linux-kernel - Re: [PATCH 1/3] iova: Remove some magazine pointer NULL checks

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Message-ID: <388efa0d-d8b8-a837-b301-ef04ba3d6e4e@arm.com>
Date:   Wed, 17 Aug 2022 11:36:25 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     John Garry <john.garry@...wei.com>, joro@...tes.org,
        will@...nel.org
Cc:     iommu@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] iova: Remove some magazine pointer NULL checks

On 2022-08-17 11:09, John Garry wrote:
> Since commit 32e92d9f6f87 ("iommu/iova: Separate out rcache init") it
> has not been possible to have NULL CPU rcache "loaded" or "prev" magazine
> pointers. As such, the checks in iova_magazine_full(),
> iova_magazine_empty(), and iova_magazine_free_pfns() may be dropped.

Reviewed-by: Robin Murphy <robin.murphy@....com>

> Signed-off-by: John Garry <john.garry@...wei.com>
> ---
>   drivers/iommu/iova.c | 7 ++-----
>   1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
> index 47d1983dfa2a..580fdf669922 100644
> --- a/drivers/iommu/iova.c
> +++ b/drivers/iommu/iova.c
> @@ -661,9 +661,6 @@ iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad)
>   	unsigned long flags;
>   	int i;
>   
> -	if (!mag)
> -		return;
> -
>   	spin_lock_irqsave(&iovad->iova_rbtree_lock, flags);
>   
>   	for (i = 0 ; i < mag->size; ++i) {
> @@ -683,12 +680,12 @@ iova_magazine_free_pfns(struct iova_magazine *mag, struct iova_domain *iovad)
>   
>   static bool iova_magazine_full(struct iova_magazine *mag)
>   {
> -	return (mag && mag->size == IOVA_MAG_SIZE);
> +	return mag->size == IOVA_MAG_SIZE;
>   }
>   
>   static bool iova_magazine_empty(struct iova_magazine *mag)
>   {
> -	return (!mag || mag->size == 0);
> +	return mag->size == 0;
>   }
>   
>   static unsigned long iova_magazine_pop(struct iova_magazine *mag,