[PATCH v2 3/6] tracing/kprobe: Adopt guard() and scoped_guard()

Masami Hiramatsu (Google)
2024-11-29T16:48:13Z

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

Signed-off-by: Masami Hiramatsu (Google) <mhiramat@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)