[PATCH] zcache: Use WARN_ON_SMP in ASSERT_SPINLOCK

Jörg Sommer joerg at alea.gnuu.de
Mon Mar 12 20:01:13 UTC 2012


Greg Kroah-Hartman hat am Sun 11. Mar, 19:50 (-0700) geschrieben:
> On Sun, Mar 11, 2012 at 10:00:54PM +0100, Jörg Sommer wrote:
> > As the description of WARN_ON_SMP in bug.h says, one can not use
> > spin_is_locked() in assertions for non‐SMP configurations, because it
> > always returns the lock is not held. Otherwise a warning is thrown
> > everytime on a uniprocessor system.
> > ---
> >  drivers/staging/zcache/tmem.h |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> > 
> > diff --git a/drivers/staging/zcache/tmem.h b/drivers/staging/zcache/tmem.h
> > index ed147c4..b543694 100644
> > --- a/drivers/staging/zcache/tmem.h
> > +++ b/drivers/staging/zcache/tmem.h
> > @@ -47,7 +47,7 @@
> >  #define ASSERT_INVERTED_SENTINEL(_x, _y) do { } while (0)
> >  #endif
> >  
> > -#define ASSERT_SPINLOCK(_l)	WARN_ON(!spin_is_locked(_l))
> > +#define ASSERT_SPINLOCK(_l)	WARN_ON_SMP(!spin_is_locked(_l))
> 
> Why do we even have asserts in this code in the first place?  Shouldn't
> they all be removed by now?

I don't know, why the asserts are there. But if the asserts get removed,
the sentinel zones can be removed, too, because noone checks them. This
would be a big interference. If the code is stable enough, it can be
cleaned up. But I can't say anything about it. I couldn't use zcache
until now, because the kernel flooded the log with warnings.

Regards, Jörg.
-- 
Der Klügere gibt so lange nach bis er der Dumme ist.
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