Received-SPF: pass (google.com: domain of linux-kernel+bounces-152142-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
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 v2 2/7] sparc/irq: Remove on-stack cpumask var
Date: Sat, 20 Apr 2024 13:15:42 +0800
Message-Id: <20240420051547.3681642-3-dawei.li@shingroup.cn>
In-Reply-To: <20240420051547.3681642-1-dawei.li@shingroup.cn>
References: <20240420051547.3681642-1-dawei.li@shingroup.cn>
Precedence: bulk
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Feedback-ID: bizesmtp:shingroup.cn:qybglogicsvrgz:qybglogicsvrgz5a-1

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.

- Both 2 arguments of cpumask_equal() is constant and free of change, no
  need to allocate extra cpumask variables.

- Merge cpumask_and(), cpumask_first() and cpumask_empty() into
  cpumask_first_and().

Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
---
 arch/sparc/kernel/irq_64.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c
index 5280e325d4d6..01ee800efde3 100644
--- a/arch/sparc/kernel/irq_64.c
+++ b/arch/sparc/kernel/irq_64.c
@@ -349,17 +349,13 @@ static unsigned int sun4u_compute_tid(unsigned long imap, unsigned long cpuid)
 #ifdef CONFIG_SMP
 static int irq_choose_cpu(unsigned int irq, const struct cpumask *affinity)
 {
-	cpumask_t mask;
 	int cpuid;
 
-	cpumask_copy(&mask, affinity);
-	if (cpumask_equal(&mask, cpu_online_mask)) {
+	if (cpumask_equal(affinity, cpu_online_mask)) {
 		cpuid = map_to_cpu(irq);
 	} else {
-		cpumask_t tmp;
-
-		cpumask_and(&tmp, cpu_online_mask, &mask);
-		cpuid = cpumask_empty(&tmp) ? map_to_cpu(irq) : cpumask_first(&tmp);
+		cpuid = cpumask_first_and(affinity, cpu_online_mask);
+		cpuid = cpuid < nr_cpu_ids ? cpuid : map_to_cpu(irq);
 	}
 
 	return cpuid;
-- 
2.27.0