linux-kernel - [PATCH] x86/msi: Use guard() instead of mutex

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Message-Id: <20250901132105.649816-1-liaoyuanhong@vivo.com>
Date: Mon,  1 Sep 2025 21:21:02 +0800
From: Liao Yuanhong <liaoyuanhong@...o.com>
To: Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	"H. Peter Anvin" <hpa@...or.com>,
	Steve Wahl <steve.wahl@....com>,
	Wei Liu <wei.liu@...nel.org>,
	linux-kernel@...r.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND 64-BIT))
Cc: Liao Yuanhong <liaoyuanhong@...o.com>
Subject: [PATCH] x86/msi: Use guard() instead of mutex_lock() to simplify code

Using guard(mutex) instead of mutex_lock/mutex_unlock pair. Simplifies the
error handling to just return in case of error. No need for the 'out' label
anymore so remove it.

Signed-off-by: Liao Yuanhong <liaoyuanhong@...o.com>
---
 arch/x86/kernel/apic/msi.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/apic/msi.c b/arch/x86/kernel/apic/msi.c
index 66bc5d3e79db..e11523cfdbc5 100644
--- a/arch/x86/kernel/apic/msi.c
+++ b/arch/x86/kernel/apic/msi.c
@@ -346,9 +346,9 @@ static struct irq_domain *dmar_get_irq_domain(void)
 	static DEFINE_MUTEX(dmar_lock);
 	struct fwnode_handle *fn;
 
-	mutex_lock(&dmar_lock);
+	guard(mutex)(&dmar_lock);
 	if (dmar_domain)
-		goto out;
+		return dmar_domain;
 
 	fn = irq_domain_alloc_named_fwnode("DMAR-MSI");
 	if (fn) {
@@ -357,8 +357,7 @@ static struct irq_domain *dmar_get_irq_domain(void)
 		if (!dmar_domain)
 			irq_domain_free_fwnode(fn);
 	}
-out:
-	mutex_unlock(&dmar_lock);
+
 	return dmar_domain;
 }
 
-- 
2.34.1