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Commit 9b22ea56 authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

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.

Reported-and-tested-by: default avatarRamon Casellas <ramon.casellas@cttc.es>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 79654a76

include/linux/if_vlan.h

+7 −0
Original line number Diff line number Diff line
@@ -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



/**

net/8021q/vlan_core.c

+33 −13
Original line number Diff line number Diff line
@@ -3,11 +3,20 @@ 
#include <linux/if_vlan.h>

#include "vlan.h"



struct vlan_hwaccel_cb {

	struct net_device	*dev;

};



static inline struct vlan_hwaccel_cb *vlan_hwaccel_cb(struct sk_buff *skb)

{

	return (struct vlan_hwaccel_cb *)skb->cb;

}



/* VLAN rx hw acceleration helper.  This acts like netif_{rx,receive_skb}(). */

int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp,

		      u16 vlan_tci, int polling)

{

	struct net_device_stats *stats;

	struct vlan_hwaccel_cb *cb = vlan_hwaccel_cb(skb);



	if (skb_bond_should_drop(skb)) {

		dev_kfree_skb_any(skb);
@@ -15,23 +24,35 @@ int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp, 
	}



	skb->vlan_tci = vlan_tci;

	cb->dev = vlan_group_get_device(grp, vlan_tci & VLAN_VID_MASK);



	return (polling ? netif_receive_skb(skb) : netif_rx(skb));

}

EXPORT_SYMBOL(__vlan_hwaccel_rx);



int vlan_hwaccel_do_receive(struct sk_buff *skb)

{

	struct vlan_hwaccel_cb *cb = vlan_hwaccel_cb(skb);

	struct net_device *dev = cb->dev;

	struct net_device_stats *stats;



	netif_nit_deliver(skb);



	skb->dev = vlan_group_get_device(grp, vlan_tci & VLAN_VID_MASK);

	if (skb->dev == NULL) {

		dev_kfree_skb_any(skb);

		/* Not NET_RX_DROP, this is not being dropped

		 * due to congestion. */

		return NET_RX_SUCCESS;

	if (dev == NULL) {

		kfree_skb(skb);

		return -1;

	}

	skb->dev->last_rx = jiffies;



	skb->dev = dev;

	skb->priority = vlan_get_ingress_priority(dev, skb->vlan_tci);

	skb->vlan_tci = 0;



	stats = &skb->dev->stats;

	dev->last_rx = jiffies;



	stats = &dev->stats;

	stats->rx_packets++;

	stats->rx_bytes += skb->len;



	skb->priority = vlan_get_ingress_priority(skb->dev, vlan_tci);

	switch (skb->pkt_type) {

	case PACKET_BROADCAST:

		break;
@@ -43,13 +64,12 @@ int __vlan_hwaccel_rx(struct sk_buff *skb, struct vlan_group *grp, 
		 * This allows the VLAN to have a different MAC than the

		 * underlying device, and still route correctly. */

		if (!compare_ether_addr(eth_hdr(skb)->h_dest,

					skb->dev->dev_addr))

					dev->dev_addr))

			skb->pkt_type = PACKET_HOST;

		break;

	};

	return (polling ? netif_receive_skb(skb) : netif_rx(skb));

	return 0;

}

EXPORT_SYMBOL(__vlan_hwaccel_rx);



struct net_device *vlan_dev_real_dev(const struct net_device *dev)

{

net/core/dev.c

+3 −0
Original line number Diff line number Diff line
@@ -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;