Re: [PATCH tip/core/rcu 07/28] Fix mismatched variable inrcutree_trace.c

From: Paul E. McKenney
Date: Wed Jun 08 2011 - 20:04:01 EST


On Wed, Jun 08, 2011 at 07:23:29PM -0400, Mathieu Desnoyers wrote:
> * Paul E. McKenney (paulmck@xxxxxxxxxxxxxxxxxx) wrote:
> > From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> >
> > rcutree.c defines rcu_cpu_kthread_cpu as int, not unsigned int,
> > so the extern has to follow that.
>
> How comes this discrepancy was made possible in the first place ? This
> declaration should appear in a header included by both rcutree_trace.c
> and rcutree.c, which would have permitted the compiler to detect this.
>
> Maybe kernel/rcutree.h would be a good location for these ?

I vaguely recall a time where this didn't work, but will give it
another try. It would certainly be nicer if the compiler checked
for these sorts of mismatches!

Thanx, Paul

> Mathieu
>
> >
> > Cc: paulmck@xxxxxxxxxxxxxxxxxx
> > Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> > ---
> > kernel/rcutree_trace.c | 2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c
> > index 9678cc3..91c56e5 100644
> > --- a/kernel/rcutree_trace.c
> > +++ b/kernel/rcutree_trace.c
> > @@ -47,7 +47,7 @@
> > #include "rcutree.h"
> >
> > DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
> > -DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_cpu);
> > +DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu);
> > DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
> > DECLARE_PER_CPU(char, rcu_cpu_has_work);
> >
> > --
> > 1.7.3.2
> >
>
> --
> Mathieu Desnoyers
> Operating System Efficiency R&D Consultant
> EfficiOS Inc.
> http://www.efficios.com
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