Re: [PATCH] net: increase skb->users instead of skb_clone()

Junchang Wang
2010-12-16T14:21:00Z

On Thu, Dec 16, 2010 at 3:23 PM, Changli Gao <xiaosuo@gmail.com> wrote:

>> You beat me, but I was thinking of a different way, adding a new
>> pt_prev->xmit_func(), handling all the details (no need for atomic ops
>> on skb users if packet is not delivered at all).
>>
>> By the way, your patch is not 100% safe/OK, because af_packet rcv()
>> handler writes on skb (skb_pull() and all)
>>
>
> But af_packet_rcv() restores skbs at last.
>
>        if (skb_head != skb->data && skb_shared(skb)) {
>                skb->data = skb_head;
>                skb->len = skb_len;
>        }
>
If af packet_rcv invokes skb_clone, this skb is differ from the original one.
Eric's warning is right.

--
--Junchang