[PATCH 13/14] tracing: Switch trace_stack.c code over to use guard()

[Steven Rostedt]

From: Steven Rostedt <rostedt@xxxxxxxxxxx>

The function stack_trace_sysctl() uses a goto on the error path to jump to
the mutex_unlock() code. Replace the logic to use guard() and let the
compiler worry about it.

Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
 kernel/trace/trace_osnoise.c | 2 +-
 kernel/trace/trace_stack.c   | 6 ++----
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
index b8626892c66d..b25c30b05dd0 100644
--- a/kernel/trace/trace_osnoise.c
+++ b/kernel/trace/trace_osnoise.c
@@ -2086,7 +2086,7 @@ static void osnoise_hotplug_workfn(struct work_struct *dummy)
 	guard(mutex)(&trace_types_lock);
 
 	if (!osnoise_has_registered_instances())
-		goto out_unlock_trace;
+		return;
 
 	guard(mutex)(&interface_lock);
 	guard(cpus_read_lock)();
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 7f9572a37333..14c6f272c4d8 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -520,20 +520,18 @@ stack_trace_sysctl(const struct ctl_table *table, int write, void *buffer,
 	int was_enabled;
 	int ret;
 
-	mutex_lock(&stack_sysctl_mutex);
+	guard(mutex)(&stack_sysctl_mutex);
 	was_enabled = !!stack_tracer_enabled;
 
 	ret = proc_dointvec(table, write, buffer, lenp, ppos);
 
 	if (ret || !write || (was_enabled == !!stack_tracer_enabled))
-		goto out;
+		return ret;
 
 	if (stack_tracer_enabled)
 		register_ftrace_function(&trace_ops);
 	else
 		unregister_ftrace_function(&trace_ops);
- out:
-	mutex_unlock(&stack_sysctl_mutex);
 	return ret;
 }
 
-- 
2.45.2