Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU changes from Ingo Molnar:
 "The main changes in this cycle were:

   - Improvements to expedited grace periods (Paul E McKenney)

   - Performance improvements to and locktorture tests for percpu-rwsem
     (Oleg Nesterov, Paul E McKenney)

   - Torture-test changes (Paul E McKenney, Davidlohr Bueso)

   - Documentation updates (Paul E McKenney)

   - Miscellaneous fixes (Paul E McKenney, Boqun Feng, Oleg Nesterov,
     Patrick Marlier)"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (54 commits)
  fs/writeback, rcu: Don't use list_entry_rcu() for pointer offsetting in bdi_split_work_to_wbs()
  rcu: Better hotplug handling for synchronize_sched_expedited()
  rcu: Enable stall warnings for synchronize_rcu_expedited()
  rcu: Add tasks to expedited stall-warning messages
  rcu: Add online/offline info to expedited stall warning message
  rcu: Consolidate expedited CPU selection
  rcu: Prepare for consolidating expedited CPU selection
  cpu: Remove try_get_online_cpus()
  rcu: Stop excluding CPU hotplug in synchronize_sched_expedited()
  rcu: Stop silencing lockdep false positive for expedited grace periods
  rcu: Switch synchronize_sched_expedited() to IPI
  locktorture: Fix module unwind when bad torture_type specified
  torture: Forgive non-plural arguments
  rcutorture: Fix unused-function warning for torturing_tasks()
  rcutorture: Fix module unwind when bad torture_type specified
  rcu_sync: Cleanup the CONFIG_PROVE_RCU checks
  locking/percpu-rwsem: Clean up the lockdep annotations in percpu_down_read()
  locking/percpu-rwsem: Fix the comments outdated by rcu_sync
  locking/percpu-rwsem: Make use of the rcu_sync infrastructure
  locking/percpu-rwsem: Make percpu_free_rwsem() after kzalloc() safe
  ...

1 files changed, 3 insertions, 2 deletions

diff --git a/include/linux/list.h b/include/linux/list.h
index 3e3e64a61002..993395a2e55c 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -87,7 +87,7 @@ static inline void list_add_tail(struct list_head *new, struct list_head *head)
 static inline void __list_del(struct list_head * prev, struct list_head * next)
 {
 	next->prev = prev;
-	prev->next = next;
+	WRITE_ONCE(prev->next, next);
 }
 
 /**
@@ -615,7 +615,8 @@ static inline void __hlist_del(struct hlist_node *n)
 {
 	struct hlist_node *next = n->next;
 	struct hlist_node **pprev = n->pprev;
-	*pprev = next;
+
+	WRITE_ONCE(*pprev, next);
 	if (next)
 		next->pprev = pprev;
 }