From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: [PATCH 4/4] virtio: net: Allow receiving SG packets Date: Tue, 29 Apr 2008 01:21:03 +1000 Message-ID: <200804290121.04384.rusty@rustcorp.com.au> References: <200804290116.05951.rusty@rustcorp.com.au> <200804290117.45010.rusty@rustcorp.com.au> <200804290119.17180.rusty@rustcorp.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, Herbert Xu To: virtualization@lists.linux-foundation.org Return-path: Received: from ozlabs.org ([203.10.76.45]:60044 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932306AbYD1PYJ (ORCPT ); Mon, 28 Apr 2008 11:24:09 -0400 In-Reply-To: <200804290119.17180.rusty@rustcorp.com.au> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: Date: Fri, 18 Apr 2008 11:24:27 +0800 From: Herbert Xu Finally this patch lets virtio_net receive GSO packets in addition to sending them. This can definitely be optimised for the non-GSO case. For comparison the Xen approach stores one page in each skb and uses subsequent skb's pages to construct an SG skb instead of preallocating the maximum amount of pages per skb. Signed-off-by: Rusty Russell (added feature bits) --- drivers/net/virtio_net.c | 40 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 36 insertions(+), 4 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -77,6 +77,7 @@ static void receive_skb(struct net_devic unsigned len) { struct virtio_net_hdr *hdr = skb_vnet_hdr(skb); + int err; if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) { pr_debug("%s: short packet %i\n", dev->name, len); @@ -84,9 +85,15 @@ static void receive_skb(struct net_devic goto drop; } len -= sizeof(struct virtio_net_hdr); - BUG_ON(len > MAX_PACKET_LEN); - skb_trim(skb, len); + err = pskb_trim(skb, len); + if (err) { + pr_debug("%s: pskb_trim failed %i %d\n", dev->name, len, err); + dev->stats.rx_dropped++; + goto drop; + } + skb->truesize += skb->data_len; + skb->protocol = eth_type_trans(skb, dev); pr_debug("Receiving skb proto 0x%04x len %i type %i\n", ntohs(skb->protocol), skb->len, skb->pkt_type); @@ -147,7 +154,7 @@ static void try_fill_recv(struct virtnet { struct sk_buff *skb; struct scatterlist sg[2+MAX_SKB_FRAGS]; - int num, err; + int num, err, i; sg_init_table(sg, 2+MAX_SKB_FRAGS); for (;;) { @@ -157,6 +164,24 @@ static void try_fill_recv(struct virtnet skb_put(skb, MAX_PACKET_LEN); vnet_hdr_to_sg(sg, skb); + + if (vi->dev->features & NETIF_F_LRO) { + for (i = 0; i < MAX_SKB_FRAGS; i++) { + skb_frag_t *f = &skb_shinfo(skb)->frags[i]; + f->page = alloc_page(GFP_ATOMIC); + if (!f->page) + break; + + f->page_offset = 0; + f->size = PAGE_SIZE; + + skb->data_len += PAGE_SIZE; + skb->len += PAGE_SIZE; + + skb_shinfo(skb)->nr_frags++; + } + } + num = skb_to_sgvec(skb, sg+1, 0, skb->len) + 1; skb_queue_head(&vi->recv, skb); @@ -411,6 +436,12 @@ static int virtnet_probe(struct virtio_d dev->features |= NETIF_F_UFO; } + /* If we can receive ANY GSO packets, we must allocate large ones. */ + if (virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO4) + || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_TSO6) + || virtio_has_feature(vdev, VIRTIO_NET_F_GUEST_ECN)) + dev->features |= NETIF_F_LRO; + /* Configuration may specify what MAC to use. Otherwise random. */ if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) { vdev->config->get(vdev, @@ -504,7 +535,8 @@ static unsigned int features[] = { static unsigned int features[] = { VIRTIO_NET_F_CSUM, VIRTIO_NET_F_GSO, VIRTIO_NET_F_MAC, VIRTIO_NET_F_HOST_TSO4, VIRTIO_NET_F_HOST_UFO, VIRTIO_NET_F_HOST_TSO6, - VIRTIO_NET_F_HOST_ECN, + VIRTIO_NET_F_HOST_ECN, VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6, + VIRTIO_NET_F_GUEST_ECN, /* We don't yet handle UFO input. */ }; static struct virtio_driver virtio_net = {