Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH tip/core/rcu 07/21] rcu: Make rcu_future_needs_gp() check all ->need_future_gps[] elements | Date | Sun, 22 Apr 2018 20:03:30 -0700 |
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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> --- kernel/rcu/tree.c | 2 +- kernel/rcu/tree.h | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index afc5e32f0da4..b05ab6379562 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -720,7 +720,7 @@ static int rcu_future_needs_gp(struct rcu_state *rsp) struct rcu_node *rnp = rcu_get_root(rsp); lockdep_assert_irqs_disabled(); - return READ_ONCE(need_future_gp_element(rnp, rnp->completed)); + return need_any_future_gp(rnp); } /* diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 952cd0c223fe..123c30eac8b5 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; \ }) -- 2.5.2
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