1 files changed, 13 insertions, 6 deletions

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 08ae01b41c83..c47794b9d42f 100644
--- 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;
@@ -143,13 +150,13 @@ struct xenvif {
          */
         RING_IDX rx_req_cons_peek;
 
-        /* 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];