linux-kernel - Re: [PATCH 4/4] KVM: PPC: Book3S HV: Remove redundant parameter from resize_hpt

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Message-ID: <20171130035331.GR3023@umbus.fritz.box>
Date:   Thu, 30 Nov 2017 14:53:31 +1100
From:   David Gibson <david@...son.dropbear.id.au>
To:     Serhii Popovych <spopovyc@...hat.com>
Cc:     linux-kernel@...r.kernel.org, michael@...erman.id.au,
        paulus@...ba.org, linuxppc-dev@...ts.ozlabs.org,
        kvm-ppc@...r.kernel.org
Subject: Re: [PATCH 4/4] KVM: PPC: Book3S HV: Remove redundant parameter from
 resize_hpt_release()

On Wed, Nov 29, 2017 at 11:38:26AM -0500, Serhii Popovych wrote:
> There is no need to pass it explicitly from the caller:
> struct kvm_resize_hpt already contains it.
> 
> Additional benefit from this change is that BUG_ON()
> assertion now checks that mutex is held on kvm instance
> associated with resize structure we going to release.
> 
> Also kill check for resize being NULL to make code
> simpler and we called with resize != NULL in all
> places except kvm_vm_ioctl_resize_hpt_commit().
> 
> Signed-off-by: Serhii Popovych <spopovyc@...hat.com>

Reviewed-by: David Gibson <david@...son.dropbear.id.au>

> ---
>  arch/powerpc/kvm/book3s_64_mmu_hv.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> index 690f061..a74a0ad 100644
> --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c
> +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c
> @@ -1415,12 +1415,11 @@ static void resize_hpt_pivot(struct kvm_resize_hpt *resize)
>  	resize_hpt_debug(resize, "resize_hpt_pivot() done\n");
>  }
>  
> -static void resize_hpt_release(struct kvm *kvm, struct kvm_resize_hpt *resize)
> +static void resize_hpt_release(struct kvm_resize_hpt *resize)
>  {
> -	BUG_ON(!mutex_is_locked(&kvm->lock));
> +	struct kvm *kvm = resize->kvm;
>  
> -	if (!resize)
> -		return;
> +	BUG_ON(!mutex_is_locked(&kvm->lock));
>  
>  	if (resize->error != -EBUSY) {
>  		kvmppc_free_hpt(&resize->hpt);
> @@ -1469,7 +1468,7 @@ static void resize_hpt_prepare_work(struct work_struct *work)
>  	resize->error = err;
>  
>  	if (kvm->arch.resize_hpt != resize)
> -		resize_hpt_release(kvm, resize);
> +		resize_hpt_release(resize);
>  
>  	mutex_unlock(&kvm->lock);
>  }
> @@ -1499,13 +1498,13 @@ long kvm_vm_ioctl_resize_hpt_prepare(struct kvm *kvm,
>  			if (ret == -EBUSY)
>  				ret = 100; /* estimated time in ms */
>  			else if (ret)
> -				resize_hpt_release(kvm, resize);
> +				resize_hpt_release(resize);
>  
>  			goto out;
>  		}
>  
>  		/* not suitable, cancel it */
> -		resize_hpt_release(kvm, resize);
> +		resize_hpt_release(resize);
>  	}
>  
>  	ret = 0;
> @@ -1590,7 +1589,8 @@ long kvm_vm_ioctl_resize_hpt_commit(struct kvm *kvm,
>  	kvm->arch.mmu_ready = 1;
>  	smp_mb();
>  out_no_hpt:
> -	resize_hpt_release(kvm, resize);
> +	if (resize)
> +		resize_hpt_release(resize);
>  	mutex_unlock(&kvm->lock);
>  	return ret;
>  }

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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