linux-kernel - [tip: irq/core] irqchip/sifive-plic: Avoid explicit cpumask allocation on stack

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Message-ID: <171398904640.10875.11548457486987058733.tip-bot2@tip-bot2>
Date: Wed, 24 Apr 2024 20:04:06 -0000
From: "tip-bot2 for Dawei Li" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Dawei Li <dawei.li@...ngroup.cn>, Thomas Gleixner <tglx@...utronix.de>,
 Anup Patel <anup@...infault.org>, x86@...nel.org,
 linux-kernel@...r.kernel.org, maz@...nel.org
Subject: [tip: irq/core] irqchip/sifive-plic: Avoid explicit cpumask
 allocation on stack

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     a7fb69ffd7ce438a259b2f9fbcebc62f5caf2d4f
Gitweb:        https://git.kernel.org/tip/a7fb69ffd7ce438a259b2f9fbcebc62f5caf2d4f
Author:        Dawei Li <dawei.li@...ngroup.cn>
AuthorDate:    Tue, 16 Apr 2024 16:54:53 +08:00
Committer:     Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Wed, 24 Apr 2024 21:23:49 +02:00

irqchip/sifive-plic: 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>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Anup Patel <anup@...infault.org>
Link: https://lore.kernel.org/r/20240416085454.3547175-7-dawei.li@shingroup.cn

---
 drivers/irqchip/irq-sifive-plic.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index f3d4cb9..8fb183c 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -164,15 +164,12 @@ static int plic_set_affinity(struct irq_data *d,
 			     const struct cpumask *mask_val, bool force)
 {
 	unsigned int cpu;
-	struct cpumask amask;
 	struct plic_priv *priv = irq_data_get_irq_chip_data(d);
 
-	cpumask_and(&amask, &priv->lmask, mask_val);
-
 	if (force)
-		cpu = cpumask_first(&amask);
+		cpu = cpumask_first_and(&priv->lmask, mask_val);
 	else
-		cpu = cpumask_any_and(&amask, cpu_online_mask);
+		cpu = cpumask_first_and_and(&priv->lmask, mask_val, cpu_online_mask);
 
 	if (cpu >= nr_cpu_ids)
 		return -EINVAL;