[PATCH 1/2] net: allow multiple dev per napi with GRO

[PATCH 1/2] net: allow multiple dev per napi with GRO

[Stephen Hemminger]

GRO assumes that there is a one-to-one relationship between NAPI
structure and network device. Some devices like sky2 share multiple
devices on a single interrupt so only have one NAPI handler. Rather than
split GRO from NAPI, just have GRO assume if device changes that
it is a different flow.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

--- a/net/core/dev.c	2009-04-01 12:02:12.381316147 -0700
+++ b/net/core/dev.c	2009-04-01 12:07:29.718192280 -0700
@@ -2472,8 +2472,9 @@ static int __napi_gro_receive(struct nap
 		return GRO_NORMAL;
 
 	for (p = napi->gro_list; p; p = p->next) {
-		NAPI_GRO_CB(p)->same_flow = !compare_ether_header(
-			skb_mac_header(p), skb_gro_mac_header(skb));
+		NAPI_GRO_CB(p)->same_flow = (p->dev == skb->dev)
+			&& !compare_ether_header(skb_mac_header(p),
+						 skb_gro_mac_header(skb));
 		NAPI_GRO_CB(p)->flush = 0;
 	}
 

[PATCH 2/2] sky2: add GRO support

[Stephen Hemminger]

Add support for generic receive offload. Also cleanup counters so
that only updated once per interrupt.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
----
Note: this is experimental at this point (so please hold for 2.6.31)


--- a/drivers/net/sky2.c	2009-04-01 11:51:55.822315655 -0700
+++ b/drivers/net/sky2.c	2009-04-01 13:13:40.275066435 -0700
@@ -2344,11 +2344,46 @@ static inline void sky2_tx_done(struct n
 	}
 }
 
+static inline void sky2_skb_rx(const struct sky2_port *sky2,
+			       u32 status, struct sk_buff *skb)
+{
+#ifdef SKY2_VLAN_TAG_USED
+	u16 vlan_tag = be16_to_cpu(sky2->rx_tag);
+	if (sky2->vlgrp && (status & GMR_FS_VLAN)) {
+		if (skb->ip_summed == CHECKSUM_NONE)
+			vlan_hwaccel_receive_skb(skb, sky2->vlgrp, vlan_tag);
+		else
+			vlan_gro_receive(&sky2->hw->napi, sky2->vlgrp,
+					 vlan_tag, skb);
+		return;
+	}
+#endif
+	if (skb->ip_summed == CHECKSUM_NONE)
+		netif_receive_skb(skb);
+	else
+		napi_gro_receive(&sky2->hw->napi, skb);
+}
+
+static void sky2_rx_done(struct sky2_hw *hw, unsigned port,
+			       unsigned packets, unsigned bytes)
+{
+	struct net_device *dev = hw->dev[port];
+
+	if (dev) {
+		dev->stats.rx_packets += packets;
+		dev->stats.rx_bytes += bytes;
+		dev->last_rx = jiffies;
+		sky2_rx_update(netdev_priv(dev), rxqaddr[port]);
+	}
+}
+
+
 /* Process status response ring */
 static int sky2_status_intr(struct sky2_hw *hw, int to_do, u16 idx)
 {
 	int work_done = 0;
-	unsigned rx[2] = { 0, 0 };
+	unsigned int total_bytes[2] = { 0 };
+	unsigned int total_packets[2] = { 0 };
 
 	rmb();
 	do {
@@ -2375,7 +2410,8 @@ static int sky2_status_intr(struct sky2_
 		le->opcode = 0;
 		switch (opcode & ~HW_OWNER) {
 		case OP_RXSTAT:
-			++rx[port];
+			total_packets[port]++;
+			total_bytes[port] += length;
 			skb = sky2_receive(dev, length, status);
 			if (unlikely(!skb)) {
 				dev->stats.rx_dropped++;
@@ -2393,18 +2429,8 @@ static int sky2_status_intr(struct sky2_
 			}
 
 			skb->protocol = eth_type_trans(skb, dev);
-			dev->stats.rx_packets++;
-			dev->stats.rx_bytes += skb->len;
-			dev->last_rx = jiffies;
 
-#ifdef SKY2_VLAN_TAG_USED
-			if (sky2->vlgrp && (status & GMR_FS_VLAN)) {
-				vlan_hwaccel_receive_skb(skb,
-							 sky2->vlgrp,
-							 be16_to_cpu(sky2->rx_tag));
-			} else
-#endif
-				netif_receive_skb(skb);
+			sky2_skb_rx(sky2, status, skb);
 
 			/* Stop after net poll weight */
 			if (++work_done >= to_do)
@@ -2474,11 +2500,9 @@ static int sky2_status_intr(struct sky2_
 	sky2_write32(hw, STAT_CTRL, SC_STAT_CLR_IRQ);
 
 exit_loop:
-	if (rx[0])
-		sky2_rx_update(netdev_priv(hw->dev[0]), Q_R1);
 
-	if (rx[1])
-		sky2_rx_update(netdev_priv(hw->dev[1]), Q_R2);
+	sky2_rx_done(hw, 0, total_packets[0], total_bytes[0]);
+	sky2_rx_done(hw, 1, total_packets[1], total_bytes[1]);
 
 	return work_done;
 }
@@ -4245,6 +4269,7 @@ static __devinit struct net_device *sky2
 	sky2->port = port;
 
 	dev->features |= NETIF_F_TSO | NETIF_F_IP_CSUM | NETIF_F_SG;
+	dev->features |= NETIF_F_GRO;
 	if (highmem)
 		dev->features |= NETIF_F_HIGHDMA;
 

Re: [PATCH 2/2] sky2: add GRO support

[David Miller]

From: Stephen Hemminger <shemminger@vyatta.com>
Date: Wed, 1 Apr 2009 14:39:46 -0700

> Add support for generic receive offload. Also cleanup counters so
> that only updated once per interrupt.
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> ----
> Note: this is experimental at this point (so please hold for 2.6.31)

Ok, please just resubmit this when -rc1 is released.

Re: [PATCH 1/2] net: allow multiple dev per napi with GRO

[David Miller]

From: Stephen Hemminger <shemminger@vyatta.com>
Date: Wed, 1 Apr 2009 14:20:20 -0700

> GRO assumes that there is a one-to-one relationship between NAPI
> structure and network device. Some devices like sky2 share multiple
> devices on a single interrupt so only have one NAPI handler. Rather than
> split GRO from NAPI, just have GRO assume if device changes that
> it is a different flow.
> 
> Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>

Looks good, applied.

Re: [PATCH 1/2] net: allow multiple dev per napi with GRO

[Herbert Xu]

On Thu, Apr 02, 2009 at 01:08:01AM -0700, David Miller wrote:
> From: Stephen Hemminger <shemminger@vyatta.com>
> Date: Wed, 1 Apr 2009 14:20:20 -0700
> 
> > GRO assumes that there is a one-to-one relationship between NAPI
> > structure and network device. Some devices like sky2 share multiple
> > devices on a single interrupt so only have one NAPI handler. Rather than
> > split GRO from NAPI, just have GRO assume if device changes that
> > it is a different flow.
> > 
> > Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
> 
> Looks good, applied.

Yep, looks good to me too.  It's only the non-skb interface that
can't handle a shared napi as it uses napi->dev to construct the
skb.

I'm currently experimenting with a new interface to replace the
existing non-skb interface.  The idea is to get the driver to do
what we currently do in napi_fraginfo_skb through helpers.  This
should remove the usage of napi->dev.  It should also remove the
unnecessary double-copying of the frags array.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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