linux-kernel - [PATCH v2 6/7] sparc/leon: Remove on-stack cpumask var

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Date: Sat, 20 Apr 2024 13:15:46 +0800
From: Dawei Li <dawei.li@...ngroup.cn>
To: davem@...emloft.net,
	andreas@...sler.com
Cc: sparclinux@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	sam@...nborg.org,
	Dawei Li <dawei.li@...ngroup.cn>
Subject: [PATCH v2 6/7] sparc/leon: Remove on-stack cpumask var

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_subset() and cpumask_first_and() to avoid the need for a
temporary cpumask on the stack.

Signed-off-by: Dawei Li <dawei.li@...ngroup.cn>
---
 arch/sparc/kernel/leon_kernel.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/sparc/kernel/leon_kernel.c b/arch/sparc/kernel/leon_kernel.c
index 4c61da491fee..0070655041bb 100644
--- a/arch/sparc/kernel/leon_kernel.c
+++ b/arch/sparc/kernel/leon_kernel.c
@@ -106,13 +106,10 @@ unsigned long leon_get_irqmask(unsigned int irq)
 #ifdef CONFIG_SMP
 static int irq_choose_cpu(const struct cpumask *affinity)
 {
-	cpumask_t mask;
+	unsigned int cpu = cpumask_first_and(affinity, cpu_online_mask);
 
-	cpumask_and(&mask, cpu_online_mask, affinity);
-	if (cpumask_equal(&mask, cpu_online_mask) || cpumask_empty(&mask))
-		return boot_cpu_id;
-	else
-		return cpumask_first(&mask);
+	return cpumask_subset(cpu_online_mask, affinity) || cpu >= nr_cpu_ids ?
+	       boot_cpu_id : cpu;
 }
 #else
 #define irq_choose_cpu(affinity) boot_cpu_id
-- 
2.27.0