On Tue, Jan 18, 2011 at 01:08:45PM +0200, Michael S. Tsirkin wrote: > When built with rcu checks enabled, vhost triggers > bogus warnings as vhost features are read without > dev->mutex sometimes. > Fixing it properly is not trivial as vhost.h does not > know which lockdep classes it will be used under. > Disable the warning by stubbing out the check for now. > > Signed-off-by: Michael S. Tsirkin <m...@redhat.com> > --- > drivers/vhost/vhost.h | 4 +--- > 1 files changed, 1 insertions(+), 3 deletions(-) > > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h > index 2af44b7..2d03a31 100644 > --- a/drivers/vhost/vhost.h > +++ b/drivers/vhost/vhost.h > @@ -173,9 +173,7 @@ static inline int vhost_has_feature(struct vhost_dev > *dev, int bit) > { > unsigned acked_features; > > - acked_features = > - rcu_dereference_index_check(dev->acked_features, > - lockdep_is_held(&dev->mutex)); > + acked_features = rcu_dereference_index_check(dev->acked_features, 1);
Ouch!!! Could you please at least add a comment? Alternatively, pass in the lock that is held and check for that? Given that this is a static inline, the compiler should be able to optimize the argument away when !PROVE_RCU, correct? Thanx, Paul > return acked_features & (1 << bit); > } > > -- > 1.7.3.2.91.g446ac > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html