Re: [PATCH 4/5] tracing/kprobes: Do not open code event reserve logic

[Masami Hiramatsu <mhiramat@kernel.org>]

On Mon, 29 Nov 2021 21:39:49 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> 
> As kprobe events use trace_event_buffer_commit() to commit the event to
> the ftrace ring buffer, for consistency, it should use
> trace_event_buffer_reserve() to allocate it, as the two functions are
> related.

OK, I got the rule.

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

BTW, what should be used for trace_event_buffer_lock_reserve() as a pair call?

Thanks!

> Cc: Masami Hiramatsu <mhiramat@kernel.org>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
>  kernel/trace/trace_kprobe.c | 25 +++++++------------------
>  1 file changed, 7 insertions(+), 18 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 33272a7b6912..d10c01948e68 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1383,17 +1383,11 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,
>  	if (trace_trigger_soft_disabled(trace_file))
>  		return;
>  
> -	fbuffer.trace_ctx = tracing_gen_ctx();
> -	fbuffer.trace_file = trace_file;
> -
>  	dsize = __get_data_size(&tk->tp, regs);
>  
> -	fbuffer.event =
> -		trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
> -					call->event.type,
> -					sizeof(*entry) + tk->tp.size + dsize,
> -					fbuffer.trace_ctx);
> -	if (!fbuffer.event)
> +	entry = trace_event_buffer_reserve(&fbuffer, trace_file,
> +					   sizeof(*entry) + tk->tp.size + dsize);
> +	if (!entry)
>  		return;
>  
>  	fbuffer.regs = regs;
> @@ -1430,16 +1424,11 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,
>  	if (trace_trigger_soft_disabled(trace_file))
>  		return;
>  
> -	fbuffer.trace_ctx = tracing_gen_ctx();
> -	fbuffer.trace_file = trace_file;
> -
>  	dsize = __get_data_size(&tk->tp, regs);
> -	fbuffer.event =
> -		trace_event_buffer_lock_reserve(&fbuffer.buffer, trace_file,
> -					call->event.type,
> -					sizeof(*entry) + tk->tp.size + dsize,
> -					fbuffer.trace_ctx);
> -	if (!fbuffer.event)
> +
> +	entry = trace_event_buffer_reserve(&fbuffer, trace_file,
> +					   sizeof(*entry) + tk->tp.size + dsize);
> +	if (!entry)
>  		return;
>  
>  	fbuffer.regs = regs;
> -- 
> 2.33.0


-- 
Masami Hiramatsu <mhiramat@kernel.org>