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

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Date:   Sat, 25 Jan 2020 10:42:40 -0000
From:   "tip-bot2 for Paul E. McKenney" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     "Paul E. McKenney" <paulmck@...nel.org>, x86 <x86@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: [tip: core/rcu] rcu: Switch force_qs_rnp() to for_each_leaf_node_cpu_mask()

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     7441e7661d6586ae36329b7956e4d713d81e9903
Gitweb:        https://git.kernel.org/tip/7441e7661d6586ae36329b7956e4d713d81e9903
Author:        Paul E. McKenney <paulmck@...nel.org>
AuthorDate:    Wed, 30 Oct 2019 09:37:11 -07:00
Committer:     Paul E. McKenney <paulmck@...nel.org>
CommitterDate: Fri, 24 Jan 2020 10:33:51 -08:00

rcu: Switch force_qs_rnp() to for_each_leaf_node_cpu_mask()

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) {