tracing: Switch trace_stack.c code over to use guard()

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.

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/20241225222931.684913592@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 7f9572a373335a2971f572c831b06719f0bc985f..14c6f272c4d8a382070d45e1cf0ee97db38831c9 100644 (file)
--- 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;
 }