[PATCH] mm/memcontrol: remove the unnecessary rcu_read_[un]lock

[Hui Su]

the rcu_read_lock and rcu_read_unlock is unnecessary in:
        lock_page_lruvec()
        lock_page_lruvec_irq()
        lock_page_lruvec_irqsave()

Signed-off-by: Hui Su <sh_...@163.com>
---
 mm/memcontrol.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e3c7ca7dc174..a19f820e8a3f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1396,10 +1396,8 @@ struct lruvec *lock_page_lruvec(struct page *page)
        struct lruvec *lruvec;
        struct pglist_data *pgdat = page_pgdat(page);
 
-       rcu_read_lock();
        lruvec = mem_cgroup_page_lruvec(page, pgdat);
        spin_lock(&lruvec->lru_lock);
-       rcu_read_unlock();
 
        lruvec_memcg_debug(lruvec, page);
 
@@ -1411,10 +1409,8 @@ struct lruvec *lock_page_lruvec_irq(struct page *page)
        struct lruvec *lruvec;
        struct pglist_data *pgdat = page_pgdat(page);
 
-       rcu_read_lock();
        lruvec = mem_cgroup_page_lruvec(page, pgdat);
        spin_lock_irq(&lruvec->lru_lock);
-       rcu_read_unlock();
 
        lruvec_memcg_debug(lruvec, page);
 
@@ -1426,10 +1422,8 @@ struct lruvec *lock_page_lruvec_irqsave(struct page 
*page, unsigned long *flags)
        struct lruvec *lruvec;
        struct pglist_data *pgdat = page_pgdat(page);
 
-       rcu_read_lock();
        lruvec = mem_cgroup_page_lruvec(page, pgdat);
        spin_lock_irqsave(&lruvec->lru_lock, *flags);
-       rcu_read_unlock();
 
        lruvec_memcg_debug(lruvec, page);
 
-- 
2.29.2