rcu: Remove "cpu" argument to rcu_prepare_for_idle()

The "cpu" argument to rcu_prepare_for_idle() is always the current
CPU, so drop it.  This in turn allows two of the uses of "cpu" in
this function to be replaced with a this_cpu_ptr() and the third by
smp_processor_id(), replacing that of the call to rcu_prepare_for_idle().
Again, the anticipated cross-CPU uses of these functions has been replaced
by NO_HZ_FULL.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>

1 files changed, 5 insertions, 5 deletions

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 1797b76cb3ff..5e68ab5fe317 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1531,7 +1531,7 @@ static void rcu_cleanup_after_idle(int cpu)
  * Do the idle-entry grace-period work, which, because CONFIG_RCU_FAST_NO_HZ=n,
  * is nothing.
  */
-static void rcu_prepare_for_idle(int cpu)
+static void rcu_prepare_for_idle(void)
 {
 }
 
@@ -1666,12 +1666,12 @@ int rcu_needs_cpu(unsigned long *dj)
  *
  * The caller must have disabled interrupts.
  */
-static void rcu_prepare_for_idle(int cpu)
+static void rcu_prepare_for_idle(void)
 {
 #ifndef CONFIG_RCU_NOCB_CPU_ALL
 	bool needwake;
 	struct rcu_data *rdp;
-	struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
+	struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
 	struct rcu_node *rnp;
 	struct rcu_state *rsp;
 	int tne;
@@ -1688,7 +1688,7 @@ static void rcu_prepare_for_idle(int cpu)
 		return;
 
 	/* If this is a no-CBs CPU, no callbacks, just return. */
-	if (rcu_is_nocb_cpu(cpu))
+	if (rcu_is_nocb_cpu(smp_processor_id()))
 		return;
 
 	/*
@@ -1712,7 +1712,7 @@ static void rcu_prepare_for_idle(int cpu)
 		return;
 	rdtp->last_accelerate = jiffies;
 	for_each_rcu_flavor(rsp) {
-		rdp = per_cpu_ptr(rsp->rda, cpu);
+		rdp = this_cpu_ptr(rsp->rda);
 		if (!*rdp->nxttail[RCU_DONE_TAIL])
 			continue;
 		rnp = rdp->mynode;