IPoIB: add LRO support

Add "ipoib_use_lro" module parameter to enable LRO and an
"ipoib_lro_max_aggr" module parameter to set the max number of packets
to be aggregated.  Make LRO controllable and LRO statistics accessible
through ethtool.

Signed-off-by: Vladimir Sokolovsky <vlad@mellanox.co.il>
Signed-off-by: Eli Cohen <eli@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_main.c b/drivers/infiniband/ulp/ipoib/ipoib_main.c
index bfe1dbf99207..fead88f7fb17 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -60,6 +60,15 @@ MODULE_PARM_DESC(send_queue_size, "Number of descriptors in send queue");
 module_param_named(recv_queue_size, ipoib_recvq_size, int, 0444);
 MODULE_PARM_DESC(recv_queue_size, "Number of descriptors in receive queue");
 
+static int lro;
+module_param(lro, bool, 0444);
+MODULE_PARM_DESC(lro,  "Enable LRO (Large Receive Offload)");
+
+static int lro_max_aggr = IPOIB_LRO_MAX_AGGR;
+module_param(lro_max_aggr, int, 0644);
+MODULE_PARM_DESC(lro_max_aggr, "LRO: Max packets to be aggregated "
+		"(default = 64)");
+
 #ifdef CONFIG_INFINIBAND_IPOIB_DEBUG
 int ipoib_debug_level;
 
@@ -936,6 +945,54 @@ static const struct header_ops ipoib_header_ops = {
 	.create	= ipoib_hard_header,
 };
 
+static int get_skb_hdr(struct sk_buff *skb, void **iphdr,
+		       void **tcph, u64 *hdr_flags, void *priv)
+{
+	unsigned int ip_len;
+	struct iphdr *iph;
+
+	if (unlikely(skb->protocol != htons(ETH_P_IP)))
+		return -1;
+
+	/*
+	 * In the future we may add an else clause that verifies the
+	 * checksum and allows devices which do not calculate checksum
+	 * to use LRO.
+	 */
+	if (unlikely(skb->ip_summed != CHECKSUM_UNNECESSARY))
+		return -1;
+
+	/* Check for non-TCP packet */
+	skb_reset_network_header(skb);
+	iph = ip_hdr(skb);
+	if (iph->protocol != IPPROTO_TCP)
+		return -1;
+
+	ip_len = ip_hdrlen(skb);
+	skb_set_transport_header(skb, ip_len);
+	*tcph = tcp_hdr(skb);
+
+	/* check if IP header and TCP header are complete */
+	if (ntohs(iph->tot_len) < ip_len + tcp_hdrlen(skb))
+		return -1;
+
+	*hdr_flags = LRO_IPV4 | LRO_TCP;
+	*iphdr = iph;
+
+	return 0;
+}
+
+static void ipoib_lro_setup(struct ipoib_dev_priv *priv)
+{
+	priv->lro.lro_mgr.max_aggr	 = lro_max_aggr;
+	priv->lro.lro_mgr.max_desc	 = IPOIB_MAX_LRO_DESCRIPTORS;
+	priv->lro.lro_mgr.lro_arr	 = priv->lro.lro_desc;
+	priv->lro.lro_mgr.get_skb_header = get_skb_hdr;
+	priv->lro.lro_mgr.features	 = LRO_F_NAPI;
+	priv->lro.lro_mgr.dev		 = priv->dev;
+	priv->lro.lro_mgr.ip_summed_aggr = CHECKSUM_UNNECESSARY;
+}
+
 static void ipoib_setup(struct net_device *dev)
 {
 	struct ipoib_dev_priv *priv = netdev_priv(dev);
@@ -975,6 +1032,8 @@ static void ipoib_setup(struct net_device *dev)
 
 	priv->dev = dev;
 
+	ipoib_lro_setup(priv);
+
 	spin_lock_init(&priv->lock);
 	spin_lock_init(&priv->tx_lock);
 
@@ -1152,6 +1211,9 @@ static struct net_device *ipoib_add_port(const char *format,
 		priv->dev->features |= NETIF_F_SG | NETIF_F_IP_CSUM;
 	}
 
+	if (lro)
+		priv->dev->features |= NETIF_F_LRO;
+
 	/*
 	 * Set the full membership bit, so that we join the right
 	 * broadcast group, etc.