On Tue, 2009-03-24 at 13:55 +1100, Jeremy Kerr wrote: > Currently, we don't enforce any ordering for updates to the lppaca > when enabling dtl logging, so we may end up enabling logging before the > index fields have been established. > > This change adds a smp_wmb() before doing the actual enable. > > Signed-off-by: Jeremy Kerr <j...@ozlabs.org> > > --- > arch/powerpc/platforms/pseries/dtl.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/powerpc/platforms/pseries/dtl.c > b/arch/powerpc/platforms/pseries/dtl.c > index dc9b0f8..fafcaa0 100644 > --- a/arch/powerpc/platforms/pseries/dtl.c > +++ b/arch/powerpc/platforms/pseries/dtl.c > @@ -107,6 +107,10 @@ static int dtl_enable(struct dtl *dtl) > /* set our initial buffer indices */ > dtl->last_idx = lppaca[dtl->cpu].dtl_idx = 0; > > + /* ensure that our updates to the lppaca fields have occurred before > + * we actually enable the logging */ > + smp_wmb();
Wouldn't this still be a problem on a UP kernel? cheers -- Michael Ellerman OzLabs, IBM Australia Development Lab wwweb: http://michael.ellerman.id.au phone: +61 2 6212 1183 (tie line 70 21183) We do not inherit the earth from our ancestors, we borrow it from our children. - S.M.A.R.T Person
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