tracing/eprobe: Iterate trace_eprobe directly

Refer to the description in [1], we can skip "container_of()" following
"list_for_each_entry()" by using "list_for_each_entry()" with
"struct trace_eprobe" and "tp.list".

Also, this patch defines "for_each_trace_eprobe_tp" to simplify the code
of the same logic.

[1] https://lore.kernel.org/all/CAHk-=wjakjw6-rDzDDBsuMoDCqd+9ogifR_EE1F0K-jYek1CdA@mail.gmail.com/

Link: https://lore.kernel.org/all/20230822022433.262478-1-nashuiliang@gmail.com/
Signed-off-by: Chuang Wang <nashuiliang@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index a0a704b..6a024b5 100644 (file)
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -41,6 +41,10 @@ struct eprobe_data {
        struct trace_eprobe     *ep;
 };
 
+
+#define for_each_trace_eprobe_tp(ep, _tp) \
+       list_for_each_entry(ep, trace_probe_probe_list(_tp), tp.list)
+
 static int __trace_eprobe_create(int argc, const char *argv[]);
 
 static void trace_event_probe_cleanup(struct trace_eprobe *ep)
@@ -640,7 +644,7 @@ static int disable_eprobe(struct trace_eprobe *ep,
 static int enable_trace_eprobe(struct trace_event_call *call,
                               struct trace_event_file *file)
 {
-       struct trace_probe *pos, *tp;
+       struct trace_probe *tp;
        struct trace_eprobe *ep;
        bool enabled;
        int ret = 0;
@@ -662,8 +666,7 @@ static int enable_trace_eprobe(struct trace_event_call *call,
        if (enabled)
                return 0;
 
-       list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
-               ep = container_of(pos, struct trace_eprobe, tp);
+       for_each_trace_eprobe_tp(ep, tp) {
                ret = enable_eprobe(ep, file);
                if (ret)
                        break;
@@ -680,8 +683,7 @@ static int enable_trace_eprobe(struct trace_event_call *call,
                         */
                        WARN_ON_ONCE(ret != -ENOMEM);
 
-                       list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
-                               ep = container_of(pos, struct trace_eprobe, tp);
+                       for_each_trace_eprobe_tp(ep, tp) {
                                disable_eprobe(ep, file->tr);
                                if (!--cnt)
                                        break;
@@ -699,7 +701,7 @@ static int enable_trace_eprobe(struct trace_event_call *call,
 static int disable_trace_eprobe(struct trace_event_call *call,
                                struct trace_event_file *file)
 {
-       struct trace_probe *pos, *tp;
+       struct trace_probe *tp;
        struct trace_eprobe *ep;
 
        tp = trace_probe_primary_from_call(call);
@@ -716,10 +718,8 @@ static int disable_trace_eprobe(struct trace_event_call *call,
                trace_probe_clear_flag(tp, TP_FLAG_PROFILE);
 
        if (!trace_probe_is_enabled(tp)) {
-               list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
-                       ep = container_of(pos, struct trace_eprobe, tp);
+               for_each_trace_eprobe_tp(ep, tp)
                        disable_eprobe(ep, file->tr);
-               }
        }
 
  out: