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From: Eric Dumazet <eric.dumazet@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net-next] tcp: reduce skb overhead in selected places
Date: Wed, 25 Jan 2017 13:40:12 -0800	[thread overview]
Message-ID: <1485380412.5145.59.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <20170125.140302.1425628250874176845.davem@davemloft.net>

On Wed, 2017-01-25 at 14:03 -0500, David Miller wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Wed, 25 Jan 2017 10:38:52 -0800
> 
> > Do you think we could change __pskb_pull_tail() right away and fix the
> > few places that would break, or should we add various helpers with extra
> > parameters to take a safe route ?
> 
> It should always be safe as long as we see no socket attached on RX,
> right?
> 
> That's the only real case where truesize adjustments can cause trouble.
Queue can be virtual, as for xmit path, tracking skb->truesize in
sk->sk_wmem_alloc.

If a layer calls pskb_may_pull(), we can not change skb->truesize
without also changing skb->sk->sk_wmem_alloc, or sock_wfree() will
trigger bugs.

      reply	other threads:[~2017-01-25 21:40 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-24 22:57 [PATCH net-next] tcp: reduce skb overhead in selected places Eric Dumazet
2017-01-25 18:17 ` David Miller
2017-01-25 18:38   ` Eric Dumazet
2017-01-25 19:03     ` David Miller
2017-01-25 21:40       ` Eric Dumazet [this message]

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