linux-kernel - Re: [PATCH 2/2] iommu/arm-smmu-v3: Simplify memory allocation

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Message-ID: <f315aea5-b088-62ad-2234-81e8c0b13f74@arm.com>
Date:   Mon, 7 Feb 2022 10:56:41 +0000
From:   Robin Murphy <robin.murphy@....com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Will Deacon <will@...nel.org>, Joerg Roedel <joro@...tes.org>
Cc:     linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        iommu@...ts.linux-foundation.org
Subject: Re: [PATCH 2/2] iommu/arm-smmu-v3: Simplify memory allocation

On 2022-02-05 17:11, Christophe JAILLET wrote:
> Use devm_bitmap_zalloc() instead of hand writing it.

Heh, that reminds me that I have more or less the same patch sat locally 
somewhere, except IIRC I took it further and removed the unhelpful error 
message and pruned the local variables as well - I think that would 
still be my preference here (or I could dig out my patch and post it if 
you like).

Cheers,
Robin.

> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> ---
> This is NOT compile tested.
> I don't have the needed cross compiling tools.
> ---
>   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 10 ++--------
>   1 file changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 14d06aad0726..ba0e7f1f7dbf 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -2911,12 +2911,6 @@ static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
>   	return 0;
>   }
>   
> -static void arm_smmu_cmdq_free_bitmap(void *data)
> -{
> -	unsigned long *bitmap = data;
> -	bitmap_free(bitmap);
> -}
> -
>   static int arm_smmu_cmdq_init(struct arm_smmu_device *smmu)
>   {
>   	int ret = 0;
> @@ -2927,13 +2921,13 @@ static int arm_smmu_cmdq_init(struct arm_smmu_device *smmu)
>   	atomic_set(&cmdq->owner_prod, 0);
>   	atomic_set(&cmdq->lock, 0);
>   
> -	bitmap = (atomic_long_t *)bitmap_zalloc(nents, GFP_KERNEL);
> +	bitmap = (atomic_long_t *)devm_bitmap_zalloc(smmu->dev, nents,
> +						     GFP_KERNEL);
>   	if (!bitmap) {
>   		dev_err(smmu->dev, "failed to allocate cmdq bitmap\n");
>   		ret = -ENOMEM;
>   	} else {
>   		cmdq->valid_map = bitmap;
> -		devm_add_action(smmu->dev, arm_smmu_cmdq_free_bitmap, bitmap);
>   	}
>   
>   	return ret;