+ /*
+ * The field ctx_len is the length of struct
+ * lttng_ust_lib_ring_buffer_ctx as known by the user of
+ * lib_ring_buffer_ctx_init.
+ */
+ unsigned int ctx_len;
+ void *ip; /* caller ip address */
+ void *priv2; /* 2nd priv data */
+ char padding2[LTTNG_UST_RING_BUFFER_CTX_PADDING];
+ /*
+ * This is the end of the initial fields expected by the original ABI
+ * between probes and UST. Only the fields above can be used if
+ * ctx_len is 0. Use the value of ctx_len to find out which of the
+ * following fields may be used.
+ */
+ struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;