[PATCH] rcu: remove lock acquirement when very eary boot

[Lai Jiangshan]

cleanup: remove lock acquirement when very eary boot

Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com>
---
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 112edb5..e6014e1 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1646,13 +1646,10 @@ EXPORT_SYMBOL_GPL(rcu_barrier_sched);
static void __init
rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
{
- unsigned long flags;
int i;
struct rcu_data *rdp = rsp->rda[cpu];
- struct rcu_node *rnp = rcu_get_root(rsp);

/* Set up local state, ensuring consistent view of global state. */
- raw_spin_lock_irqsave(&rnp->lock, flags);
rdp->grpmask = 1UL << (cpu - rdp->mynode->grplo);
rdp->nxtlist = NULL;
for (i = 0; i < RCU_NEXT_SIZE; i++)
@@ -1662,7 +1659,6 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
rdp->dynticks = &per_cpu(rcu_dynticks, cpu);
#endif /* #ifdef CONFIG_NO_HZ */
rdp->cpu = cpu;
- raw_spin_unlock_irqrestore(&rnp->lock, flags);
}

/*

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[Paul E. McKenney]

On Sun, Mar 28, 2010 at 11:14:13AM +0800, Lai Jiangshan wrote:
>
> cleanup: remove lock acquirement when very eary boot

This is indeed a safe change, however, I am keeping this lock acquisition
and release for documentation purposes. Call me paranoid, but...

Thanx, Paul