Return-path: Received: from mga11.intel.com ([192.55.52.93]:1092 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753075AbZK0JaM (ORCPT ); Fri, 27 Nov 2009 04:30:12 -0500 Subject: Re: [RFC 1/2] wireless: add ieee80211_asmdu_to_8023s From: Zhu Yi To: Johannes Berg Cc: "linville@tuxdriver.com" , "linux-wireless@vger.kernel.org" In-Reply-To: <1259313653.5428.5.camel@johannes.local> References: <1259215413-16753-1-git-send-email-yi.zhu@intel.com> <1259229943.32372.50.camel@johannes.local> <1259290376.13126.219.camel@debian> <1259313653.5428.5.camel@johannes.local> Content-Type: text/plain; charset="UTF-8" Date: Fri, 27 Nov 2009 17:30:17 +0800 Message-ID: <1259314217.12157.3.camel@debian> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Fri, 2009-11-27 at 17:20 +0800, Johannes Berg wrote: > Is it? I don't think so. Many drivers go up beyond that as far as I > know. Then some do different things like putting it in a different DMA > block. > > > While for those drivers really need a bigger > > extra headroom and support Rx aggregation, this probably means > > ieee80211_skb_resize. But the resize should always happen for every > > packet from the IP stack, right? > > No, davem and I optimised that away a long time ago via using > netdev->needed_headroom and netdev->needed_tailroom. It even works for > bridges and their slave devices, iirc. I missed this. Will check it. If so, I'll add another parameter to pass the extra hw tx headroom to ieee80211_asmdu_to_8023s. Thanks, -yi