1.1 --- a/xen/include/public/io/ring.h	Wed Feb 24 10:59:37 2010 +0000
     1.2 +++ b/xen/include/public/io/ring.h	Wed Feb 24 11:03:56 2010 +0000
     1.3 @@ -50,6 +50,12 @@ typedef unsigned int RING_IDX;
     1.4   * A ring contains as many entries as will fit, rounded down to the nearest 
     1.5   * power of two (so we can mask with (size-1) to loop around).
     1.6   */
     1.7 +#define __CONST_RING_SIZE(_s, _sz) \
     1.8 +    (__RD32(((_sz) - offsetof(struct _s##_sring, ring)) / \
     1.9 +	    sizeof(((struct _s##_sring *)0)->ring[0])))
    1.10 +/*
    1.11 + * The same for passing in an actual pointer instead of a name tag.
    1.12 + */
    1.13  #define __RING_SIZE(_s, _sz) \
    1.14      (__RD32(((_sz) - (long)(_s)->ring + (long)(_s)) / sizeof((_s)->ring[0])))
    1.15  

     2.1 --- a/xen/include/public/io/usbif.h	Wed Feb 24 10:59:37 2010 +0000
     2.2 +++ b/xen/include/public/io/usbif.h	Wed Feb 24 11:03:56 2010 +0000
     2.3 @@ -128,7 +128,7 @@ struct usbif_urb_response {
     2.4  typedef struct usbif_urb_response usbif_urb_response_t;
     2.5  
     2.6  DEFINE_RING_TYPES(usbif_urb, struct usbif_urb_request, struct usbif_urb_response);
     2.7 -#define USB_URB_RING_SIZE __RING_SIZE((struct usbif_urb_sring *)0, PAGE_SIZE)
     2.8 +#define USB_URB_RING_SIZE __CONST_RING_SIZE(usbif_urb, PAGE_SIZE)
     2.9  
    2.10  /*
    2.11   * RING for notifying connect/disconnect events to frontend
    2.12 @@ -146,6 +146,6 @@ struct usbif_conn_response {
    2.13  typedef struct usbif_conn_response usbif_conn_response_t;
    2.14  
    2.15  DEFINE_RING_TYPES(usbif_conn, struct usbif_conn_request, struct usbif_conn_response);
    2.16 -#define USB_CONN_RING_SIZE __RING_SIZE((struct usbif_conn_sring *)0, PAGE_SIZE)
    2.17 +#define USB_CONN_RING_SIZE __CONST_RING_SIZE(usbif_conn, PAGE_SIZE)
    2.18  
    2.19  #endif /* __XEN_PUBLIC_IO_USBIF_H__ */