xen network backend driver

netback is the host side counterpart to the frontend driver in
drivers/net/xen-netfront.c. The PV protocol is also implemented by
frontend drivers in other OSes too, such as the BSDs and even Windows.

The patch is based on the driver from the xen.git pvops kernel tree but
has been put through the checkpatch.pl wringer plus several manual
cleanup passes and review iterations. The driver has been moved from
drivers/xen/netback to drivers/net/xen-netback.

One major change from xen.git is that the guest transmit path (i.e. what
looks like receive to netback) has been significantly reworked to remove
the dependency on the out of tree PageForeign page flag (a core kernel
patch which enables a per page destructor callback on the final
put_page). This page flag was used in order to implement a grant map
based transmit path (where guest pages are mapped directly into SKB
frags). Instead this version of netback uses grant copy operations into
regular memory belonging to the backend domain. Reinstating the grant
map functionality is something which I would like to revisit in the
future.

Note that this driver depends on 2e820f58f7ad "xen/irq: implement
bind_interdomain_evtchn_to_irqhandler for backend drivers" which is in
linux next via the "xen-two" tree and is intended for the 2.6.39 merge
window:
        git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git stable/backends
this branch has only that single commit since 2.6.38-rc2 and is safe for
cross merging into the net branch.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Reviewed-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 10 deletions

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 5b399b54fef7..5c8d9c385be0 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -359,7 +359,7 @@ static void xennet_tx_buf_gc(struct net_device *dev)
                         struct xen_netif_tx_response *txrsp;
 
                         txrsp = RING_GET_RESPONSE(&np->tx, cons);
-                        if (txrsp->status == NETIF_RSP_NULL)
+                        if (txrsp->status == XEN_NETIF_RSP_NULL)
                                 continue;
 
                         id  = txrsp->id;
@@ -416,7 +416,7 @@ static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
            larger than a page), split it it into page-sized chunks. */
         while (len > PAGE_SIZE - offset) {
                 tx->size = PAGE_SIZE - offset;
-                tx->flags |= NETTXF_more_data;
+                tx->flags |= XEN_NETTXF_more_data;
                 len -= tx->size;
                 data += tx->size;
                 offset = 0;
@@ -442,7 +442,7 @@ static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
         for (i = 0; i < frags; i++) {
                 skb_frag_t *frag = skb_shinfo(skb)->frags + i;
 
-                tx->flags |= NETTXF_more_data;
+                tx->flags |= XEN_NETTXF_more_data;
 
                 id = get_id_from_freelist(&np->tx_skb_freelist, np->tx_skbs);
                 np->tx_skbs[id].skb = skb_get(skb);
@@ -517,10 +517,10 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
         tx->flags = 0;
         if (skb->ip_summed == CHECKSUM_PARTIAL)
                 /* local packet? */
-                tx->flags |= NETTXF_csum_blank | NETTXF_data_validated;
+                tx->flags |= XEN_NETTXF_csum_blank | XEN_NETTXF_data_validated;
         else if (skb->ip_summed == CHECKSUM_UNNECESSARY)
                 /* remote but checksummed. */
-                tx->flags |= NETTXF_data_validated;
+                tx->flags |= XEN_NETTXF_data_validated;
 
         if (skb_shinfo(skb)->gso_size) {
                 struct xen_netif_extra_info *gso;
@@ -531,7 +531,7 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
                 if (extra)
                         extra->flags |= XEN_NETIF_EXTRA_FLAG_MORE;
                 else
-                        tx->flags |= NETTXF_extra_info;
+                        tx->flags |= XEN_NETTXF_extra_info;
 
                 gso->u.gso.size = skb_shinfo(skb)->gso_size;
                 gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
@@ -651,7 +651,7 @@ static int xennet_get_responses(struct netfront_info *np,
         int err = 0;
         unsigned long ret;
 
-        if (rx->flags & NETRXF_extra_info) {
+        if (rx->flags & XEN_NETRXF_extra_info) {
                 err = xennet_get_extras(np, extras, rp);
                 cons = np->rx.rsp_cons;
         }
@@ -688,7 +688,7 @@ static int xennet_get_responses(struct netfront_info *np,
                 __skb_queue_tail(list, skb);
 
 next:
-                if (!(rx->flags & NETRXF_more_data))
+                if (!(rx->flags & XEN_NETRXF_more_data))
                         break;
 
                 if (cons + frags == rp) {
@@ -983,9 +983,9 @@ err:
                 skb->truesize += skb->data_len - (RX_COPY_THRESHOLD - len);
                 skb->len += skb->data_len;
 
-                if (rx->flags & NETRXF_csum_blank)
+                if (rx->flags & XEN_NETRXF_csum_blank)
                         skb->ip_summed = CHECKSUM_PARTIAL;
-                else if (rx->flags & NETRXF_data_validated)
+                else if (rx->flags & XEN_NETRXF_data_validated)
                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 
                 __skb_queue_tail(&rxq, skb);