From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] IPoIB: fix skb truesize underestimatiom
Date: Tue, 10 Jul 2012 23:37:43 -0700 (PDT)
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Cc: ogerlitz@mellanox.com, erezsh@mellanox.com, roland@purestorage.com,
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From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 10 Jul 2012 22:03:41 +0200

> From: Eric Dumazet <edumazet@google.com>
> 
> Or Gerlitz reported triggering of WARN_ON_ONCE(delta < len); in
> skb_try_coalesce()
> This warning tracks drivers that incorrectly set skb->truesize
> 
> IPoIB indeed allocates a full page to store a fragment, but only
> accounts in skb->truesize the used part of the page (frame length)
> 
> This patch fixes skb truesize underestimation, and
> also fixes a performance issue, because RX skbs have not enough tailroom
> to allow IP and TCP stacks to pull their header in skb linear part
> without an expensive call to pskb_expand_head()
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Or Gerlitz <ogerlitz@mellanox.com>

Applied to net, thanks.