cpuidle: Avoid explicit cpumask allocation on stack

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@shingroup.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240416085454.3547175-8-dawei.li@shingroup.cn

diff --git a/drivers/cpuidle/coupled.c b/drivers/cpuidle/coupled.c
index 9acde71558d5101a1d98daeb8e16c185ff8ca98b..bb8761c8a42e46264a8a80e021319334d589b398 100644 (file)
--- 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 @@ out:
 
 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);
 }
 
 /**