[PATCH v3 09/10] perf/qcom_l2: Avoid placing cpumask on the stack

From: Dawei Li
Date: Wed Apr 03 2024 - 12:04:56 EST


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_any_and_but() to avoid the need for a temporary cpumask on
the stack.

Suggested-by: Mark Rutland <mark.rutland@xxxxxxx>
Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Dawei Li <dawei.li@xxxxxxxxxxxx>
---
drivers/perf/qcom_l2_pmu.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/perf/qcom_l2_pmu.c b/drivers/perf/qcom_l2_pmu.c
index 148df5ae8ef8..b5a44dc1dc3a 100644
--- a/drivers/perf/qcom_l2_pmu.c
+++ b/drivers/perf/qcom_l2_pmu.c
@@ -801,9 +801,8 @@ static int l2cache_pmu_online_cpu(unsigned int cpu, struct hlist_node *node)

static int l2cache_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
{
- struct cluster_pmu *cluster;
struct l2cache_pmu *l2cache_pmu;
- cpumask_t cluster_online_cpus;
+ struct cluster_pmu *cluster;
unsigned int target;

l2cache_pmu = hlist_entry_safe(node, struct l2cache_pmu, node);
@@ -820,9 +819,8 @@ static int l2cache_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
cluster->on_cpu = -1;

/* Any other CPU for this cluster which is still online */
- cpumask_and(&cluster_online_cpus, &cluster->cluster_cpus,
- cpu_online_mask);
- target = cpumask_any_but(&cluster_online_cpus, cpu);
+ target = cpumask_any_and_but(&cluster->cluster_cpus,
+ cpu_online_mask, cpu);
if (target >= nr_cpu_ids) {
disable_irq(cluster->irq);
return 0;
--
2.27.0