linux-kernel - [PATCH 3/6] KVM: x86: remove always equal to 0 return val of kvm_vm_ioctl_get

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Date:   Sat, 7 Dec 2019 17:25:20 +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 3/6] KVM: x86: remove always equal to 0 return val of kvm_vm_ioctl_get_pit2()

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

The return val of kvm_vm_ioctl_get_pit2() 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 | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5628dceb9fa5..637d5c6b92be 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4621,15 +4621,17 @@ static void kvm_vm_ioctl_set_pit(struct kvm *kvm, struct kvm_pit_state *ps)
 	mutex_unlock(&pit->pit_state.lock);
 }
 
-static int kvm_vm_ioctl_get_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
+static void kvm_vm_ioctl_get_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
 {
+	BUILD_BUG_ON(sizeof(ps->channels) !=
+		     sizeof(kvm->arch.vpit->pit_state.channels));
+
 	mutex_lock(&kvm->arch.vpit->pit_state.lock);
 	memcpy(ps->channels, &kvm->arch.vpit->pit_state.channels,
 		sizeof(ps->channels));
 	ps->flags = kvm->arch.vpit->pit_state.flags;
 	mutex_unlock(&kvm->arch.vpit->pit_state.lock);
 	memset(&ps->reserved, 0, sizeof(ps->reserved));
-	return 0;
 }
 
 static int kvm_vm_ioctl_set_pit2(struct kvm *kvm, struct kvm_pit_state2 *ps)
@@ -5003,9 +5005,7 @@ long kvm_arch_vm_ioctl(struct file *filp,
 		r = -ENXIO;
 		if (!kvm->arch.vpit)
 			goto out;
-		r = kvm_vm_ioctl_get_pit2(kvm, &u.ps2);
-		if (r)
-			goto out;
+		kvm_vm_ioctl_get_pit2(kvm, &u.ps2);
 		r = -EFAULT;
 		if (copy_to_user(argp, &u.ps2, sizeof(u.ps2)))
 			goto out;
-- 
2.19.1