From: Ben Hutchings <bhutchings@solarflare.com>
To: Eli Cohen <eli@dev.mellanox.co.il>
Cc: netdev@vger.kernel.org, themann@de.ibm.com, linux-kernel@vger.kernel.org
Subject: Re: LRO num of frags limit
Date: Tue, 16 Sep 2008 11:40:17 +0100 [thread overview]
Message-ID: <1221561617.3244.78.camel@achroite> (raw)
In-Reply-To: <20080916073632.GA25226@mtls03>
On Tue, 2008-09-16 at 10:36 +0300, Eli Cohen wrote:
> Hi,
>
> looking at the LRO code, at __lro_proc_segment(), it seems that the
> network driver can configure lro_mgr->max_aggr to any value it wants
> while the number of fragments aggregated must not exceed MAX_SKB_FRAGS
Correct.
> (since we only use a single SKB to aggregate fragments, allocated by
> lro_gen_skb()). Moreover, even if the driver does limit
> lro_mgr->max_aggr to MAX_SKB_FRAGS, it might still cause overflow
> since subsequent aggregations are done at lro_add_frags() which is
> called before checking whether we overflow.
So you must set max_aggr to
MAX_SKB_FRAGS - max number of frags added at once + 1.
> If the above observation is correct, I can send a patch.
I would be interested to see that, anyway.
Ben.
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
next prev parent reply other threads:[~2008-09-16 10:40 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-16 7:36 LRO num of frags limit Eli Cohen
2008-09-16 10:40 ` Ben Hutchings [this message]
2008-09-16 15:25 ` Eli Cohen
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