From patchwork Fri May 21 09:30:25 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Xin, Xiaohui" X-Patchwork-Id: 101368 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.3/8.14.3) with ESMTP id o4L9T2TA010426 for ; Fri, 21 May 2010 09:29:04 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757814Ab0EUJ1O (ORCPT ); Fri, 21 May 2010 05:27:14 -0400 Received: from mga01.intel.com ([192.55.52.88]:44930 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755074Ab0EUJXz (ORCPT ); Fri, 21 May 2010 05:23:55 -0400 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga101.fm.intel.com with ESMTP; 21 May 2010 02:20:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,277,1272870000"; d="scan'208";a="569306366" Received: from unknown (HELO localhost.localdomain) ([10.239.36.106]) by fmsmga002.fm.intel.com with ESMTP; 21 May 2010 02:22:57 -0700 From: xiaohui.xin@intel.com To: netdev@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, mst@redhat.com, mingo@elte.hu, davem@davemloft.net, jdike@linux.intel.com Cc: Xin Xiaohui Subject: [RFC][PATCH v6 09/19] Ignore room skb_reserve() when device is using external buffer. Date: Fri, 21 May 2010 17:30:25 +0800 Message-Id: <1274434235-5929-10-git-send-email-xiaohui.xin@intel.com> X-Mailer: git-send-email 1.5.4.4 In-Reply-To: <1274434235-5929-9-git-send-email-xiaohui.xin@intel.com> References: <1274434235-5929-1-git-send-email-xiaohui.xin@intel.com> <1274434235-5929-2-git-send-email-xiaohui.xin@intel.com> <1274434235-5929-3-git-send-email-xiaohui.xin@intel.com> <1274434235-5929-4-git-send-email-xiaohui.xin@intel.com> <1274434235-5929-5-git-send-email-xiaohui.xin@intel.com> <1274434235-5929-6-git-send-email-xiaohui.xin@intel.com> <1274434235-5929-7-git-send-email-xiaohui.xin@intel.com> <1274434235-5929-8-git-send-email-xiaohui.xin@intel.com> <1274434235-5929-9-git-send-email-xiaohui.xin@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Fri, 21 May 2010 09:29:04 +0000 (UTC) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 5ff8c27..193b259 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1200,6 +1200,15 @@ static inline int skb_tailroom(const struct sk_buff *skb) */ static inline void skb_reserve(struct sk_buff *skb, int len) { + /* Since skb_reserve() is only for an empty buffer, + * and when the skb is getting external buffer, we cannot + * retain the external buffer has the same reserved space + * in the header which kernel allocatd skb has, so have to + * ignore this. And we have recorded the external buffer + * info in the destructor_arg field, so use it as indicator. + */ + if (skb_shinfo(skb)->destructor_arg) + return; skb->data += len; skb->tail += len; }