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From: Dawei Li <dawei.li@shingroup.cn>
To: davem@davemloft.net, andreas@gaisler.com
Cc: sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org,
	sam@ravnborg.org, Dawei Li <dawei.li@shingroup.cn>
Subject: [PATCH v3 6/6] sparc/leon: Remove on-stack cpumask var
Date: Tue, 23 Apr 2024 16:30:43 +0800	[thread overview]
Message-ID: <20240423083043.3735921-7-dawei.li@shingroup.cn> (raw)
In-Reply-To: <20240423083043.3735921-1-dawei.li@shingroup.cn>

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@shingroup.cn>
---
 arch/sparc/kernel/leon_kernel.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/sparc/kernel/leon_kernel.c b/arch/sparc/kernel/leon_kernel.c
index 4c61da491fee..a43cf794bb1e 100644
--- a/arch/sparc/kernel/leon_kernel.c
+++ b/arch/sparc/kernel/leon_kernel.c
@@ -106,13 +106,12 @@ 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))
+	if (cpumask_subset(cpu_online_mask, affinity) || cpu >= nr_cpu_ids)
 		return boot_cpu_id;
 	else
-		return cpumask_first(&mask);
+		return cpu;
 }
 #else
 #define irq_choose_cpu(affinity) boot_cpu_id
-- 
2.27.0


  parent reply	other threads:[~2024-04-23  8:31 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-23  8:30 [PATCH v3 0/6] Remove onstack cpumask var for sparc Dawei Li
2024-04-23  8:30 ` [PATCH v3 1/6] sparc/srmmu: Remove on-stack cpumask var Dawei Li
2024-04-23  8:30 ` [PATCH v3 2/6] sparc/irq: " Dawei Li
2024-04-23  8:30 ` [PATCH v3 3/6] sparc/of: " Dawei Li
2024-04-23  8:30 ` [PATCH v3 4/6] sparc/pci_msi: " Dawei Li
2024-04-23  8:30 ` [PATCH v3 5/6] sparc/init: " Dawei Li
2024-04-23 17:32   ` Sam Ravnborg
2024-04-23  8:30 ` Dawei Li [this message]
2024-04-23 17:29   ` [PATCH v3 6/6] sparc/leon: " Sam Ravnborg

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