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Date:   Fri, 7 Dec 2018 11:22:29 +0900
From:   Masami Hiramatsu <mhiramat@kernel.org>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
        Tom Zanussi <tom.zanussi@linux.intel.com>,
        Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Subject: Re: [PATCH v2 10/12] tracing: Remove orphaned
 trace_add/remove_event_call functions
Message-Id: <20181207112229.ee3f875b46d54d99fbd47c9f@kernel.org>
In-Reply-To: <20181204135120.02361a89@vmware.local.home>
References: <154140838606.17322.15294184388075458777.stgit@devbox>
        <154140866955.17322.2081425494660638846.stgit@devbox>
        <20181204135120.02361a89@vmware.local.home>
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On Tue, 4 Dec 2018 13:51:20 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Mon,  5 Nov 2018 18:04:29 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > Remove trace_add_event_call() and trace_remove_event_call()
> > functions since those are not used anymore.
> > 
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> 
> 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"

Agreed.

> 
> I added this patch in its place:

That looks good to me too. I thought to add similar patch, but just waited
for the comment.

Acked-by: Masami Hiramatsu <mhiramat@kernel.org>

Thank you!

> 
> -- Steve
> 
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 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@goodmis.org>
> ---
>  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
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>