Merge wireless into wireless-next

Resolve several conflicts, mostly between changes/fixes in
wireless and the locking rework in wireless-next. One of
the conflicts actually shows a bug in wireless that we'll
want to fix separately.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>

1 files changed, 10 insertions, 6 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 1449cb69a0e0..cb1caefa8bd0 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -632,7 +632,7 @@ void __rcu_irq_enter_check_tick(void)
 	// prevents self-deadlock.  So we can safely recheck under the lock.
 	// Note that the nohz_full state currently cannot change.
 	raw_spin_lock_rcu_node(rdp->mynode);
-	if (rdp->rcu_urgent_qs && !rdp->rcu_forced_tick) {
+	if (READ_ONCE(rdp->rcu_urgent_qs) && !rdp->rcu_forced_tick) {
 		// A nohz_full CPU is in the kernel and RCU needs a
 		// quiescent state.  Turn on the tick!
 		WRITE_ONCE(rdp->rcu_forced_tick, true);
@@ -677,12 +677,16 @@ static void rcu_disable_urgency_upon_qs(struct rcu_data *rdp)
 }
 
 /**
- * rcu_is_watching - see if RCU thinks that the current CPU is not idle
+ * rcu_is_watching - RCU read-side critical sections permitted on current CPU?
  *
- * Return true if RCU is watching the running CPU, which means that this
- * CPU can safely enter RCU read-side critical sections.  In other words,
- * if the current CPU is not in its idle loop or is in an interrupt or
- * NMI handler, return true.
+ * Return @true if RCU is watching the running CPU and @false otherwise.
+ * An @true return means that this CPU can safely enter RCU read-side
+ * critical sections.
+ *
+ * Although calls to rcu_is_watching() from most parts of the kernel
+ * will return @true, there are important exceptions.  For example, if the
+ * current CPU is deep within its idle loop, in kernel entry/exit code,
+ * or offline, rcu_is_watching() will return @false.
  *
  * Make notrace because it can be called by the internal functions of
  * ftrace, and making this notrace removes unnecessary recursion calls.