Clean-up: consumerd: use a specific status code for get_next_subbuffer

[lttng-tools.git] / src / common / kernel-consumer / kernel-consumer.c

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 4f734294caa553477f46eb0858edc45b3476b1e9..8c0a87737056e4e2e39fa6adadbeb7bccb4305bc 100644 (file)
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -403,16 +403,12 @@ static int lttng_kconsumer_snapshot_metadata(
 
                ret_read = lttng_consumer_read_subbuffer(metadata_stream, ctx, true);
                if (ret_read < 0) {
-                       if (ret_read != -EAGAIN) {
-                               ERR("Kernel snapshot reading metadata subbuffer (ret: %zd)",
-                                               ret_read);
-                               ret = ret_read;
-                               goto error_snapshot;
-                       }
-                       /* ret_read is negative at this point so we will exit the loop. */
-                       continue;
+                       ERR("Kernel snapshot reading metadata subbuffer (ret: %zd)",
+                                       ret_read);
+                       ret = ret_read;
+                       goto error_snapshot;
                }
-       } while (ret_read >= 0);
+       } while (ret_read > 0);
 
        if (use_relayd) {
                close_relayd_stream(metadata_stream);
@@ -1587,68 +1583,101 @@ end:
 }
 
 static
-int get_subbuffer_common(struct lttng_consumer_stream *stream,
+enum get_next_subbuffer_status get_subbuffer_common(
+               struct lttng_consumer_stream *stream,
                struct stream_subbuffer *subbuffer)
 {
        int ret;
+       enum get_next_subbuffer_status status;
 
        ret = kernctl_get_next_subbuf(stream->wait_fd);
-       if (ret) {
+       switch (ret) {
+       case 0:
+               status = GET_NEXT_SUBBUFFER_STATUS_OK;
+               break;
+       case -ENODATA:
+               case -EAGAIN:
+               /*
+                * The caller only expects -ENODATA when there is no data to
+                * read, but the kernel tracer returns -EAGAIN when there is
+                * currently no data for a non-finalized stream, and -ENODATA
+                * when there is no data for a finalized stream. Those can be
+                * combined into a -ENODATA return value.
+                */
+<<<<<<< HEAD
+               if (ret == -EAGAIN) {
+                       ret = -ENODATA;
+               }
+
+=======
+               status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
+               goto end;
+       default:
+               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
+>>>>>>> ba6c36321 (Clean-up: consumerd: use a specific status code for get_next_subbuffer)
                goto end;
        }
 
        ret = stream->read_subbuffer_ops.extract_subbuffer_info(
-                       stream, subbuffer);
+               stream, subbuffer);
+       if (ret) {
+               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
+       }
 end:
-       return ret;
+       return status;
 }
 
 static
-int get_next_subbuffer_splice(struct lttng_consumer_stream *stream,
+enum get_next_subbuffer_status get_next_subbuffer_splice(
+               struct lttng_consumer_stream *stream,
                struct stream_subbuffer *subbuffer)
 {
-       int ret;
+       const enum get_next_subbuffer_status status =
+                       get_subbuffer_common(stream, subbuffer);
 
-       ret = get_subbuffer_common(stream, subbuffer);
-       if (ret) {
+       if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
                goto end;
        }
 
        subbuffer->buffer.fd = stream->wait_fd;
 end:
-       return ret;
+       return status;
 }
 
 static
-int get_next_subbuffer_mmap(struct lttng_consumer_stream *stream,
+enum get_next_subbuffer_status get_next_subbuffer_mmap(
+               struct lttng_consumer_stream *stream,
                struct stream_subbuffer *subbuffer)
 {
        int ret;
+       enum get_next_subbuffer_status status;
        const char *addr;
 
-       ret = get_subbuffer_common(stream, subbuffer);
-       if (ret) {
+       status = get_subbuffer_common(stream, subbuffer);
+       if (status != GET_NEXT_SUBBUFFER_STATUS_OK) {
                goto end;
        }
 
        ret = get_current_subbuf_addr(stream, &addr);
        if (ret) {
+               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
                goto end;
        }
 
        subbuffer->buffer.buffer = lttng_buffer_view_init(
                        addr, 0, subbuffer->info.data.padded_subbuf_size);
 end:
-       return ret;
+       return status;
 }
 
 static
-int get_next_subbuffer_metadata_check(struct lttng_consumer_stream *stream,
+enum get_next_subbuffer_status get_next_subbuffer_metadata_check(struct lttng_consumer_stream *stream,
                struct stream_subbuffer *subbuffer)
 {
        int ret;
        const char *addr;
        bool coherent;
+       enum get_next_subbuffer_status status;
 
        ret = kernctl_get_next_subbuf_metadata_check(stream->wait_fd,
                        &coherent);
@@ -1675,7 +1704,33 @@ int get_next_subbuffer_metadata_check(struct lttng_consumer_stream *stream,
                        subbuffer->info.metadata.padded_subbuf_size,
                        coherent ? "true" : "false");
 end:
-       return ret;
+       /*
+        * The caller only expects -ENODATA when there is no data to read, but
+        * the kernel tracer returns -EAGAIN when there is currently no data
+        * for a non-finalized stream, and -ENODATA when there is no data for a
+        * finalized stream. Those can be combined into a -ENODATA return value.
+        */
+       switch (ret) {
+       case 0:
+               status = GET_NEXT_SUBBUFFER_STATUS_OK;
+               break;
+       case -ENODATA:
+       case -EAGAIN:
+               /*
+                * The caller only expects -ENODATA when there is no data to
+                * read, but the kernel tracer returns -EAGAIN when there is
+                * currently no data for a non-finalized stream, and -ENODATA
+                * when there is no data for a finalized stream. Those can be
+                * combined into a -ENODATA return value.
+                */
+               status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
+               break;
+       default:
+               status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
+               break;
+       }
+
+       return status;
 }
 
 static
@@ -1710,6 +1765,14 @@ bool is_get_next_check_metadata_available(int tracer_fd)
        return available;
 }
 
+static
+int signal_metadata(struct lttng_consumer_stream *stream,
+               struct lttng_consumer_local_data *ctx)
+{
+       ASSERT_LOCKED(stream->metadata_rdv_lock);
+       return pthread_cond_broadcast(&stream->metadata_rdv) ? -errno : 0;
+}
+
 static
 int lttng_kconsumer_set_stream_ops(
                struct lttng_consumer_stream *stream)
@@ -1740,6 +1803,8 @@ int lttng_kconsumer_set_stream_ops(
                        metadata_bucket_destroy(stream->metadata_bucket);
                        stream->metadata_bucket = NULL;
                }
+
+               stream->read_subbuffer_ops.on_sleep = signal_metadata;
        }
 
        if (!stream->read_subbuffer_ops.get_next_subbuffer) {