rcu: Make rcu_future_needs_gp() check all ->need_future_gps[] elements
Currently, the rcu_future_needs_gp() function checks only the current
element of the ->need_future_gps[] array, which might miss elements that
were offset from the expected element, for example, due to races with
the start or the end of a grace period. This commit therefore makes
rcu_future_needs_gp() use the need_any_future_gp() macro to check all
of the elements of this array.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 952cd0c..123c30e 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -169,7 +169,8 @@ struct rcu_node {
bool __nonzero = false; \
\
for (__i = 0; __i < ARRAY_SIZE((rnp)->need_future_gp); __i++) \
- __nonzero = __nonzero || (rnp)->need_future_gp[__i]; \
+ __nonzero = __nonzero || \
+ READ_ONCE((rnp)->need_future_gp[__i]); \
__nonzero; \
})