init private data

[lttng-ust.git] / libringbuffer / ring_buffer_frontend.c

diff --git a/libringbuffer/ring_buffer_frontend.c b/libringbuffer/ring_buffer_frontend.c
index 436e4b8c89981e5ebe7b2dffb679b43fbd521c54..6de8336861e4dadc43d77cf4f77140c54f67f64f 100644 (file)
--- a/libringbuffer/ring_buffer_frontend.c
+++ b/libringbuffer/ring_buffer_frontend.c
@@ -174,7 +174,7 @@ int lib_ring_buffer_create(struct lttng_ust_lib_ring_buffer *buf,
 {
        const struct lttng_ust_lib_ring_buffer_config *config = &chanb->config;
        struct channel *chan = caa_container_of(chanb, struct channel, backend);
-       void *priv = chanb->priv;
+       void *priv = channel_get_private(chan);
        unsigned int num_subbuf;
        size_t subbuf_header_size;
        u64 tsc;
@@ -409,7 +409,9 @@ static void channel_free(struct channel *chan, struct lttng_ust_shm_handle *hand
  * channel_create - Create channel.
  * @config: ring buffer instance configuration
  * @name: name of the channel
- * @priv: ring buffer client private data
+ * @priv_data: ring buffer client private data area pointer (output)
+ * @priv_data_size: length, in bytes, of the private data area.
+ * @priv_data_init: initialization data for private data.
  * @buf_addr: pointer the the beginning of the preallocated buffer contiguous
  *            address mapping. It is used only by RING_BUFFER_STATIC
  *            configuration. It can be set to NULL for other backends.
@@ -424,14 +426,18 @@ static void channel_free(struct channel *chan, struct lttng_ust_shm_handle *hand
  * Returns NULL on failure.
  */
 struct lttng_ust_shm_handle *channel_create(const struct lttng_ust_lib_ring_buffer_config *config,
-                  const char *name, void *priv, void *buf_addr,
-                  size_t subbuf_size,
+                  const char *name,
+                  void **priv_data,
+                  size_t priv_data_align,
+                  size_t priv_data_size,
+                  void *priv_data_init,
+                  void *buf_addr, size_t subbuf_size,
                   size_t num_subbuf, unsigned int switch_timer_interval,
                   unsigned int read_timer_interval,
                   int *shm_fd, int *wait_fd, uint64_t *memory_map_size)
 {
        int ret, cpu;
-       size_t shmsize;
+       size_t shmsize, chansize;
        struct channel *chan;
        struct lttng_ust_shm_handle *handle;
        struct shm_object *shmobj;
@@ -457,19 +463,38 @@ struct lttng_ust_shm_handle *channel_create(const struct lttng_ust_lib_ring_buff
                shmsize += sizeof(struct lttng_ust_lib_ring_buffer_shmp) * num_possible_cpus();
        else
                shmsize += sizeof(struct lttng_ust_lib_ring_buffer_shmp);
+       chansize = shmsize;
+       shmsize += offset_align(shmsize, priv_data_align);
+       shmsize += priv_data_size;
 
        shmobj = shm_object_table_append(handle->table, shmsize);
        if (!shmobj)
                goto error_append;
        /* struct channel is at object 0, offset 0 (hardcoded) */
-       set_shmp(handle->chan, zalloc_shm(shmobj, shmsize));
+       set_shmp(handle->chan, zalloc_shm(shmobj, chansize));
        assert(handle->chan._ref.index == 0);
        assert(handle->chan._ref.offset == 0);
        chan = shmp(handle, handle->chan);
        if (!chan)
                goto error_append;
 
-       ret = channel_backend_init(&chan->backend, name, config, priv,
+       /* space for private data */
+       if (priv_data_size) {
+               DECLARE_SHMP(void, priv_data_alloc);
+
+               align_shm(shmobj, priv_data_align);
+               chan->priv_data_offset = shmobj->allocated_len;
+               set_shmp(priv_data_alloc, zalloc_shm(shmobj, priv_data_size));
+               if (!shmp(handle, priv_data_alloc))
+                       goto error_append;
+               *priv_data = channel_get_private(chan);
+               memcpy(*priv_data, priv_data_init, priv_data_size);
+       } else {
+               chan->priv_data_offset = -1;
+               *priv_data = NULL;
+       }
+
+       ret = channel_backend_init(&chan->backend, name, config,
                                   subbuf_size, num_subbuf, handle);
        if (ret)
                goto error_backend_init;
@@ -570,19 +595,17 @@ void channel_release(struct channel *chan, struct lttng_ust_shm_handle *handle,
  * Call "destroy" callback, finalize channels, decrement the channel
  * reference count. Note that when readers have completed data
  * consumption of finalized channels, get_subbuf() will return -ENODATA.
- * They should release their handle at that point.  Returns the private
- * data pointer.
+ * They should release their handle at that point. 
  */
-void *channel_destroy(struct channel *chan, struct lttng_ust_shm_handle *handle,
+void channel_destroy(struct channel *chan, struct lttng_ust_shm_handle *handle,
                int shadow)
 {
        const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
-       void *priv;
        int cpu;
 
        if (shadow) {
                channel_release(chan, handle, shadow);
-               return NULL;
+               return;
        }
 
        channel_unregister_notifiers(chan, handle);
@@ -593,7 +616,7 @@ void *channel_destroy(struct channel *chan, struct lttng_ust_shm_handle *handle,
 
                        if (config->cb.buffer_finalize)
                                config->cb.buffer_finalize(buf,
-                                                          chan->backend.priv,
+                                                          channel_get_private(chan),
                                                           cpu, handle);
                        if (buf->backend.allocated)
                                lib_ring_buffer_switch_slow(buf, SWITCH_FLUSH,
@@ -609,7 +632,7 @@ void *channel_destroy(struct channel *chan, struct lttng_ust_shm_handle *handle,
                struct lttng_ust_lib_ring_buffer *buf = shmp(handle, chan->backend.buf[0].shmp);
 
                if (config->cb.buffer_finalize)
-                       config->cb.buffer_finalize(buf, chan->backend.priv, -1, handle);
+                       config->cb.buffer_finalize(buf, channel_get_private(chan), -1, handle);
                if (buf->backend.allocated)
                        lib_ring_buffer_switch_slow(buf, SWITCH_FLUSH,
                                                handle);
@@ -627,9 +650,8 @@ void *channel_destroy(struct channel *chan, struct lttng_ust_shm_handle *handle,
         * sessiond/consumer are keeping a reference on the shm file
         * descriptor directly. No need to refcount.
         */
-       priv = chan->backend.priv;
        channel_release(chan, handle, shadow);
-       return priv;
+       return;
 }
 
 struct lttng_ust_lib_ring_buffer *channel_get_ring_buffer(
@@ -1006,7 +1028,7 @@ void lib_ring_buffer_print_errors(struct channel *chan,
                                  struct lttng_ust_shm_handle *handle)
 {
        const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
-       void *priv = chan->backend.priv;
+       void *priv = channel_get_private(chan);
 
        ERRMSG("ring buffer %s, cpu %d: %lu records written, "
                          "%lu records overrun\n",