Commit 597af815 authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar
Browse files

function-graph: use int instead of atomic for ftrace_graph_active 



Impact: cleanup

The variable ftrace_graph_active is only modified under the
ftrace_lock mutex, thus an atomic is not necessary for modification.

Reported-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 5452af66

kernel/trace/ftrace.c

+7 −7
Original line number Diff line number Diff line
@@ -3092,7 +3092,7 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, 


#ifdef CONFIG_FUNCTION_GRAPH_TRACER



static atomic_t ftrace_graph_active;

static int ftrace_graph_active;

static struct notifier_block ftrace_suspend_notifier;



int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
@@ -3244,7 +3244,7 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, 
	mutex_lock(&ftrace_lock);



	/* we currently allow only one tracer registered at a time */

	if (atomic_read(&ftrace_graph_active)) {

	if (ftrace_graph_active) {

		ret = -EBUSY;

		goto out;

	}
@@ -3252,10 +3252,10 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, 
	ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;

	register_pm_notifier(&ftrace_suspend_notifier);



	atomic_inc(&ftrace_graph_active);

	ftrace_graph_active++;

	ret = start_graph_tracing();

	if (ret) {

		atomic_dec(&ftrace_graph_active);

		ftrace_graph_active--;

		goto out;

	}
@@ -3273,10 +3273,10 @@ void unregister_ftrace_graph(void) 
{

	mutex_lock(&ftrace_lock);



	if (!unlikely(atomic_read(&ftrace_graph_active)))

	if (unlikely(!ftrace_graph_active))

		goto out;



	atomic_dec(&ftrace_graph_active);

	ftrace_graph_active--;

	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);

	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;

	ftrace_graph_entry = ftrace_graph_entry_stub;
@@ -3290,7 +3290,7 @@ void unregister_ftrace_graph(void) 
/* Allocate a return stack for newly created task */

void ftrace_graph_init_task(struct task_struct *t)

{

	if (atomic_read(&ftrace_graph_active)) {

	if (ftrace_graph_active) {

		t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH

				* sizeof(struct ftrace_ret_stack),

				GFP_KERNEL);