((dr->prod - dr->cons) & (ring_size - 1)) - 1);
}
+static inline u32 vio_dring_next(struct vio_dring_state *dr, u32 index)
+{
+ if (++index == dr->num_entries)
+ index = 0;
+ return index;
+}
+
+static inline u32 vio_dring_prev(struct vio_dring_state *dr, u32 index)
+{
+ if (index == 0)
+ return dr->num_entries - 1;
+ else
+ return index - 1;
+}
+
#define VIO_MAX_TYPE_LEN 32
#define VIO_MAX_COMPAT_LEN 64