Re: [PATCH] : eliminate code duplication in kernel/tracepoint.c

From: Ingo Molnar
Date: Tue Aug 25 2009 - 02:39:18 EST



* Li Zefan <lizf@xxxxxxxxxxxxxx> wrote:

> 11:57, Anirban Sinha wrote:
> > OK, here's the modified patch:
> >
> >>From 52cea59801ac5b772c49ae995f4df1940a0d88fa Mon Sep 17 00:00:00 2001
> > From: Anirban Sinha <asinha@xxxxxxxxxxxxxxxxx>
> > Date: Mon, 24 Aug 2009 20:52:35 -0700
> > Subject: cleanup: eliminate code duplication in kernel/tracepoint.c
> >
> >
> > Signed-off-by: Anirban Sinha <asinha@xxxxxxxxxxxxxxxxx>
> > ---
> > kernel/tracepoint.c | 4 ----
> > 1 files changed, 0 insertions(+), 4 deletions(-)
> >
> > diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
> > index 1ef5d3a..35eed9c 100644
> > --- a/kernel/tracepoint.c
> > +++ b/kernel/tracepoint.c
> > @@ -554,13 +554,9 @@ int tracepoint_module_notify(struct notifier_block
> > *self,
> >
> > switch (val) {
> > case MODULE_STATE_COMING:
> > - tracepoint_update_probe_range(mod->tracepoints,
> > - mod->tracepoints + mod->num_tracepoints);
> > - break;
> > case MODULE_STATE_GOING:
> > tracepoint_update_probe_range(mod->tracepoints,
> > mod->tracepoints + mod->num_tracepoints);
> > - break;
>
> I still think it's better not to remove this break. every "case"
> should have a break or a return, expect for the falling throught
> cases.

Correct. That might seem like a superfluous statement, but when we
add new cases it stays robust while with the missing break one can
create an unintended fall-through codepath.

Ingo
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