linux-kernel - [PATCH tip/core/rcu 08/12] rcu: Switch force_qs_rnp() to for_each_leaf_node_cpu

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Date:   Mon,  9 Dec 2019 20:07:37 -0800
From:   paulmck@...nel.org
To:     rcu@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, kernel-team@...com, mingo@...nel.org,
        jiangshanlai@...il.com, dipankar@...ibm.com,
        akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
        josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
        rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
        fweisbec@...il.com, oleg@...hat.com, joel@...lfernandes.org,
        "Paul E. McKenney" <paulmck@...nel.org>
Subject: [PATCH tip/core/rcu 08/12] rcu: Switch force_qs_rnp() to for_each_leaf_node_cpu_mask()

From: "Paul E. McKenney" <paulmck@...nel.org>

Currently, force_qs_rnp() uses a for_each_leaf_node_possible_cpu()
loop containing a check of the current CPU's bit in ->qsmask.
This works, but this commit saves three lines by instead using
for_each_leaf_node_cpu_mask(), which combines the functionality of
for_each_leaf_node_possible_cpu() and leaf_node_cpu_bit().  This commit
also replaces the use of the local variable "bit" with rdp->grpmask.

Signed-off-by: Paul E. McKenney <paulmck@...nel.org>
---
 kernel/rcu/tree.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index bbb60ed..d950764 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2298,14 +2298,11 @@ static void force_qs_rnp(int (*f)(struct rcu_data *rdp))
 			raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
 			continue;
 		}
-		for_each_leaf_node_possible_cpu(rnp, cpu) {
-			unsigned long bit = leaf_node_cpu_bit(rnp, cpu);
-			if ((rnp->qsmask & bit) != 0) {
-				rdp = per_cpu_ptr(&rcu_data, cpu);
-				if (f(rdp)) {
-					mask |= bit;
-					rcu_disable_urgency_upon_qs(rdp);
-				}
+		for_each_leaf_node_cpu_mask(rnp, cpu, rnp->qsmask) {
+			rdp = per_cpu_ptr(&rcu_data, cpu);
+			if (f(rdp)) {
+				mask |= rdp->grpmask;
+				rcu_disable_urgency_upon_qs(rdp);
 			}
 		}
 		if (mask != 0) {
-- 
2.9.5