Re: [PATCH] rculist: fix borked __list_for_each_rcu() macro

From: Paul E. McKenney
Date: Thu Dec 16 2010 - 10:51:26 EST


On Thu, Dec 16, 2010 at 07:02:36AM +0100, Mariusz Kozlowski wrote:
> On Wed, Dec 15, 2010 at 03:20:05PM -0800, Paul E. McKenney wrote:
> > On Wed, Dec 15, 2010 at 11:11:12PM +0100, Mariusz Kozlowski wrote:
> > > This restores parentheses blance.
> >
> > Good catch, queued!!!
> >
> > This does not actually appear to be in use anywhere in the kernel any
> > more, so I queued this for 2.6.38 rather than in the 2.6.37 urgent queue.
> > So, just out of curiosity, how did you find this one?
>
> Some years ago I wrote a dumb script that walks trees of () and {}.
> It catches unbalanced trees. It's dumb enough to fail with #ifdef etc,
> but most of the time it does its job. It reaches unreachable code
> and unused one too.

Very cool, and thank you!

Thanx, Paul

> > Hmmm... Maybe we should just delete __list_for_each_rcu. ;-)
> >
> > Thanx, Paul
> >
> > > Signed-off-by: Mariusz Kozlowski <mk@xxxxxxxxxxxx>
> > > ---
> > > include/linux/rculist.h | 2 +-
> > > 1 files changed, 1 insertions(+), 1 deletions(-)
> > >
> > > diff --git a/include/linux/rculist.h b/include/linux/rculist.h
> > > index f31ef61..70d3ba5 100644
> > > --- a/include/linux/rculist.h
> > > +++ b/include/linux/rculist.h
> > > @@ -244,7 +244,7 @@ static inline void list_splice_init_rcu(struct list_head *list,
> > > #define __list_for_each_rcu(pos, head) \
> > > for (pos = rcu_dereference_raw(list_next_rcu(head)); \
> > > pos != (head); \
> > > - pos = rcu_dereference_raw(list_next_rcu((pos)))
> > > + pos = rcu_dereference_raw(list_next_rcu(pos)))
> > >
> > > /**
> > > * list_for_each_entry_rcu - iterate over rcu list of given type
> > > --
> > > 1.7.0.4
> > >
>
> --
> Mariusz Kozlowski
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