From: Matt Fleming <matt@codeblueprint.co.uk>
Date: Sun, 26 Jan 2020 21:19:45 +0000
Subject: [PATCH] mm/memcontrol: Move misplaced local_unlock_irqrestore()

The comment about local_lock_irqsave() mentions just the counters and
css_put_many()'s callback just invokes a worker so it is safe to move the
unlock function after memcg_check_events() so css_put_many() can be invoked
without the lock acquired.

Cc: Daniel Wagner <wagi@monom.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
[bigeasy: rewrote the patch description]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 mm/memcontrol.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -7017,10 +7017,10 @@ void mem_cgroup_swapout(struct page *pag
 	mem_cgroup_charge_statistics(memcg, page, PageTransHuge(page),
 				     -nr_entries);
 	memcg_check_events(memcg, page);
+	local_unlock_irqrestore(event_lock, flags);
 
 	if (!mem_cgroup_is_root(memcg))
 		css_put_many(&memcg->css, nr_entries);
-	local_unlock_irqrestore(event_lock, flags);
 }
 
 /**