Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

[~andy/linux] / drivers / net / xen-netback / common.h

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index ba30a6d9fefabf225631b731a1ce0fc73ea7653d..c955fc39d69ab6da7f20bae989d39ca0bc77be1e 100644 (file)
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -101,6 +101,13 @@ struct xenvif_rx_meta {
 
 #define MAX_PENDING_REQS 256
 
+/* It's possible for an skb to have a maximal number of frags
+ * but still be less than MAX_BUFFER_OFFSET in size. Thus the
+ * worst-case number of copy operations is MAX_SKB_FRAGS per
+ * ring slot.
+ */
+#define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)
+
 struct xenvif {
        /* Unique identifier for this interface. */
        domid_t          domid;
@@ -141,13 +148,13 @@ struct xenvif {
         */
        bool rx_event;
 
-       /* Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
-        * head/fragment page uses 2 copy operations because it
-        * straddles two buffers in the frontend.
-        */
-       struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
-       struct xenvif_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
+       /* This array is allocated seperately as it is large */
+       struct gnttab_copy *grant_copy_op;
 
+       /* We create one meta structure per ring request we consume, so
+        * the maximum number is the same as the ring size.
+        */
+       struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
 
        u8               fe_dev_addr[6];