linux-kernel - [PATCH] kernel: sched: fair: Replace rcu_assign_pointer() with RCU_INIT

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Date:	Fri, 22 Aug 2014 17:20:55 +0300
From:	Andreea-Cristina Bernat <bernat.ada@...il.com>
To:	mingo@...hat.com, peterz@...radead.com,
	linux-kernel@...r.kernel.org
Cc:	paulmck@...ux.vnet.ibm.com
Subject: [PATCH] kernel: sched: fair: Replace rcu_assign_pointer() with
 RCU_INIT_POINTER()

The use of "rcu_assign_pointer()" is NULLing out the pointer.
According to RCU_INIT_POINTER()'s block comment:
"1.   This use of RCU_INIT_POINTER() is NULLing out the pointer"
it is better to use it instead of rcu_assign_pointer() because it has a
smaller overhead.

The following Coccinelle semantic patch was used:
@@
@@

- rcu_assign_pointer
+ RCU_INIT_POINTER
  (..., NULL)

Signed-off-by: Andreea-Cristina Bernat <bernat.ada@...il.com>
---
 kernel/sched/fair.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index fea7d33..7d4f743 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1759,7 +1759,7 @@ void task_numa_free(struct task_struct *p)
 		list_del(&p->numa_entry);
 		grp->nr_tasks--;
 		spin_unlock_irqrestore(&grp->lock, flags);
-		rcu_assign_pointer(p->numa_group, NULL);
+		RCU_INIT_POINTER(p->numa_group, NULL);
 		put_numa_group(grp);
 	}
 
-- 
1.9.1

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