irqchip/loongson-eiointc: 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() 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>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Link: https://lore.kernel.org/r/20240416085454.3547175-5-dawei.li@shingroup.cn

diff --git a/drivers/irqchip/irq-loongson-eiointc.c b/drivers/irqchip/irq-loongson-eiointc.c
index 4f5e6d21d77df865df197bc738f0889c869188de..c7ddebf312ad2c1395a2cfaec7dbf24e93e60fb0 100644 (file)
--- a/drivers/irqchip/irq-loongson-eiointc.c
+++ b/drivers/irqchip/irq-loongson-eiointc.c
@@ -93,19 +93,15 @@ static int eiointc_set_irq_affinity(struct irq_data *d, const struct cpumask *af
        unsigned int cpu;
        unsigned long flags;
        uint32_t vector, regaddr;
-       struct cpumask intersect_affinity;
        struct eiointc_priv *priv = d->domain->host_data;
 
        raw_spin_lock_irqsave(&affinity_lock, flags);
 
-       cpumask_and(&intersect_affinity, affinity, cpu_online_mask);
-       cpumask_and(&intersect_affinity, &intersect_affinity, &priv->cpuspan_map);
-
-       if (cpumask_empty(&intersect_affinity)) {
+       cpu = cpumask_first_and_and(&priv->cpuspan_map, affinity, cpu_online_mask);
+       if (cpu >= nr_cpu_ids) {
                raw_spin_unlock_irqrestore(&affinity_lock, flags);
                return -EINVAL;
        }
-       cpu = cpumask_first(&intersect_affinity);
 
        vector = d->hwirq;
        regaddr = EIOINTC_REG_ENABLE + ((vector >> 5) << 2);