From patchwork Sat Jun 5 10:14:48 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Xin, Xiaohui" X-Patchwork-Id: 104414 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 o55ABxFp004184 for ; Sat, 5 Jun 2010 10:12:00 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932903Ab0FEKLN (ORCPT ); Sat, 5 Jun 2010 06:11:13 -0400 Received: from mga01.intel.com ([192.55.52.88]:65455 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932872Ab0FEKHG (ORCPT ); Sat, 5 Jun 2010 06:07:06 -0400 Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga101.fm.intel.com with ESMTP; 05 Jun 2010 03:03:03 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,366,1272870000"; d="scan'208";a="804988053" Received: from unknown (HELO localhost.localdomain) ([10.239.36.142]) by fmsmga001.fm.intel.com with ESMTP; 05 Jun 2010 03:06:45 -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, herbert@gondor.hengli.com.au, jdike@linux.intel.com Cc: Xin Xiaohui Subject: [RFC PATCH v7 09/19] Ignore room skb_reserve() when device is using external buffer. Date: Sat, 5 Jun 2010 18:14:48 +0800 Message-Id: <1275732899-5423-9-git-send-email-xiaohui.xin@intel.com> X-Mailer: git-send-email 1.5.4.4 In-Reply-To: <1275732899-5423-8-git-send-email-xiaohui.xin@intel.com> References: <1275732899-5423-1-git-send-email-xiaohui.xin@intel.com> <1275732899-5423-2-git-send-email-xiaohui.xin@intel.com> <1275732899-5423-3-git-send-email-xiaohui.xin@intel.com> <1275732899-5423-4-git-send-email-xiaohui.xin@intel.com> <1275732899-5423-5-git-send-email-xiaohui.xin@intel.com> <1275732899-5423-6-git-send-email-xiaohui.xin@intel.com> <1275732899-5423-7-git-send-email-xiaohui.xin@intel.com> <1275732899-5423-8-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]); Sat, 05 Jun 2010 10:12:00 +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; }