xen-netback: Move grant_copy_op array back into struct xenvif.

This array was allocated separately in commit ac3d5ac2 ("xen-netback:
fix guest-receive-side array sizes") due to it being very large, and a
struct xenvif is allocated as the netdev_priv part of a struct
net_device, i.e. via kmalloc() but falling back to vmalloc() if the
initial alloc. fails.

In preparation for the multi-queue patches, where this array becomes
part of struct xenvif_queue and is always allocated through vzalloc(),
move this back into the struct xenvif.
Signed-off-by: NAndrew J. Bennieston <andrew.bennieston@citrix.com>
Acked-by: NWei Liu <wei.liu2@citrix.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/xen-netback/common.h

@@ -158,8 +158,7 @@ struct xenvif {
 
 	struct timer_list wake_queue;
 
-	/* This array is allocated seperately as it is large */
-	struct gnttab_copy *grant_copy_op;
+	struct gnttab_copy grant_copy_op[MAX_GRANT_COPY_OPS];
 
 	/* We create one meta structure per ring request we consume, so
 	 * the maximum number is the same as the ring size.

drivers/net/xen-netback/interface.c

@@ -334,14 +334,6 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
 
 	vif = netdev_priv(dev);
 
-	vif->grant_copy_op = vmalloc(sizeof(struct gnttab_copy) *
-				     MAX_GRANT_COPY_OPS);
-	if (vif->grant_copy_op == NULL) {
-		pr_warn("Could not allocate grant copy space for %s\n", name);
-		free_netdev(dev);
-		return ERR_PTR(-ENOMEM);
-	}
-
 	vif->domid  = domid;
 	vif->handle = handle;
 	vif->can_sg = 1;
@@ -601,7 +593,6 @@ void xenvif_free(struct xenvif *vif)
 
 	unregister_netdev(vif->dev);
 
-	vfree(vif->grant_copy_op);
 	free_netdev(vif->dev);
 
 	module_put(THIS_MODULE);