linux-kernel - Re: [PATCH 6/6] vfio/iommu_type1: Drop parameter "pgsize" of update_user

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Date:   Fri, 15 Jan 2021 16:44:09 -0700
From:   Alex Williamson <alex.williamson@...hat.com>
To:     Keqian Zhu <zhukeqian1@...wei.com>
Cc:     <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <iommu@...ts.linux-foundation.org>, <kvm@...r.kernel.org>,
        <kvmarm@...ts.cs.columbia.edu>, Cornelia Huck <cohuck@...hat.com>,
        Will Deacon <will@...nel.org>, "Marc Zyngier" <maz@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Mark Rutland <mark.rutland@....com>,
        James Morse <james.morse@....com>,
        Robin Murphy <robin.murphy@....com>,
        Joerg Roedel <joro@...tes.org>,
        "Daniel Lezcano" <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Alexios Zavras <alexios.zavras@...el.com>,
        <wanghaibin.wang@...wei.com>, <jiangkunkun@...wei.com>
Subject: Re: [PATCH 6/6] vfio/iommu_type1: Drop parameter "pgsize" of
 update_user_bitmap

On Thu, 7 Jan 2021 12:44:01 +0800
Keqian Zhu <zhukeqian1@...wei.com> wrote:

> We always use the smallest supported page size of vfio_iommu as
> pgsize. Drop parameter "pgsize" of update_user_bitmap.
> 
> Signed-off-by: Keqian Zhu <zhukeqian1@...wei.com>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 82649a040148..bceda5e8baaa 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -978,10 +978,9 @@ static void vfio_update_pgsize_bitmap(struct vfio_iommu *iommu)
>  }
>  
>  static int update_user_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
> -			      struct vfio_dma *dma, dma_addr_t base_iova,
> -			      size_t pgsize)
> +			      struct vfio_dma *dma, dma_addr_t base_iova)
>  {
> -	unsigned long pgshift = __ffs(pgsize);
> +	unsigned long pgshift = __ffs(iommu->pgsize_bitmap);
>  	unsigned long nbits = dma->size >> pgshift;
>  	unsigned long bit_offset = (dma->iova - base_iova) >> pgshift;
>  	unsigned long copy_offset = bit_offset / BITS_PER_LONG;
> @@ -1046,7 +1045,7 @@ static int vfio_iova_dirty_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
>  		if (dma->iova > iova + size - 1)
>  			break;
>  
> -		ret = update_user_bitmap(bitmap, iommu, dma, iova, pgsize);
> +		ret = update_user_bitmap(bitmap, iommu, dma, iova);
>  		if (ret)
>  			return ret;
>  
> @@ -1192,7 +1191,7 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
>  
>  		if (unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
>  			ret = update_user_bitmap(bitmap->data, iommu, dma,
> -						 unmap->iova, pgsize);
> +						 unmap->iova);
>  			if (ret)
>  				break;
>  		}

Same as the previous, both call sites already have both pgsize and
pgshift, pass both rather than recalculate.  Thanks,

Alex