgr, skb,
-			                   adapter->vlgrp,
-			                   le16_to_cpu(rx_desc->wb.upper.vlan),
-			                   rx_desc);
+			vlan_gro_receive(&ring->napi, adapter->vlgrp,
+			                 le16_to_cpu(rx_desc->wb.upper.vlan),
+			                 skb);
 		else
-			lro_receive_skb(&ring->lro_mgr,skb, rx_desc);
-		ring->lro_used = 1;
+			napi_gro_receive(&ring->napi, skb);
 	} else {
-#endif
 		if (vlan_extracted)
 			vlan_hwaccel_receive_skb(skb, adapter->vlgrp,
 			                  le16_to_cpu(rx_desc->wb.upper.vlan));
 		else
-
 			netif_receive_skb(skb);
-#ifdef CONFIG_IGB_LRO
 	}
-#endif
 }
 
 
@@ -3991,13 +3920,6 @@ next_desc:
 	rx_ring->next_to_clean = i;
 	cleaned_count = IGB_DESC_UNUSED(rx_ring);
 
-#ifdef CONFIG_IGB_LRO
-	if (rx_ring->lro_used) {
-		lro_flush_all(&rx_ring->lro_mgr);
-		rx_ring->lro_used = 0;
-	}
-#endif
-
 	if (cleaned_count)
 		igb_alloc_rx_buffers_adv(rx_ring, cleaned_count);