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| author |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-04-18 14:14:42 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-05-15 10:29:41 -0700 |
| commit | 0ae94e00ce40e4447080ab7675220f725c690330 (patch) | |
| tree | d5c003296ddde1203898a0cb56665c5a2abeb49e /kernel/rcu | |
| parent | rcu: Avoid losing ->need_future_gp[] values due to GP start/end races (diff) | |
| download | linux-dev-0ae94e00ce40e4447080ab7675220f725c690330.tar.xz linux-dev-0ae94e00ce40e4447080ab7675220f725c690330.zip | |
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>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.c | 2 | ||||
| -rw-r--r-- | 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; \ }) |