Commit 2167ca02 authored by Ross Lagerwall's avatar Ross Lagerwall Committed by David S. Miller
Browse files

xen/netback: add fraglist support for to-guest rx 



This allows full 64K skbuffs (with 1500 mtu ethernet, composed of 45
fragments) to be handled by netback for to-guest rx.

Signed-off-by: default avatarRoss Lagerwall <ross.lagerwall@citrix.com>
[re-based]
Signed-off-by: default avatarPaul Durrant <paul.durrant@citrix.com>
Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a37f1229

drivers/net/xen-netback/interface.c

+1 −1
Original line number Diff line number Diff line
@@ -467,7 +467,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid, 
	dev->netdev_ops	= &xenvif_netdev_ops;

	dev->hw_features = NETIF_F_SG |

		NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |

		NETIF_F_TSO | NETIF_F_TSO6;

		NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_FRAGLIST;

	dev->features = dev->hw_features | NETIF_F_RXCSUM;

	dev->ethtool_ops = &xenvif_ethtool_ops;

drivers/net/xen-netback/rx.c

+29 −9
Original line number Diff line number Diff line
@@ -215,7 +215,8 @@ static unsigned int xenvif_gso_type(struct sk_buff *skb) 
struct xenvif_pkt_state {

	struct sk_buff *skb;

	size_t remaining_len;

	int frag; /* frag == -1 => skb->head */

	struct sk_buff *frag_iter;

	int frag; /* frag == -1 => frag_iter->head */

	unsigned int frag_offset;

	struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX - 1];

	unsigned int extra_count;
@@ -237,6 +238,7 @@ static void xenvif_rx_next_skb(struct xenvif_queue *queue, 
	memset(pkt, 0, sizeof(struct xenvif_pkt_state));



	pkt->skb = skb;

	pkt->frag_iter = skb;

	pkt->remaining_len = skb->len;

	pkt->frag = -1;
@@ -293,20 +295,40 @@ static void xenvif_rx_complete(struct xenvif_queue *queue, 
	__skb_queue_tail(queue->rx_copy.completed, pkt->skb);

}



static void xenvif_rx_next_frag(struct xenvif_pkt_state *pkt)

{

	struct sk_buff *frag_iter = pkt->frag_iter;

	unsigned int nr_frags = skb_shinfo(frag_iter)->nr_frags;



	pkt->frag++;

	pkt->frag_offset = 0;



	if (pkt->frag >= nr_frags) {

		if (frag_iter == pkt->skb)

			pkt->frag_iter = skb_shinfo(frag_iter)->frag_list;

		else

			pkt->frag_iter = frag_iter->next;



		pkt->frag = -1;

	}

}



static void xenvif_rx_next_chunk(struct xenvif_queue *queue,

				 struct xenvif_pkt_state *pkt,

				 unsigned int offset, void **data,

				 size_t *len)

{

	struct sk_buff *skb = pkt->skb;

	struct sk_buff *frag_iter = pkt->frag_iter;

	void *frag_data;

	size_t frag_len, chunk_len;



	BUG_ON(!frag_iter);



	if (pkt->frag == -1) {

		frag_data = skb->data;

		frag_len = skb_headlen(skb);

		frag_data = frag_iter->data;

		frag_len = skb_headlen(frag_iter);

	} else {

		skb_frag_t *frag = &skb_shinfo(skb)->frags[pkt->frag];

		skb_frag_t *frag = &skb_shinfo(frag_iter)->frags[pkt->frag];



		frag_data = skb_frag_address(frag);

		frag_len = skb_frag_size(frag);
@@ -322,10 +344,8 @@ static void xenvif_rx_next_chunk(struct xenvif_queue *queue, 
	pkt->frag_offset += chunk_len;



	/* Advance to next frag? */

	if (frag_len == chunk_len) {

		pkt->frag++;

		pkt->frag_offset = 0;

	}

	if (frag_len == chunk_len)

		xenvif_rx_next_frag(pkt);



	*data = frag_data;

	*len = chunk_len;

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