Re: [PATCH net-next-2.6] net: Introduce skb_orphan_try()

[David Miller <davem@davemloft.net>]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 22 Apr 2010 09:10:33 +0200

> Le mercredi 21 avril 2010 à 22:56 -0700, David Miller a écrit :
> 
>> Right, I've applied this, thanks.
>> 
>> What we should probably do instead is call and NULL out the
>> DEV_GSO_CB() destructor.  Right?
> 
> Yes, probably, I'll take a look at this if you want.

It might look something like this:

diff --git a/net/core/dev.c b/net/core/dev.c
index 9bf1ccc..13241da 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1892,6 +1892,20 @@ static inline void skb_orphan_try(struct sk_buff *skb)
 		skb_orphan(skb);
 }
 
+/*
+ * GSO packets need to be handled specially because such packets
+ * hold the normal SKB destructor in a backup pointer.
+ */
+static inline void skb_orphan_try_gso(struct sk_buff *skb)
+{
+	if (!skb_tx(skb)->flags) {
+		if (DEV_GSO_CB(skb)->destructor)
+			DEV_GSO_CB(skb)->destructor(skb);
+		DEV_GSO_CB(skb)->destructor = NULL;
+		skb->sk = NULL;
+	}
+}
+
 int dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev,
 			struct netdev_queue *txq)
 {
@@ -1937,6 +1951,7 @@ gso:
 		if (dev->priv_flags & IFF_XMIT_DST_RELEASE)
 			skb_dst_drop(nskb);
 
+		skb_orphan_try_gso(skb);
 		rc = ops->ndo_start_xmit(nskb, dev);
 		if (unlikely(rc != NETDEV_TX_OK)) {
 			if (rc & ~NETDEV_TX_MASK)