Re: [PATCH v2 10/12] tracing: Remove orphaned trace_add/remove_event_call functions

From: Steven Rostedt
Date: Tue Dec 04 2018 - 13:51:26 EST


On Mon, 5 Nov 2018 18:04:29 +0900
Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:

> Remove trace_add_event_call() and trace_remove_event_call()
> functions since those are not used anymore.
>
> Signed-off-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>

Hi Masami,

I've applied the series locally (need to test it) except for this
patch. Honestly, I hate the "_nolock" name, and it makes no sense when

1) they still grab locks
2) there's no version without "_nolock"

I added this patch in its place:

-- Steve

From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>
Date: Tue, 4 Dec 2018 13:35:45 -0500
Subject: [PATCH] tracing: Consolidate trace_add/remove_event_call back to the
nolock functions

The trace_add/remove_event_call_nolock() functions were added to allow
the tace_add/remove_event_call() code be called when the event_mutex
lock was already taken. Now that all callers are done within the
event_mutex, there's no reason to have two different interfaces.

Remove the current wrapper trace_add/remove_event_call()s and rename the
_nolock versions back to the original names.

Link: http://lkml.kernel.org/r/154140866955.17322.2081425494660638846.stgit@devbox

Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
include/linux/trace_events.h | 2 --
kernel/trace/trace_events.c | 30 ++++--------------------------
kernel/trace/trace_events_hist.c | 6 +++---
kernel/trace/trace_kprobe.c | 4 ++--
kernel/trace/trace_uprobe.c | 4 ++--
5 files changed, 11 insertions(+), 35 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 3aa05593a53f..4130a5497d40 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -529,8 +529,6 @@ extern int trace_event_raw_init(struct trace_event_call *call);
extern int trace_define_field(struct trace_event_call *call, const char *type,
const char *name, int offset, int size,
int is_signed, int filter_type);
-extern int trace_add_event_call_nolock(struct trace_event_call *call);
-extern int trace_remove_event_call_nolock(struct trace_event_call *call);
extern int trace_add_event_call(struct trace_event_call *call);
extern int trace_remove_event_call(struct trace_event_call *call);
extern int trace_event_get_offsets(struct trace_event_call *call);
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a3b157f689ee..bd0162c0467c 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2305,7 +2305,8 @@ __trace_early_add_new_event(struct trace_event_call *call,
struct ftrace_module_file_ops;
static void __add_event_to_tracers(struct trace_event_call *call);

-int trace_add_event_call_nolock(struct trace_event_call *call)
+/* Add an additional event_call dynamically */
+int trace_add_event_call(struct trace_event_call *call)
{
int ret;
lockdep_assert_held(&event_mutex);
@@ -2320,17 +2321,6 @@ int trace_add_event_call_nolock(struct trace_event_call *call)
return ret;
}

-/* Add an additional event_call dynamically */
-int trace_add_event_call(struct trace_event_call *call)
-{
- int ret;
-
- mutex_lock(&event_mutex);
- ret = trace_add_event_call_nolock(call);
- mutex_unlock(&event_mutex);
- return ret;
-}
-
/*
* Must be called under locking of trace_types_lock, event_mutex and
* trace_event_sem.
@@ -2376,8 +2366,8 @@ static int probe_remove_event_call(struct trace_event_call *call)
return 0;
}

-/* no event_mutex version */
-int trace_remove_event_call_nolock(struct trace_event_call *call)
+/* Remove an event_call */
+int trace_remove_event_call(struct trace_event_call *call)
{
int ret;

@@ -2392,18 +2382,6 @@ int trace_remove_event_call_nolock(struct trace_event_call *call)
return ret;
}

-/* Remove an event_call */
-int trace_remove_event_call(struct trace_event_call *call)
-{
- int ret;
-
- mutex_lock(&event_mutex);
- ret = trace_remove_event_call_nolock(call);
- mutex_unlock(&event_mutex);
-
- return ret;
-}
-
#define for_each_event(event, start, end) \
for (event = start; \
(unsigned long)event < (unsigned long)end; \
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 21e4954375a1..82e72c48a5a9 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -960,7 +960,7 @@ static int register_synth_event(struct synth_event *event)
call->data = event;
call->tp = event->tp;

- ret = trace_add_event_call_nolock(call);
+ ret = trace_add_event_call(call);
if (ret) {
pr_warn("Failed to register synthetic event: %s\n",
trace_event_name(call));
@@ -969,7 +969,7 @@ static int register_synth_event(struct synth_event *event)

ret = set_synth_event_print_fmt(call);
if (ret < 0) {
- trace_remove_event_call_nolock(call);
+ trace_remove_event_call(call);
goto err;
}
out:
@@ -984,7 +984,7 @@ static int unregister_synth_event(struct synth_event *event)
struct trace_event_call *call = &event->call;
int ret;

- ret = trace_remove_event_call_nolock(call);
+ ret = trace_remove_event_call(call);

return ret;
}
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index bdf8c2ad5152..0e0f7b8024fb 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1353,7 +1353,7 @@ static int register_kprobe_event(struct trace_kprobe *tk)
kfree(call->print_fmt);
return -ENODEV;
}
- ret = trace_add_event_call_nolock(call);
+ ret = trace_add_event_call(call);
if (ret) {
pr_info("Failed to register kprobe event: %s\n",
trace_event_name(call));
@@ -1368,7 +1368,7 @@ static int unregister_kprobe_event(struct trace_kprobe *tk)
int ret;

/* tp->event is unregistered in trace_remove_event_call() */
- ret = trace_remove_event_call_nolock(&tk->tp.call);
+ ret = trace_remove_event_call(&tk->tp.call);
if (!ret)
kfree(tk->tp.call.print_fmt);
return ret;
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 4a7b21c891f3..e335576b9411 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -1320,7 +1320,7 @@ static int register_uprobe_event(struct trace_uprobe *tu)
return -ENODEV;
}

- ret = trace_add_event_call_nolock(call);
+ ret = trace_add_event_call(call);

if (ret) {
pr_info("Failed to register uprobe event: %s\n",
@@ -1337,7 +1337,7 @@ static int unregister_uprobe_event(struct trace_uprobe *tu)
int ret;

/* tu->event is unregistered in trace_remove_event_call() */
- ret = trace_remove_event_call_nolock(&tu->tp.call);
+ ret = trace_remove_event_call(&tu->tp.call);
if (ret)
return ret;
kfree(tu->tp.call.print_fmt);
--
2.19.2