From 012873d057a449c4480e7679e733a7daa9aa540f Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Fri, 24 Oct 2014 16:55:57 +0300 Subject: [PATCH] virtio_net: get rid of virtio_net_hdr/skb_vnet_hdr 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 Reviewed-by: Cornelia Huck Reviewed-by: Jason Wang --- drivers/net/virtio_net.c | 90 ++++++++++++++++++++++-------------------------- 1 file changed, 41 insertions(+), 49 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 1630c21..516f2cb 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -123,6 +123,9 @@ struct virtnet_info { /* Host can handle any s/g split between our header and packet data */ bool any_header_sg; + /* Packet virtio header size */ + u8 hdr_len; + /* Active statistics */ struct virtnet_stats __percpu *stats; @@ -139,21 +142,14 @@ struct virtnet_info { struct notifier_block nb; }; -struct skb_vnet_hdr { - union { - struct virtio_net_hdr hdr; - struct virtio_net_hdr_mrg_rxbuf mhdr; - }; -}; - struct padded_vnet_hdr { - struct virtio_net_hdr hdr; + struct virtio_net_hdr_mrg_rxbuf hdr; /* - * virtio_net_hdr should be in a separated sg buffer because of a - * QEMU bug, and data sg buffer shares same page with this header sg. - * This padding makes next sg 16 byte aligned after virtio_net_hdr. + * hdr is in a separate sg buffer, and data sg buffer shares same page + * with this header sg. This padding makes next sg 16 byte aligned + * after the header. */ - char padding[6]; + char padding[4]; }; /* Converting between virtqueue no. and kernel tx/rx queue no. @@ -179,9 +175,9 @@ static int rxq2vq(int rxq) return rxq * 2; } -static inline struct skb_vnet_hdr *skb_vnet_hdr(struct sk_buff *skb) +static inline struct virtio_net_hdr_mrg_rxbuf *skb_vnet_hdr(struct sk_buff *skb) { - return (struct skb_vnet_hdr *)skb->cb; + return (struct virtio_net_hdr_mrg_rxbuf *)skb->cb; } /* @@ -247,7 +243,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, unsigned int len, unsigned int truesize) { struct sk_buff *skb; - struct skb_vnet_hdr *hdr; + struct virtio_net_hdr_mrg_rxbuf *hdr; unsigned int copy, hdr_len, hdr_padded_len; char *p; @@ -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; + else hdr_padded_len = sizeof(struct padded_vnet_hdr); - } memcpy(hdr, p, hdr_len); @@ -317,11 +311,11 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi, return skb; } -static struct sk_buff *receive_small(void *buf, unsigned int len) +static struct sk_buff *receive_small(struct virtnet_info *vi, void *buf, unsigned int len) { struct sk_buff * skb = buf; - len -= sizeof(struct virtio_net_hdr); + len -= vi->hdr_len; skb_trim(skb, len); return skb; @@ -354,8 +348,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, unsigned int len) { void *buf = mergeable_ctx_to_buf_address(ctx); - struct skb_vnet_hdr *hdr = buf; - u16 num_buf = virtio16_to_cpu(rq->vq->vdev, hdr->mhdr.num_buffers); + struct virtio_net_hdr_mrg_rxbuf *hdr = buf; + u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers); struct page *page = virt_to_head_page(buf); int offset = buf - page_address(page); unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx)); @@ -373,8 +367,8 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, if (unlikely(!ctx)) { pr_debug("%s: rx error: %d buffers out of %d missing\n", dev->name, num_buf, - virtio16_to_cpu(rq->vq->vdev, - hdr->mhdr.num_buffers)); + virtio16_to_cpu(vi->vdev, + hdr->num_buffers)); dev->stats.rx_length_errors++; goto err_buf; } @@ -441,7 +435,7 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq, struct net_device *dev = vi->dev; struct virtnet_stats *stats = this_cpu_ptr(vi->stats); struct sk_buff *skb; - struct skb_vnet_hdr *hdr; + struct virtio_net_hdr_mrg_rxbuf *hdr; if (unlikely(len < sizeof(struct virtio_net_hdr) + ETH_HLEN)) { pr_debug("%s: short packet %i\n", dev->name, len); @@ -463,7 +457,7 