Re: pskb_copy() in tcp_transmit_skb()

Le 13 septembre 2011 14:41, Christoph Paasch
[off-list ref] a écrit :

Eric,

On Tuesday 13 September 2011 wrote Eric Dumazet:

quoted

I suggest you read dev_queue_xmit_nit() : Every xmit packet can be
cloned right here.

By the time tcp_retransmit_skb() is called, cloned skb might still be
in a AF_PACKET queue (or even a device TX queue)

Thanks for the clear answer.

So, basically every call to tcp_retransmit_skb on an skb that is also still
hold in an AF_PACKET queue will end up in pskb_copy, because:
1. it has been cloned previously in tcp_transmit_skb()
2. The data_ref > 1 because it's clone is still in an AF_PACKET queue.

Please correct me, if I'm wrong.

Thats correct.