rcu: Avoid misordering in __call_rcu_nocb_enqueue()

The NOCB leader wakeup ordering depends on the store to the header
happening before the check for the leader already being awake.  However,
because atomic_long_add() does not return a value, it does not provide
ordering guarantees, the incorrect comment in wake_nocb_leader()
notwithstanding.  This commit therefore adds a smp_mb__after_atomic()
after the final atomic_long_add() to provide the needed ordering
guarantee.

Reported-by: Amit Shah <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Tested-by: Paul Gortmaker <[email protected]>

0 files changed, 0 insertions, 0 deletions