From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [net-next 05/10] net: Add Geneve tunneling protocol driver
Date: Wed, 23 Jul 2014 11:20:12 -0700
Message-ID: <20140723112012.0bf89a0f@haswell>
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	<1406024393-6778-6-git-send-email-azhou@nicira.com>
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Cc: davem@davemloft.net, netdev@vger.kernel.org,
	Jesse Gross <jesse@nicira.com>
To: Andy Zhou <azhou@nicira.com>
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On Tue, 22 Jul 2014 03:19:48 -0700
Andy Zhou <azhou@nicira.com> wrote:

> +	geneveh->ver = GENEVE_VER;
> +	geneveh->opt_len = options_len / 4;
> +	geneveh->oam = !!(tun_flags & TUNNEL_OAM);
> +	geneveh->critical = !!(tun_flags & TUNNEL_CRIT_OPT);
> +	geneveh->rsvd1 = 0;

Bitfield's suck in C.

Setting bitfield values individually generates slow code because
the compiler has to generate multiple mask operations.

Better to change this part to one set of shifts and do one load.