[PATCH 3/6] tracing/kprobe: Adopt guard() and scoped_guard()

[Masami Hiramatsu (Google)]

From: Masami Hiramatsu (Google) <mhira...@kernel.org>

Use guard() or scoped_guard() in kprobe events for critical sections
rather than discrete lock/unlock pairs.

Signed-off-by: Masami Hiramatsu (Google) <mhira...@kernel.org>
---
 kernel/trace/trace_kprobe.c |   18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 263fac44d3ca..bae26eb14449 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -634,7 +634,7 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
        struct trace_kprobe *old_tk;
        int ret;
 
-       mutex_lock(&event_mutex);
+       guard(mutex)(&event_mutex);
 
        old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
                                   trace_probe_group_name(&tk->tp));
@@ -642,11 +642,9 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
                if (trace_kprobe_is_return(tk) != 
trace_kprobe_is_return(old_tk)) {
                        trace_probe_log_set_index(0);
                        trace_probe_log_err(0, DIFF_PROBE_TYPE);
-                       ret = -EEXIST;
-               } else {
-                       ret = append_trace_kprobe(tk, old_tk);
+                       return -EEXIST;
                }
-               goto end;
+               return append_trace_kprobe(tk, old_tk);
        }
 
        /* Register new event */
@@ -657,7 +655,7 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
                        trace_probe_log_err(0, EVENT_EXIST);
                } else
                        pr_warn("Failed to register probe event(%d)\n", ret);
-               goto end;
+               return ret;
        }
 
        /* Register k*probe */
@@ -672,8 +670,6 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
        else
                dyn_event_add(&tk->devent, trace_probe_event_call(&tk->tp));
 
-end:
-       mutex_unlock(&event_mutex);
        return ret;
 }
 
@@ -706,7 +702,7 @@ static int trace_kprobe_module_callback(struct 
notifier_block *nb,
                return NOTIFY_DONE;
 
        /* Update probes on coming module */
-       mutex_lock(&event_mutex);
+       guard(mutex)(&event_mutex);
        for_each_trace_kprobe(tk, pos) {
                if (trace_kprobe_within_module(tk, mod)) {
                        /* Don't need to check busy - this should have gone. */
@@ -718,7 +714,6 @@ static int trace_kprobe_module_callback(struct 
notifier_block *nb,
                                        module_name(mod), ret);
                }
        }
-       mutex_unlock(&event_mutex);
 
        return NOTIFY_DONE;
 }
@@ -1968,13 +1963,12 @@ static __init void enable_boot_kprobe_events(void)
        struct trace_kprobe *tk;
        struct dyn_event *pos;
 
-       mutex_lock(&event_mutex);
+       guard(mutex)(&event_mutex);
        for_each_trace_kprobe(tk, pos) {
                list_for_each_entry(file, &tr->events, list)
                        if (file->event_call == trace_probe_event_call(&tk->tp))
                                trace_event_enable_disable(file, 1, 0);
        }
-       mutex_unlock(&event_mutex);
 }
 
 static __init void setup_boot_kprobe_events(void)