net: fix packet socket delivery in rx irq handler

This patch fixes the atl1 VLAN warning regression reported by Ramon Casellas.

commit f60d3f0c1a7bf5072a809fdf7bfd39efded725f1

Author: Patrick McHardy <[email protected]>
Date:   Tue Nov 4 13:30:54 2008 +0100

net: fix packet socket delivery in rx irq handler

The changes to deliver hardware accelerated VLAN packets to packet sockets (commit bc1d0411) caused a warning for non-NAPI drivers. The __vlan_hwaccel_rx() function is called directly from the drivers RX function, for non-NAPI drivers that means its still in RX IRQ context:

[ 27.779463] ------------[ cut here ]------------
[ 27.779509] WARNING: at kernel/softirq.c:136 local_bh_enable+0x37/0x81()
...
[ 27.782520] [<c0264755>] netif_nit_deliver+0x5b/0x75
[ 27.782590] [<c02bba83>] __vlan_hwaccel_rx+0x79/0x162
[ 27.782664] [<f8851c1d>] atl1_intr+0x9a9/0xa7c [atl1]
[ 27.782738] [<c0155b17>] handle_IRQ_event+0x23/0x51
[ 27.782808] [<c015692e>] handle_edge_irq+0xc2/0x102
[ 27.782878] [<c0105fd5>] do_IRQ+0x4d/0x64

Split hardware accelerated VLAN reception into two parts to fix this:

- __vlan_hwaccel_rx just stores the VLAN TCI and performs the VLAN device lookup, then calls netif_receive_skb()/netif_rx()

- vlan_hwaccel_do_receive(), which is invoked by netif_receive_skb() in softirq context, performs the real reception and delivery to packet sockets.

index 9e7b49b..a5cb0c3 100644
@@ -114,6 +114,8 @@ extern u16 vlan_dev_vlan_id(const struct net_device *dev);
 
 extern int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp,
 			     u16 vlan_tci, int polling);
+extern int vlan_hwaccel_do_receive(struct sk_buff *skb);
+
 #else
 static inline struct net_device *vlan_dev_real_dev(const struct net_device *dev)
 {

@@ -133,6 +135,11 @@ static inline int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp,
 	BUG();
 	return NET_XMIT_SUCCESS;
 }
+
+static inline int vlan_hwaccel_do_receive(struct sk_buff *skb)
+{
+	return 0;
+}
 #endif
 
 /**

index d9038e3..9174c77 100644
@@ -2218,6 +2218,9 @@ int netif_receive_skb(struct sk_buff *skb)
 	int ret = NET_RX_DROP;
 	__be16 type;
 
+	if (skb->vlan_tci && vlan_hwaccel_do_receive(skb))
+		return NET_RX_SUCCESS;
+
 	/* if we've gotten here through NAPI, check netpoll */
 	if (netpoll_receive_skb(skb))
 		return NET_RX_DROP;

From: Patrick McHardy <[email protected]>
Date: Tue, 04 Nov 2008 13:52:41 +0100

Applied, thanks Patrick.