On Wed, Nov 29, 2017 at 11:51:51AM +1100, Stephen Rothwell wrote:
> Hi Paul,
>
> Commit
>
> d7e182c9c324 ("rcu: Remove unnecessary spinlock in
> rcu_boot_init_percpu_data()")
>
> is missing a Signed-off-by from its author.
Good catch, Stephen!
Lihao, would you please get me you Signed-off-by? The patch is below.
Thanx, Paul
------------------------------------------------------------------------
commit d7e182c9c32480c1f579dd888ac50e88bfb39596
Author: Liang Lihao <liangli...@huawei.com>
Date: Wed Nov 22 19:00:55 2017 +0000
rcu: Remove unnecessary spinlock in rcu_boot_init_percpu_data()
Since rcu_boot_init_percpu_data() is only called at boot time,
there is no data race and spinlock is not needed.
Signed-off-by: Paul E. McKenney <paul...@linux.vnet.ibm.com>
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 69722817d6d6..0abe1db53d70 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3636,12 +3636,9 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf)
static void __init
rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
{
- unsigned long flags;
struct rcu_data *rdp = per_cpu_ptr(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_rcu_node(rnp, flags);
rdp->grpmask = leaf_node_cpu_bit(rdp->mynode, cpu);
rdp->dynticks = &per_cpu(rcu_dynticks, cpu);
WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != 1);
@@ -3649,7 +3646,6 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
rdp->cpu = cpu;
rdp->rsp = rsp;
rcu_boot_init_nocb_percpu_data(rdp);
- raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
/*
