[PATCH v2 7/7] cpuidle: Avoid explicit cpumask allocation on stack

[Dawei Li]

In general it's preferable to avoid placing cpumasks on the stack, as
for large values of NR_CPUS these can consume significant amounts of
stack space and make stack overflows more likely.

Use cpumask_first_and_and() and cpumask_weight_and() to avoid the need
for a temporary cpumask on the stack.

Signed-off-by: Dawei Li <dawei.li@xxxxxxxxxxxx>
---
 drivers/cpuidle/coupled.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
index 9acde71558d5..bb8761c8a42e 100644
--- a/drivers/cpuidle/coupled.c
+++ b/drivers/cpuidle/coupled.c
@@ -439,13 +439,8 @@ static int cpuidle_coupled_clear_pokes(int cpu)
 
 static bool cpuidle_coupled_any_pokes_pending(struct cpuidle_coupled *coupled)
 {
-	cpumask_t cpus;
-	int ret;
-
-	cpumask_and(&cpus, cpu_online_mask, &coupled->coupled_cpus);
-	ret = cpumask_and(&cpus, &cpuidle_coupled_poke_pending, &cpus);
-
-	return ret;
+	return cpumask_first_and_and(cpu_online_mask, &coupled->coupled_cpus,
+				     &cpuidle_coupled_poke_pending) < nr_cpu_ids;
 }
 
 /**
@@ -626,9 +621,7 @@ int cpuidle_enter_state_coupled(struct cpuidle_device *dev,
 
 static void cpuidle_coupled_update_online_cpus(struct cpuidle_coupled *coupled)
 {
-	cpumask_t cpus;
-	cpumask_and(&cpus, cpu_online_mask, &coupled->coupled_cpus);
-	coupled->online_count = cpumask_weight(&cpus);
+	coupled->online_count = cpumask_weight_and(cpu_online_mask, &coupled->coupled_cpus);
 }
 
 /**
-- 
2.27.0