linux-kernel - [PATCH v2 2/7] irqchip/irq-bcm6345-l1: Avoid explicit cpumask allocation on stack

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Message-Id: <20240416085454.3547175-3-dawei.li@shingroup.cn>
Date: Tue, 16 Apr 2024 16:54:49 +0800
From: Dawei Li <dawei.li@...ngroup.cn>
To: tglx@...utronix.de,
	yury.norov@...il.com,
	rafael@...nel.org
Cc: akpm@...ux-foundation.org,
	maz@...nel.org,
	florian.fainelli@...adcom.com,
	chenhuacai@...nel.org,
	jiaxun.yang@...goat.com,
	anup@...infault.org,
	palmer@...belt.com,
	samuel.holland@...ive.com,
	linux@...musvillemoes.dk,
	daniel.lezcano@...aro.org,
	linux-kernel@...r.kernel.org,
	Dawei Li <dawei.li@...ngroup.cn>
Subject: [PATCH v2 2/7] irqchip/irq-bcm6345-l1: 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@...ngroup.cn>
---
 drivers/irqchip/irq-bcm6345-l1.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/irqchip/irq-bcm6345-l1.c b/drivers/irqchip/irq-bcm6345-l1.c
index eb02d203c963..90daa274ef23 100644
--- a/drivers/irqchip/irq-bcm6345-l1.c
+++ b/drivers/irqchip/irq-bcm6345-l1.c
@@ -192,14 +192,10 @@ static int bcm6345_l1_set_affinity(struct irq_data *d,
 	u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
 	unsigned int old_cpu = cpu_for_irq(intc, d);
 	unsigned int new_cpu;
-	struct cpumask valid;
 	unsigned long flags;
 	bool enabled;
 
-	if (!cpumask_and(&valid, &intc->cpumask, dest))
-		return -EINVAL;
-
-	new_cpu = cpumask_any_and(&valid, cpu_online_mask);
+	new_cpu = cpumask_first_and_and(&intc->cpumask, dest, cpu_online_mask);
 	if (new_cpu >= nr_cpu_ids)
 		return -EINVAL;
 
-- 
2.27.0