X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=src%2Fcommon%2Fkernel-consumer%2Fkernel-consumer.c;h=5334d13585842b0d63ab7f61d2b8cfa33e2b3b5e;hb=1ed0bc49572864c4b809b01eff37eefea6783927;hp=46a9f52c0ac2406787f2743213da3380b2a503d4;hpb=ee0350f8480addf9d786664e748645ab73a84565;p=lttng-tools.git

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 46a9f52c0..5334d1358 100644
--- 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 +1583,94 @@ 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.
+		 */
+		status = GET_NEXT_SUBBUFFER_STATUS_NO_DATA;
+		goto end;
+	default:
+		status = GET_NEXT_SUBBUFFER_STATUS_ERROR;
 		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 +1697,33 @@ 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