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: Ross Lagerwall <ross.lagerwall@citrix.com>
[re-based]
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
index 8c8c5b5..8e9ade6 100644
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -215,7 +215,8 @@
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 @@
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 @@
__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 @@
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;