linux-kernel - [PATCH 2/6] KVM: x86: remove always equal to 0 return val of kvm_vm_ioctl_set

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Date:   Sat, 7 Dec 2019 17:25:19 +0800
From:   linmiaohe <linmiaohe@...wei.com>
To:     <pbonzini@...hat.com>, <rkrcmar@...hat.com>,
        <sean.j.christopherson@...el.com>, <vkuznets@...hat.com>,
        <wanpengli@...cent.com>, <jmattson@...gle.com>, <joro@...tes.org>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
        <hpa@...or.com>
CC:     <linmiaohe@...wei.com>, <kvm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <x86@...nel.org>
Subject: [PATCH 2/6] KVM: x86: remove always equal to 0 return val of kvm_vm_ioctl_set_pit()

From: Miaohe Lin <linmiaohe@...wei.com>

The return val of kvm_vm_ioctl_set_pit() is always equal to 0, which means
there is no way to failed with this function. So remove the return val as
it's unnecessary to check against it.
Also add BUILD_BUG_ON to guard against channels size changed unexpectly.

Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
 arch/x86/kvm/x86.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 732f03c19fdc..5628dceb9fa5 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4607,17 +4607,18 @@ static void kvm_vm_ioctl_get_pit(struct kvm *kvm, struct kvm_pit_state *ps)
 	mutex_unlock(&kps->lock);
 }
 
-static int kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
+static void kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
 {
 	int i;
 	struct kvm_pit *pit = kvm->arch.vpit;
 
+	BUILD_BUG_ON(sizeof(*ps) != sizeof(pit->pit_state.channels));
+
 	mutex_lock(&pit->pit_state.lock);
 	memcpy(&pit->pit_state.channels, ps, sizeof(*ps));
 	for (i = 0; i < 3; i++)
 		kvm_pit_load_count(pit, i, ps->channels[i].count, 0);
 	mutex_unlock(&pit->pit_state.lock);
-	return 0;
 }
 
 static int kvm_vm_ioctl_get_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
@@ -4994,7 +4995,8 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		r = -ENXIO;
 		if (!kvm->arch.vpit)
 			goto out;
-		r = kvm_vm_ioctl_set_pit(kvm, &u.ps);
+		kvm_vm_ioctl_set_pit(kvm, &u.ps);
+		r = 0;
 		break;
 	}
 	case KVM_GET_PIT2: {
-- 
2.19.1