linux-kernel - Re: [PATCH] kvm: i8254: remove redundant assignment to pointer s

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Message-ID: <875zbzb9s8.fsf@vitty.brq.redhat.com>
Date:   Wed, 10 Jun 2020 10:32:55 +0200
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     Colin King <colin.king@...onical.com>
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H . Peter Anvin" <hpa@...or.com>,
        kvm@...r.kernel.org
Subject: Re: [PATCH] kvm: i8254: remove redundant assignment to pointer s

Colin King <colin.king@...onical.com> writes:

> From: Colin Ian King <colin.king@...onical.com>
>
> The pointer s is being assigned a value that is never read, the
> assignment is redundant and can be removed.
>
> Addresses-Coverity: ("Unused value")
> Signed-off-by: Colin Ian King <colin.king@...onical.com>

It seems it wasn't used since the very beginning,

Fixes: 7837699fa6d7 ("KVM: In kernel PIT model")

QEMU code (from where KVM's implementation originates), however, 
does make use of 's' here as it open codes pit_latch_status().

> ---
>  arch/x86/kvm/i8254.c | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
> index febca334c320..a6e218c6140d 100644
> --- a/arch/x86/kvm/i8254.c
> +++ b/arch/x86/kvm/i8254.c
> @@ -462,7 +462,6 @@ static int pit_ioport_write(struct kvm_vcpu *vcpu,
>  		if (channel == 3) {
>  			/* Read-Back Command. */
>  			for (channel = 0; channel < 3; channel++) {
> -				s = &pit_state->channels[channel];
>  				if (val & (2 << channel)) {
>  					if (!(val & 0x20))
>  						pit_latch_count(pit, channel);

Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>

-- 
Vitaly