From: Eric Dumazet <eric.dumazet@gmail.com>
To: Vijay Subramanian <subramanian.vijay@gmail.com>
Cc: Tom Herbert <therbert@google.com>,
Linux Netdev List <netdev@vger.kernel.org>,
David Miller <davem@davemloft.net>
Subject: Re: Bug in computing data_len in tcp_sendmsg?
Date: Thu, 01 Dec 2011 23:30:21 +0100 [thread overview]
Message-ID: <1322778621.2750.48.camel@edumazet-laptop> (raw)
In-Reply-To: <CAGK4HS8fLWwdPsrag6+Mz93_ZNg2B5JRjx2s=Re8_Qiv4V=T=w@mail.gmail.com>
Le jeudi 01 décembre 2011 à 14:18 -0800, Vijay Subramanian a écrit :
> >
> > Or the "bug" was to assume that skb was headless.
> > It was true until recently.
> >
> > We recently added commit f07d960df33c5aef
> > (tcp: avoid frag allocation for small frames)
> >
> > to avoid page allocation for small frames.
> >
> > So now, skb can contain in head part of tcp data.
> >
> >
>
> Hi,
> I am looking at tcp_mtu_probe() and was wondering if this commit also
> impacts this function. Once the data are copied from skbs in the write
> queue to the probe skb, copied data are cleared from the original skbs
> in the write queue.
>
> It looks like the code assumes that the original skb will have data
> either in linear part or in paged part. The call to
> __pskb_trim_head(skb, copy) for example does not clear linear part.
>
> Can someone more familiar with the code take a look? Apologies if I
> have read this wrong.
>
tcp_mtu_probe() builds a linear skb, and populate it using
skb_copy_bits() [ this is frag aware, and aware of payload in header as
well ]
I see no problem in it.
next prev parent reply other threads:[~2011-12-01 22:30 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-01 1:48 Bug in computing data_len in tcp_sendmsg? Tom Herbert
2011-12-01 3:42 ` Eric Dumazet
2011-12-01 4:06 ` Tom Herbert
2011-12-01 4:16 ` David Miller
2011-12-01 4:17 ` Eric Dumazet
2011-12-01 5:09 ` Tom Herbert
2011-12-01 9:15 ` Eric Dumazet
2011-12-01 17:29 ` Jesse Brandeburg
2011-12-01 18:04 ` David Miller
2011-12-01 20:37 ` Eric Dumazet
2011-12-01 22:18 ` Vijay Subramanian
2011-12-01 22:30 ` Eric Dumazet [this message]
2011-12-02 6:18 ` Vijay Subramanian
2011-12-02 11:59 ` Eric Dumazet
2011-12-02 15:44 ` Eric Dumazet
2011-12-02 16:05 ` Eric Dumazet
2011-12-02 18:13 ` David Miller
2011-12-02 18:36 ` Eric Dumazet
2011-12-02 18:40 ` David Miller
2011-12-02 20:22 ` Eric Dumazet
2011-12-02 20:24 ` David Miller
2011-12-02 20:45 ` Eric Dumazet
2011-12-02 20:48 ` Eric Dumazet
2011-12-02 21:30 ` David Miller
2011-12-03 15:09 ` Eric Dumazet
2011-12-04 7:39 ` [PATCH] tcp: take care of misalignments Eric Dumazet
2011-12-04 18:21 ` David Miller
2011-12-04 18:51 ` Eric Dumazet
2011-12-05 23:45 ` David Miller
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