On Tue, Sep 07, 2010 at 10:00:58PM +0200, Arnd Bergmann wrote: > On Tuesday 07 September 2010 21:21:55 Kulikov Vasiliy wrote: > > #define __rcu_dereference_check(p, c, space) \ > > ({ \ > > typeof(*p) *_________p1 = (typeof(*p)*__force )ACCESS_ONCE(p); \ > > ^ > > rcu_lockdep_assert(c); \ > > (void) (((typeof (*p) space *)p) == p); \ > > ^ ^ > > smp_read_barrier_depends(); \ > > ((typeof(*p) __force __kernel *)(_________p1)); \ > > }) > > > > If I understand this, it is evaluated three times, right? > > Yes, that looks like my own fault, I added that :( > > This patch seems to fix it, but I need to think about it some more > to make sure it still does everything we need. Let me know when you are satisfied with it, and then I will pick it up. Thanx, Paul > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > > diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h > index 89414d6..743bc3f 100644 > --- a/include/linux/rcupdate.h > +++ b/include/linux/rcupdate.h > @@ -313,21 +313,21 @@ extern int rcu_my_thread_group_empty(void); > #define __rcu_access_pointer(p, space) \ > ({ \ > typeof(*p) *_________p1 = (typeof(*p)*__force )ACCESS_ONCE(p); \ > - (void) (((typeof (*p) space *)p) == p); \ > + (void) (((typeof (*p) space *)NULL) == (typeof(p))NULL); \ > ((typeof(*p) __force __kernel *)(_________p1)); \ > }) > #define __rcu_dereference_check(p, c, space) \ > ({ \ > typeof(*p) *_________p1 = (typeof(*p)*__force )ACCESS_ONCE(p); \ > rcu_lockdep_assert(c); \ > - (void) (((typeof (*p) space *)p) == p); \ > + (void) (((typeof (*p) space *)NULL) == (typeof(p))NULL); \ > smp_read_barrier_depends(); \ > ((typeof(*p) __force __kernel *)(_________p1)); \ > }) > #define __rcu_dereference_protected(p, c, space) \ > ({ \ > rcu_lockdep_assert(c); \ > - (void) (((typeof (*p) space *)p) == p); \ > + (void) (((typeof (*p) space *)NULL) == (typeof(p))NULL); \ > ((typeof(*p) __force __kernel *)(p)); \ > }) > -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html