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

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Message-Id: <20250901131604.646415-1-liaoyuanhong@vivo.com>
Date: Mon,  1 Sep 2025 21:16:04 +0800
From: Liao Yuanhong <liaoyuanhong@...o.com>
To: Vitaly Kuznetsov <vkuznets@...hat.com>,
	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:KVM X86 HYPER-V (KVM/hyper-v)),
	linux-kernel@...r.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND 64-BIT))
Cc: Liao Yuanhong <liaoyuanhong@...o.com>
Subject: [PATCH] KVM: x86: hyper-v: 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_unlock' label anymore so remove it.

Signed-off-by: Liao Yuanhong <liaoyuanhong@...o.com>
---
 arch/x86/kvm/hyperv.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index 72b19a88a776..a471900c7325 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1168,15 +1168,15 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm,
 	BUILD_BUG_ON(sizeof(tsc_seq) != sizeof(hv->tsc_ref.tsc_sequence));
 	BUILD_BUG_ON(offsetof(struct ms_hyperv_tsc_page, tsc_sequence) != 0);
 
-	mutex_lock(&hv->hv_lock);
+	guard(mutex)(&hv->hv_lock);
 
 	if (hv->hv_tsc_page_status == HV_TSC_PAGE_BROKEN ||
 	    hv->hv_tsc_page_status == HV_TSC_PAGE_SET ||
 	    hv->hv_tsc_page_status == HV_TSC_PAGE_UNSET)
-		goto out_unlock;
+		return;
 
 	if (!(hv->hv_tsc_page & HV_X64_MSR_TSC_REFERENCE_ENABLE))
-		goto out_unlock;
+		return;
 
 	gfn = hv->hv_tsc_page >> HV_X64_MSR_TSC_REFERENCE_ADDRESS_SHIFT;
 	/*
@@ -1192,7 +1192,7 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm,
 			goto out_err;
 
 		hv->hv_tsc_page_status = HV_TSC_PAGE_SET;
-		goto out_unlock;
+		return;
 	}
 
 	/*
@@ -1228,12 +1228,10 @@ void kvm_hv_setup_tsc_page(struct kvm *kvm,
 		goto out_err;
 
 	hv->hv_tsc_page_status = HV_TSC_PAGE_SET;
-	goto out_unlock;
+	return;
 
 out_err:
 	hv->hv_tsc_page_status = HV_TSC_PAGE_BROKEN;
-out_unlock:
-	mutex_unlock(&hv->hv_lock);
 }
 
 void kvm_hv_request_tsc_page_update(struct kvm *kvm)
-- 
2.34.1