Calculate context length outside of retry loop

[lttng-ust.git] / include / lttng / ringbuffer-config.h

diff --git a/include/lttng/ringbuffer-config.h b/include/lttng/ringbuffer-config.h
index 5ae0d8a6a4985500e168ab0e529b8642f0cba554..421a8637c5ca8fec432f3aa219527cdba12c92b6 100644 (file)
--- a/include/lttng/ringbuffer-config.h
+++ b/include/lttng/ringbuffer-config.h
@@ -57,7 +57,8 @@ struct lttng_ust_lib_ring_buffer_client_cb {
        size_t (*record_header_size) (const struct lttng_ust_lib_ring_buffer_config *config,
                                      struct channel *chan, size_t offset,
                                      size_t *pre_header_padding,
-                                     struct lttng_ust_lib_ring_buffer_ctx *ctx);
+                                     struct lttng_ust_lib_ring_buffer_ctx *ctx,
+                                     void *client_ctx);
 
        /* Slow path only, at subbuffer switch */
        size_t (*subbuffer_header_size) (void);
@@ -256,10 +257,22 @@ struct lttng_ust_lib_ring_buffer_ctx {
                                         */
        uint64_t tsc;                   /* time-stamp counter value */
        unsigned int rflags;            /* reservation flags */
-       unsigned int padding1;          /* padding to realign on pointer */
+       /*
+        * 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;
 };
 
 /**
@@ -291,7 +304,7 @@ void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
        ctx->cpu = cpu;
        ctx->rflags = 0;
        ctx->handle = handle;
-       ctx->padding1 = 0;
+       ctx->ctx_len = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
        ctx->ip = 0;
        ctx->priv2 = priv2;
        memset(ctx->padding2, 0, LTTNG_UST_RING_BUFFER_CTX_PADDING);