From mboxrd@z Thu Jan 1 00:00:00 1970 From: xiaohui.xin@intel.com Subject: [RFC][PATCH v4 08/18] Ignore skb_reserve() when device is using external buffer. Date: Sun, 25 Apr 2010 17:19:55 +0800 Message-ID: <1272187206-18534-8-git-send-email-xiaohui.xin@intel.com> References: <1272187206-18534-1-git-send-email-xiaohui.xin@intel.com> <1272187206-18534-2-git-send-email-xiaohui.xin@intel.com> <1272187206-18534-3-git-send-email-xiaohui.xin@intel.com> <1272187206-18534-4-git-send-email-xiaohui.xin@intel.com> <1272187206-18534-5-git-send-email-xiaohui.xin@intel.com> <1272187206-18534-6-git-send-email-xiaohui.xin@intel.com> <1272187206-18534-7-git-send-email-xiaohui.xin@intel.com> Cc: Xin Xiaohui 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 Return-path: In-Reply-To: <1272187206-18534-7-git-send-email-xiaohui.xin@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Xin Xiaohui Make the skb->data and skb->head from external buffer to be consistent, we ignore the room reserved by driver for kernel skb. Signed-off-by: Xin Xiaohui Signed-off-by: Zhao Yu Reviewed-by: Jeff Dike --- include/linux/skbuff.h | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 8949b15..4458dc8 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1206,6 +1206,15 @@ 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; } -- 1.5.4.4