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From:   Vitaly Kuznetsov <vkuznets@redhat.com>
To:     maowenan <maowenan@huawei.com>
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        kernel-janitors@vger.kernel.org, pbonzini@redhat.com,
        rkrcmar@redhat.com, sean.j.christopherson@intel.com,
        wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org,
        tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com
Subject: Re: [PATCH -next] KVM: x86: remove set but not used variable 'called'
In-Reply-To: <b164198f-2418-5f24-3f2f-cf8027af14b1@huawei.com>
References: <20191119030640.25097-1-maowenan@huawei.com> <87o8x8gjr5.fsf@vitty.brq.redhat.com> <b164198f-2418-5f24-3f2f-cf8027af14b1@huawei.com>
Date:   Tue, 19 Nov 2019 14:27:45 +0100
Message-ID: <877e3wgfn2.fsf@vitty.brq.redhat.com>
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maowenan <maowenan@huawei.com> writes:

> =E5=9C=A8 2019/11/19 19:58, Vitaly Kuznetsov =E5=86=99=E9=81=93:
>> Mao Wenan <maowenan@huawei.com> writes:
>>=20
>>> Fixes gcc '-Wunused-but-set-variable' warning:
>>>
>>> arch/x86/kvm/x86.c: In function kvm_make_scan_ioapic_request_mask:
>>> arch/x86/kvm/x86.c:7911:7: warning: variable called set but not
>>> used [-Wunused-but-set-variable]
>>>
>>> It is not used since commit 7ee30bc132c6 ("KVM: x86: deliver KVM
>>> IOAPIC scan request to target vCPUs")
>>=20
>> Better expressed as=20
>>=20
>> Fixes: 7ee30bc132c6 ("KVM: x86: deliver KVM IOAPIC scan request to targe=
t vCPUs")
>
> This is just a cleanup, so Fixes tag is no need.
>>=20

Just a cleanup -- unless we compile with '-Werror'.

>>>
>>> Signed-off-by: Mao Wenan <maowenan@huawei.com>
>>> ---
>>>  arch/x86/kvm/x86.c | 5 ++---
>>>  1 file changed, 2 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>>> index 0d0a682..870f0bc 100644
>>> --- a/arch/x86/kvm/x86.c
>>> +++ b/arch/x86/kvm/x86.c
>>> @@ -7908,12 +7908,11 @@ void kvm_make_scan_ioapic_request_mask(struct k=
vm *kvm,
>>>  =09=09=09=09       unsigned long *vcpu_bitmap)
>>>  {
>>>  =09cpumask_var_t cpus;
>>> -=09bool called;
>>> =20
>>>  =09zalloc_cpumask_var(&cpus, GFP_ATOMIC);
>>> =20
>>> -=09called =3D kvm_make_vcpus_request_mask(kvm, KVM_REQ_SCAN_IOAPIC,
>>> -=09=09=09=09=09     vcpu_bitmap, cpus);
>>> +=09kvm_make_vcpus_request_mask(kvm, KVM_REQ_SCAN_IOAPIC,
>>> +=09=09=09=09    vcpu_bitmap, cpus);
>>=20
>> IMHO as kvm_make_vcpus_request_mask() returns value it would probably
>> make sense to explicitly show that we're not interested in the result,
>>=20
>> (void)kvm_make_vcpus_request_mask()
>
> thanks, but I think is no need to add (void) before kvm_make_vcpus_reques=
t_mask()
> because we are not interested in it's return value.

Hm, that's exactly the reason why I suggested adding it there :-) Not a
big deal, feel free to ignore.

--=20
Vitaly