netdev - Re: [PATCH net-next] udp: avoid csum

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Message-Id: <20160601.174151.1773614070251060832.davem@davemloft.net>
Date:	Wed, 01 Jun 2016 17:41:51 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	eric.dumazet@...il.com
Cc:	samanthakumar@...gle.com, willemb@...gle.com,
	netdev@...r.kernel.org
Subject: Re: [PATCH net-next] udp: avoid csum_partial() for validated skb

From: Eric Dumazet <eric.dumazet@...il.com>
Date: Tue, 31 May 2016 15:22:41 -0700

> From: Eric Dumazet <edumazet@...gle.com>
> 
> In commit e6afc8ace6dd5 ("udp: remove headers from UDP packets before
> queueing"), udp_csum_pull_header() helper was added but missed fact
> that CHECKSUM_UNNECESSARY packets were now converted to CHECKSUM_NONE
> and skb->csum_valid was set to 1 for them.
> 
> Since csum_partial() is quite expensive, even for 8-byte area, it is
> worth adding a test.
> 
> We also can use skb->data instead of udp_hdr() as we are pulling
> UDP headers, as it is sightly faster.
> 
> Signed-off-by: Eric Dumazet <edumazet@...gle.com>

Applied, thanks Eric.