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq, else if (vi->big_packets) skb = receive_big(dev, vi, rq, buf, len); else - skb = receive_small(buf, len); + skb = receive_small(vi, buf, len); if (unlikely(!skb)) return; @@ -545,7 +539,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq, gfp_t gfp) { struct sk_buff *skb; - struct skb_vnet_hdr *hdr; + struct virtio_net_hdr_mrg_rxbuf *hdr; int err; skb = __netdev_alloc_skb_ip_align(vi->dev, GOOD_PACKET_LEN, gfp); @@ -556,7 +550,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq, hdr = skb_vnet_hdr(skb); sg_init_table(rq->sg, MAX_SKB_FRAGS + 2); - sg_set_buf(rq->sg, &hdr->hdr, sizeof hdr->hdr); + sg_set_buf(rq->sg, hdr, vi->hdr_len); skb_to_sgvec(skb, rq->sg + 1, 0, skb->len); err = virtqueue_add_inbuf(rq->vq, rq->sg, 2, skb, gfp); @@ -566,7 +560,8 @@ static int add_recvbuf_small(struct virtnet_info *vi, struct receive_queue *rq, return err; } -static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp) +static int add_recvbuf_big(struct virtnet_info *vi, struct receive_queue *rq, + gfp_t gfp) { struct page *first, *list = NULL; char *p; @@ -597,8 +592,8 @@ static int add_recvbuf_big(struct receive_queue *rq, gfp_t gfp) p = page_address(first); /* rq->sg[0], rq->sg[1] share the same page */ - /* a separated rq->sg[0] for virtio_net_hdr only due to QEMU bug */ - sg_set_buf(&rq->sg[0], p, sizeof(struct virtio_net_hdr)); + /* a separated rq->sg[0] for header - required in case !any_header_sg */ + sg_set_buf(&rq->sg[0], p, vi->hdr_len); /* rq->sg[1] for data packet, from offset */ offset = sizeof(struct padded_vnet_hdr); @@ -677,7 +672,7 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq, if (vi->mergeable_rx_bufs) err = add_recvbuf_mergeable(rq, gfp); else if (vi->big_packets) - err = add_recvbuf_big(rq, gfp); + err = add_recvbuf_big(vi, rq, gfp); else err = add_recvbuf_small(vi, rq, gfp); @@ -857,18 +852,14 @@ static void free_old_xmit_skbs(struct send_queue *sq) static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) { - struct skb_vnet_hdr *hdr; + struct virtio_net_hdr_mrg_rxbuf *hdr; const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest; struct virtnet_info *vi = sq->vq->vdev->priv; unsigned num_sg; - unsigned hdr_len; + unsigned hdr_len = vi->hdr_len; bool can_push; pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest); - if (vi->mergeable_rx_bufs) - hdr_len = sizeof hdr->mhdr; - else - hdr_len = sizeof hdr->hdr; can_push = vi->any_header_sg && !((unsigned long)skb->data & (__alignof__(*hdr) - 1)) && @@ -876,7 +867,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) /* Even if we can, don't push here yet as this would skew * csum_start offset below. */ if (can_push) - hdr = (struct skb_vnet_hdr *)(skb->data - hdr_len); + hdr = (struct virtio_net_hdr_mrg_rxbuf *)(skb->data - hdr_len); else hdr = skb_vnet_hdr(skb); @@ -909,7 +900,7 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb) } if (vi->mergeable_rx_bufs) - hdr->mhdr.num_buffers = 0; + hdr->num_buffers = 0; sg_init_table(sq->sg, MAX_SKB_FRAGS + 2); if (can_push) { @@ -1814,18 +1805,19 @@ static int virtnet_probe(struct virtio_device *vdev) if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) vi->mergeable_rx_bufs = true; + if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF)) + vi->hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf); + else + vi->hdr_len = sizeof(struct virtio_net_hdr); + if (virtio_has_feature(vdev, VIRTIO_F_ANY_LAYOUT)) vi->any_header_sg = true; if (virtio_has_feature(vdev, VIRTIO_NET_F_CTRL_VQ)) vi->has_cvq = true; - if (vi->any_header_sg) { - if (vi->mergeable_rx_bufs) - dev->needed_headroom = sizeof(struct virtio_net_hdr_mrg_rxbuf); - else - dev->needed_headroom = sizeof(struct virtio_net_hdr); - } + if (vi->any_header_sg) + dev->needed_headroom = vi->hdr_len; /* Use single tx/rx queue pair as default */ vi->curr_queue_pairs = 1; -- 2.7.4