tracing/probes: Delete dead code in trace_eprobe_tp_update_arg()

[PATCH] tracing/probes: Delete dead code in trace_eprobe_tp_update_arg()

Posted by Dan Carpenter 2 years, 7 months ago

This code was recently refactored and now the "ret" variable is always
zero.  Delete the check for non-zero.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
This code was changed in 1b8b0cd754cd (tracing/probes: Move event
parameter fetching code to common parser)

 kernel/trace/trace_eprobe.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index cb0077ba2b49..b5181d690b4d 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -797,10 +797,7 @@ static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[
 		return ret;
 
 	/* Handle symbols "@" */
-	if (!ret)
-		ret = traceprobe_update_arg(&ep->tp.args[i]);
-
-	return ret;
+	return traceprobe_update_arg(&ep->tp.args[i]);
 }
 
 static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const char *argv[])
-- 
2.39.2

Re: [PATCH] tracing/probes: Delete dead code in trace_eprobe_tp_update_arg()

Posted by Masami Hiramatsu (Google) 2 years, 7 months ago

On Mon, 26 Jun 2023 16:35:06 +0300
Dan Carpenter <dan.carpenter@linaro.org> wrote:

> This code was recently refactored and now the "ret" variable is always
> zero.  Delete the check for non-zero.
> 

Good catch!

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

> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> ---
> This code was changed in 1b8b0cd754cd (tracing/probes: Move event
> parameter fetching code to common parser)

OK, this will be picked to the 6.5 fix.

Thank you!

> 
>  kernel/trace/trace_eprobe.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
> index cb0077ba2b49..b5181d690b4d 100644
> --- a/kernel/trace/trace_eprobe.c
> +++ b/kernel/trace/trace_eprobe.c
> @@ -797,10 +797,7 @@ static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[
>  		return ret;
>  
>  	/* Handle symbols "@" */
> -	if (!ret)
> -		ret = traceprobe_update_arg(&ep->tp.args[i]);
> -
> -	return ret;
> +	return traceprobe_update_arg(&ep->tp.args[i]);
>  }
>  
>  static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const char *argv[])
> -- 
> 2.39.2
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH] tracing/probes: Delete dead code in trace_eprobe_tp_update_arg()

Posted by Steven Rostedt 2 years, 7 months ago

On Sun, 2 Jul 2023 08:02:38 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:

> On Mon, 26 Jun 2023 16:35:06 +0300
> Dan Carpenter <dan.carpenter@linaro.org> wrote:
> 
> > This code was recently refactored and now the "ret" variable is always
> > zero.  Delete the check for non-zero.
> >   

Yep! The code use to be:

	if (ep->tp.args[i].code->op == FETCH_OP_TP_ARG) {
		ret = trace_eprobe_tp_arg_update(ep, i);
		if (ret)
			trace_probe_log_err(0, BAD_ATTACH_ARG);
	}

	/* Handle symbols "@" */
	if (!ret)
		ret = traceprobe_update_arg(&ep->tp.args[i]);

	return ret;
}

and is now:

        ret = traceprobe_parse_probe_arg(&ep->tp, i, argv[i], &ctx);
        if (ret)
                return ret;

        /* Handle symbols "@" */
        if (!ret)
                ret = traceprobe_update_arg(&ep->tp.args[i]);

        return ret;
}

so that last ret check is redundant.

> 
> Good catch!
> 
> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

> 
> > Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
> > ---
> > This code was changed in 1b8b0cd754cd (tracing/probes: Move event
> > parameter fetching code to common parser)  
> 
> OK, this will be picked to the 6.5 fix.

Thanks Masami and Dan,

-- Steve

> 
> Thank you!
> 
> > 
> >  kernel/trace/trace_eprobe.c | 5 +----
> >  1 file changed, 1 insertion(+), 4 deletions(-)
> > 
> > diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
> > index cb0077ba2b49..b5181d690b4d 100644
> > --- a/kernel/trace/trace_eprobe.c
> > +++ b/kernel/trace/trace_eprobe.c
> > @@ -797,10 +797,7 @@ static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[
> >  		return ret;
> >  
> >  	/* Handle symbols "@" */
> > -	if (!ret)
> > -		ret = traceprobe_update_arg(&ep->tp.args[i]);
> > -
> > -	return ret;
> > +	return traceprobe_update_arg(&ep->tp.args[i]);
> >  }
> >  
> >  static int trace_eprobe_parse_filter(struct trace_eprobe *ep, int argc, const char *argv[])
> > -- 
> > 2.39.2
> >   
> 
>