From patchwork Fri May 7 09:34:56 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Xin, Xiaohui" X-Patchwork-Id: 97691 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 o479ZERu014825 for ; Fri, 7 May 2010 09:35:52 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755435Ab0EGJaI (ORCPT ); Fri, 7 May 2010 05:30:08 -0400 Received: from mga09.intel.com ([134.134.136.24]:55769 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755511Ab0EGJaF (ORCPT ); Fri, 7 May 2010 05:30:05 -0400 Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP; 07 May 2010 02:28:37 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.52,347,1270450800"; d="scan'208";a="515915054" Received: from unknown (HELO localhost.localdomain) ([10.239.36.200]) by orsmga002.jf.intel.com with ESMTP; 07 May 2010 02:29:33 -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 v5 09/19] Ignore room skb_reserve() when device is using external buffer. Date: Fri, 7 May 2010 17:34:56 +0800 Message-Id: <1273224906-4874-10-git-send-email-xiaohui.xin@intel.com> X-Mailer: git-send-email 1.5.4.4 In-Reply-To: <1273224906-4874-9-git-send-email-xiaohui.xin@intel.com> References: <1273224906-4874-1-git-send-email-xiaohui.xin@intel.com> <1273224906-4874-2-git-send-email-xiaohui.xin@intel.com> <1273224906-4874-3-git-send-email-xiaohui.xin@intel.com> <1273224906-4874-4-git-send-email-xiaohui.xin@intel.com> <1273224906-4874-5-git-send-email-xiaohui.xin@intel.com> <1273224906-4874-6-git-send-email-xiaohui.xin@intel.com> <1273224906-4874-7-git-send-email-xiaohui.xin@intel.com> <1273224906-4874-8-git-send-email-xiaohui.xin@intel.com> <1273224906-4874-9-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, 07 May 2010 09:36:34 +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; }