[rtla 07/13] rtla: Introduce timerlat_restart() helper

[Wander Lairson Costa <wander@redhat.com>]

The timerlat_hist and timerlat_top commands duplicate the logic for
handling threshold actions. When a threshold is reached, both commands
stop the trace, perform actions, and restart the trace if configured to
continue.

Create a new helper function, timerlat_restart(), to centralize this
shared logic and avoid code duplication. This function now handles the
threshold actions and restarts the necessary trace instances.

Refactor timerlat_hist_main() and the timerlat_top main loops to call
the new helper. This makes the code cleaner and more maintainable.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
---
 tools/tracing/rtla/src/timerlat.c      | 31 ++++++++++++++++++++++++++
 tools/tracing/rtla/src/timerlat.h      |  9 ++++++++
 tools/tracing/rtla/src/timerlat_hist.c | 19 ++++++++--------
 tools/tracing/rtla/src/timerlat_top.c  | 19 ++++++++--------
 4 files changed, 60 insertions(+), 18 deletions(-)

diff --git a/tools/tracing/rtla/src/timerlat.c b/tools/tracing/rtla/src/timerlat.c
index 56e0b8af041d7..50c7eb00fd6b7 100644
--- a/tools/tracing/rtla/src/timerlat.c
+++ b/tools/tracing/rtla/src/timerlat.c
@@ -22,6 +22,37 @@
 
 static int dma_latency_fd = -1;
 
+/**
+ * timerlat_restart - handle threshold actions and optionally restart tracing
+ * @tool: pointer to the osnoise_tool instance containing trace contexts
+ * @params: timerlat parameters with threshold action configuration
+ *
+ * Return:
+ *   RESTART_OK - Actions executed successfully and tracing restarted
+ *   RESTART_STOP - Actions executed but 'continue' flag not set, stop tracing
+ *   RESTART_ERROR - Failed to restart tracing after executing actions
+ */
+enum restart_result
+timerlat_restart(const struct osnoise_tool *tool, struct timerlat_params *params)
+{
+	actions_perform(&params->common.threshold_actions);
+
+	if (!params->common.threshold_actions.continue_flag)
+		/* continue flag not set, break */
+		return RESTART_STOP;
+
+	/* continue action reached, re-enable tracing */
+	if (tool->record && trace_instance_start(&tool->record->trace))
+		goto err;
+	if (tool->aa && trace_instance_start(&tool->aa->trace))
+		goto err;
+	return RESTART_OK;
+
+err:
+	err_msg("Error restarting trace\n");
+	return RESTART_ERROR;
+}
+
 /*
  * timerlat_apply_config - apply common configs to the initialized tool
  */
diff --git a/tools/tracing/rtla/src/timerlat.h b/tools/tracing/rtla/src/timerlat.h
index fd6065f48bb7f..47a34bb443fa0 100644
--- a/tools/tracing/rtla/src/timerlat.h
+++ b/tools/tracing/rtla/src/timerlat.h
@@ -31,6 +31,15 @@ struct timerlat_params {
 
 #define to_timerlat_params(ptr) container_of(ptr, struct timerlat_params, common)
 
+enum restart_result {
+	RESTART_OK,
+	RESTART_STOP,
+	RESTART_ERROR = -1,
+};
+
+enum restart_result
+timerlat_restart(const struct osnoise_tool *tool, struct timerlat_params *params);
+
 int timerlat_apply_config(struct osnoise_tool *tool, struct timerlat_params *params);
 int timerlat_main(int argc, char *argv[]);
 int timerlat_enable(struct osnoise_tool *tool);
diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c
index 09a3da3f58630..f14fc56c5b4a5 100644
--- a/tools/tracing/rtla/src/timerlat_hist.c
+++ b/tools/tracing/rtla/src/timerlat_hist.c
@@ -1165,18 +1165,19 @@ static int timerlat_hist_bpf_main_loop(struct osnoise_tool *tool)
 
 		if (!stop_tracing) {
 			/* Threshold overflow, perform actions on threshold */
-			actions_perform(&params->common.threshold_actions);
+			enum restart_result result;
 
-			if (!params->common.threshold_actions.continue_flag)
-				/* continue flag not set, break */
+			result = timerlat_restart(tool, params);
+			if (result == RESTART_STOP)
 				break;
 
-			/* continue action reached, re-enable tracing */
-			if (tool->record)
-				trace_instance_start(&tool->record->trace);
-			if (tool->aa)
-				trace_instance_start(&tool->aa->trace);
-			timerlat_bpf_restart_tracing();
+			if (result == RESTART_ERROR)
+				return -1;
+
+			if (timerlat_bpf_restart_tracing()) {
+				err_msg("Error restarting BPF trace\n");
+				return -1;
+			}
 		}
 	}
 	timerlat_bpf_detach();
diff --git a/tools/tracing/rtla/src/timerlat_top.c b/tools/tracing/rtla/src/timerlat_top.c
index 7679820e72db5..d831a9e1818f4 100644
--- a/tools/tracing/rtla/src/timerlat_top.c
+++ b/tools/tracing/rtla/src/timerlat_top.c
@@ -921,18 +921,19 @@ timerlat_top_bpf_main_loop(struct osnoise_tool *tool)
 
 		if (wait_retval == 1) {
 			/* Stopping requested by tracer */
-			actions_perform(&params->common.threshold_actions);
+			enum restart_result result;
 
-			if (!params->common.threshold_actions.continue_flag)
-				/* continue flag not set, break */
+			result = timerlat_restart(tool, params);
+			if (result == RESTART_STOP)
 				break;
 
-			/* continue action reached, re-enable tracing */
-			if (tool->record)
-				trace_instance_start(&tool->record->trace);
-			if (tool->aa)
-				trace_instance_start(&tool->aa->trace);
-			timerlat_bpf_restart_tracing();
+			if (result == RESTART_ERROR)
+				return -1;
+
+			if (timerlat_bpf_restart_tracing()) {
+				err_msg("Error restarting BPF trace\n");
+				return -1;
+			}
 		}
 
 		/* is there still any user-threads ? */
-- 
2.51.1