From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH v4 21/42] virtio_net: get rid of virtio_net_hdr/skb_vnet_hdr Date: Wed, 26 Nov 2014 15:11:56 +0200 Message-ID: <20141126131156.GA5127@redhat.com> References: <1416933600-21398-1-git-send-email-mst@redhat.com> <1416933600-21398-22-git-send-email-mst@redhat.com> <20141126135053.1bf4f97c.cornelia.huck@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: rusty@au1.ibm.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, pbonzini@redhat.com, David Miller To: Cornelia Huck Return-path: Content-Disposition: inline In-Reply-To: <20141126135053.1bf4f97c.cornelia.huck@de.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org List-Id: netdev.vger.kernel.org On Wed, Nov 26, 2014 at 01:50:53PM +0100, Cornelia Huck wrote: > On Tue, 25 Nov 2014 18:42:53 +0200 > "Michael S. Tsirkin" wrote: > > > virtio 1.0 doesn't use virtio_net_hdr anymore, and in fact, it's not > > really useful since virtio_net_hdr_mrg_rxbuf includes that as the first > > field anyway. > > > > Let's drop it, precalculate header len and store within vi instead. > > > > This way we can also remove struct skb_vnet_hdr. > > > > Signed-off-by: Michael S. Tsirkin > > --- > > drivers/net/virtio_net.c | 90 ++++++++++++++++++++++-------------------------- > > 1 file changed, 41 insertions(+), 49 deletions(-) > > > > > @@ -260,13 +256,11 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, > > > > hdr = skb_vnet_hdr(skb); > > > > - if (vi->mergeable_rx_bufs) { > > - hdr_len = sizeof hdr->mhdr; > > - hdr_padded_len = sizeof hdr->mhdr; > > - } else { > > - hdr_len = sizeof hdr->hdr; > > + hdr_len = vi->hdr_len; > > + if (vi->mergeable_rx_bufs) > > + hdr_padded_len = sizeof *hdr; > > sizeof without () looks weird to me. It's how it was originally, so I think I'd rather keep it. I kind of like it too: it stresses the fact that sizeof is not a function and so does not actually dereference the pointer even though it looks like it does. We can change it with a patch on top, but should then be changed everywhere in this file. > > + else > > hdr_padded_len = sizeof(struct padded_vnet_hdr); > > - } > > > > memcpy(hdr, p, hdr_len); > > > > Otherwise: > > Reviewed-by: Cornelia Huck