fgraph: Have set_graph_notrace only affect function_graph tracer

In order to make the function graph infrastructure more generic, there can
not be code specific for the function_graph tracer in the generic code. This
includes the set_graph_notrace logic, that stops all graph calls when a
function in the set_graph_notrace is hit.

By using the trace_recursion mask, we can use a bit in the current
task_struct to implement the notrace code, and move the logic out of
fgraph.c and into trace_functions_graph.c and keeps it affecting only the
tracer and not all call graph callbacks.

Acked-by: Namhyung Kim <namhyung@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

1 files changed, 22 insertions, 0 deletions

diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index b846d82c2f95..ecf543df943b 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -188,6 +188,18 @@ int trace_graph_entry(struct ftrace_graph_ent *trace)
 	int cpu;
 	int pc;
 
+	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT))
+		return 0;
+
+	if (ftrace_graph_notrace_addr(trace->func)) {
+		trace_recursion_set(TRACE_GRAPH_NOTRACE_BIT);
+		/*
+		 * Need to return 1 to have the return called
+		 * that will clear the NOTRACE bit.
+		 */
+		return 1;
+	}
+
 	if (!ftrace_trace_task(tr))
 		return 0;
 
@@ -290,6 +302,11 @@ void trace_graph_return(struct ftrace_graph_ret *trace)
 
 	ftrace_graph_addr_finish(trace);
 
+	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
+		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
+		return;
+	}
+
 	local_irq_save(flags);
 	cpu = raw_smp_processor_id();
 	data = per_cpu_ptr(tr->trace_buffer.data, cpu);
@@ -315,6 +332,11 @@ static void trace_graph_thresh_return(struct ftrace_graph_ret *trace)
 {
 	ftrace_graph_addr_finish(trace);
 
+	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
+		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
+		return;
+	}
+
 	if (tracing_thresh &&
 	    (trace->rettime - trace->calltime < tracing_thresh))
 		return;