From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Westphal Subject: Re: [PATCH net-next 08/10] hv_netvsc: Don't ask for additional head room in the skb Date: Tue, 24 Nov 2015 09:55:32 +0100 Message-ID: <20151124085532.GA1740@breakpoint.cc> References: <1448321324-21318-1-git-send-email-kys@microsoft.com> <1448321346-21357-1-git-send-email-kys@microsoft.com> <1448321346-21357-8-git-send-email-kys@microsoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, jasowang@redhat.com To: "K. Y. Srinivasan" Return-path: Content-Disposition: inline In-Reply-To: <1448321346-21357-8-git-send-email-kys@microsoft.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org K. Y. Srinivasan wrote: > The rndis header is 116 bytes big and can be placed in the default > head room that will be available in the skb. Since the netvsc packet > is less than 48 bytes, we can use the skb control buffer > for the netvsc packet. With these changes we don't need to > ask for additional head room. Minor nit: could you add a BUILD_BUG_ON test for this? Something like BUILD_BUG_ON(sizeof(struct hv_netvsc_packet) > FIELD_SIZEOF(struct sk_buff, cb));