On Fri, Jul 12, 2019 at 01:01:42PM +0200, Peter Zijlstra wrote: > On Thu, Jul 11, 2019 at 07:43:56PM -0400, Joel Fernandes (Google) wrote: > > This patch adds support for checking RCU reader sections in list > > traversal macros. Optionally, if the list macro is called under SRCU or > > other lock/mutex protection, then appropriate lockdep expressions can be > > passed to make the checks pass. > > > > Existing list_for_each_entry_rcu() invocations don't need to pass the > > optional fourth argument (cond) unless they are under some non-RCU > > protection and needs to make lockdep check pass. > > > > Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> > > --- > > include/linux/rculist.h | 29 ++++++++++++++++++++++++----- > > include/linux/rcupdate.h | 7 +++++++ > > kernel/rcu/Kconfig.debug | 11 +++++++++++ > > kernel/rcu/update.c | 26 ++++++++++++++++++++++++++ > > 4 files changed, 68 insertions(+), 5 deletions(-) > > > > diff --git a/include/linux/rculist.h b/include/linux/rculist.h > > index e91ec9ddcd30..78c15ec6b2c9 100644 > > --- a/include/linux/rculist.h > > +++ b/include/linux/rculist.h > > @@ -40,6 +40,23 @@ static inline void INIT_LIST_HEAD_RCU(struct list_head *list) > > */ > > #define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next))) > > > > +/* > > + * Check during list traversal that we are within an RCU reader > > + */ > > + > > +#define SIXTH_ARG(a1, a2, a3, a4, a5, a6, ...) a6 > > +#define COUNT_VARGS(...) SIXTH_ARG(dummy, ## __VA_ARGS__, 4, 3, 2, 1, 0) > > You don't seem to actually use it in this patch; also linux/kernel.h has > COUNT_ARGS(). Yes, I replied after sending patches that I fixed this. I will remove them. thanks, - Joel
