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Date: Fri, 12 Feb 2010 15:39:07 -0800 (PST)
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To: caoco2002@yahoo.com
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Subject: Re: bug and question in tcp stack
From: David Miller <davem@davemloft.net>
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From: Joe Cao <caoco2002@yahoo.com>
Date: Fri, 12 Feb 2010 15:22:16 -0800 (PST)

> if (tcp_retransmit_skb(sk, tcp_write_queue_head(sk)) > 0) {
> 
> checks the return value as a positive number, which will never be true.

It can, recheck the code paths.

The upcall to send an SKB out through the packet schedular and onwards
to the actual device can return congestion notification values, which
are positive.