linux-kernel - Re: [PATCH] MIPS: KVM: Fix a build warning about variable set but not used

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Date:   Thu, 19 Oct 2023 10:50:33 +0200
From:   Thomas Bogendoerfer <tsbogend@...ha.franken.de>
To:     Huacai Chen <chenhuacai@...ngson.cn>
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Huacai Chen <chenhuacai@...nel.org>, kvm@...r.kernel.org,
        linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jiaxun Yang <jiaxun.yang@...goat.com>, stable@...r.kernel.org,
        kernel test robot <lkp@...el.com>
Subject: Re: [PATCH] MIPS: KVM: Fix a build warning about variable set but
 not used

On Tue, Oct 10, 2023 at 04:54:34PM +0800, Huacai Chen wrote:
> After commit 411740f5422a ("KVM: MIPS/MMU: Implement KVM_CAP_SYNC_MMU")
> old_pte is no longer used in kvm_mips_map_page(). So remove it to fix a
> build warning about variable set but not used:
> 
>    arch/mips/kvm/mmu.c: In function 'kvm_mips_map_page':
> >> arch/mips/kvm/mmu.c:701:29: warning: variable 'old_pte' set but not used [-Wunused-but-set-variable]
>      701 |         pte_t *ptep, entry, old_pte;
>          |                             ^~~~~~~
> 
> Cc: stable@...r.kernel.org
> Fixes: 411740f5422a960 ("KVM: MIPS/MMU: Implement KVM_CAP_SYNC_MMU")
> Reported-by: kernel test robot <lkp@...el.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202310070530.aARZCSfh-lkp@intel.com/
> Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
> ---
>  arch/mips/kvm/mmu.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/arch/mips/kvm/mmu.c b/arch/mips/kvm/mmu.c
> index e8c08988ed37..cc09fd23aae3 100644
> --- a/arch/mips/kvm/mmu.c
> +++ b/arch/mips/kvm/mmu.c
> @@ -592,7 +592,7 @@ static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
>  	gfn_t gfn = gpa >> PAGE_SHIFT;
>  	int srcu_idx, err;
>  	kvm_pfn_t pfn;
> -	pte_t *ptep, entry, old_pte;
> +	pte_t *ptep, entry;
>  	bool writeable;
>  	unsigned long prot_bits;
>  	unsigned long mmu_seq;
> @@ -664,7 +664,6 @@ static int kvm_mips_map_page(struct kvm_vcpu *vcpu, unsigned long gpa,
>  	entry = pfn_pte(pfn, __pgprot(prot_bits));
>  
>  	/* Write the PTE */
> -	old_pte = *ptep;
>  	set_pte(ptep, entry);
>  
>  	err = 0;
> -- 
> 2.39.3

applied to mips-next.

Thomas.

-- 
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