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Commit 012873d0 authored by Michael S. Tsirkin's avatar Michael S. Tsirkin
Browse files

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: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarCornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: default avatarJason Wang <jasowang@redhat.com>
parent 946fa564

drivers/net/virtio_net.c

+41 −49
Original line number Diff line number Diff line
@@ -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;