linux-kernel - Re: [PATCH] KVM: x86/mmu: remove unnecessary flush

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Message-ID: <YkcFJZW0r+OQmQwz@google.com>
Date:   Fri, 1 Apr 2022 13:59:01 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     cgel.zte@...il.com
Cc:     pbonzini@...hat.com, vkuznets@...hat.com, wanpengli@...cent.com,
        jmattson@...gle.com, joro@...tes.org, tglx@...utronix.de,
        mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com,
        x86@...nel.org, hpa@...or.com, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Lv Ruyi <lv.ruyi@....com.cn>,
        Zeal Robot <zealci@....com.cn>
Subject: Re: [PATCH] KVM: x86/mmu: remove unnecessary flush_workqueue()

On Fri, Apr 01, 2022, cgel.zte@...il.com wrote:
> From: Lv Ruyi <lv.ruyi@....com.cn>
> 
> All work currently pending will be done first by calling destroy_workqueue,
> so there is unnecessary to flush it explicitly.
> 
> Reported-by: Zeal Robot <zealci@....com.cn>

Good bot :-)

> Signed-off-by: Lv Ruyi <lv.ruyi@....com.cn>
> ---
>  arch/x86/kvm/mmu/tdp_mmu.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index a2f9a34a0168..b822677ee3da 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -51,7 +51,6 @@ void kvm_mmu_uninit_tdp_mmu(struct kvm *kvm)
>  	if (!kvm->arch.tdp_mmu_enabled)
>  		return;
>  
> -	flush_workqueue(kvm->arch.tdp_mmu_zap_wq);

Might be worth adding a comment calling out that this drains the queue.  Either way,

Reviewed-by: Sean Christopherson <seanjc@...gle.com>