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

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Message-Id: <20250901131822.647802-1-liaoyuanhong@vivo.com>
Date: Mon,  1 Sep 2025 21:18:21 +0800
From: Liao Yuanhong <liaoyuanhong@...o.com>
To: Sean Christopherson <seanjc@...gle.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	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>,
	kvm@...r.kernel.org (open list:KERNEL VIRTUAL MACHINE FOR X86 (KVM/x86)),
	linux-kernel@...r.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND 64-BIT))
Cc: Liao Yuanhong <liaoyuanhong@...o.com>
Subject: [PATCH] x86/apic: KVM: 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
and variable 'ret' anymore so remove it.

Signed-off-by: Liao Yuanhong <liaoyuanhong@...o.com>
---
 arch/x86/kvm/lapic.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index ed636c1f5e58..fa52622bcf5f 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2683,24 +2683,20 @@ void kvm_apic_update_apicv(struct kvm_vcpu *vcpu)
 int kvm_alloc_apic_access_page(struct kvm *kvm)
 {
 	void __user *hva;
-	int ret = 0;
 
-	mutex_lock(&kvm->slots_lock);
+	guard(mutex)(&kvm->slots_lock);
 	if (kvm->arch.apic_access_memslot_enabled ||
 	    kvm->arch.apic_access_memslot_inhibited)
-		goto out;
+		return 0;
 
 	hva = __x86_set_memory_region(kvm, APIC_ACCESS_PAGE_PRIVATE_MEMSLOT,
 				      APIC_DEFAULT_PHYS_BASE, PAGE_SIZE);
-	if (IS_ERR(hva)) {
-		ret = PTR_ERR(hva);
-		goto out;
-	}
+	if (IS_ERR(hva))
+		return PTR_ERR(hva);
 
 	kvm->arch.apic_access_memslot_enabled = true;
-out:
-	mutex_unlock(&kvm->slots_lock);
-	return ret;
+
+	return 0;
 }
 EXPORT_SYMBOL_GPL(kvm_alloc_apic_access_page);
 
-- 
2.34.1