[PATCH tip 1/1] tracing: handle unregistering the current tracer

[Arnaldo Carvalho de Melo <acme@redhat.com>]

Impact: simplification

Instead of requiring that plugins have the sequence:

  my_tracer_stop(my_trace_array);
  unregister_tracer(my_tracer);

it should be possible just do a:

  unregister_tracer(my_tracer);

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 kernel/trace/trace.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ef4dbac..d247555 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -559,6 +559,15 @@ void unregister_tracer(struct tracer *type)
 
  found:
 	*t = (*t)->next;
+
+	if (type == current_trace && tracer_enabled) {
+		tracer_enabled = 0;
+		tracing_stop();
+		if (current_trace->stop)
+			current_trace->stop(&global_trace);
+		current_trace = &nop_trace;
+	}
+
 	if (strlen(type->name) != max_tracer_type_len)
 		goto out;
 
-- 
1.6.0.6