From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Subject: Re: [PATCH v2 3/5] ARM: dma-mapping: Implement
	arch_iommu_detach_device()
Date: Wed, 25 Apr 2018 08:20:49 -0700
Message-ID: <20180425152049.GD16075@infradead.org>
References: <20180425101051.15349-1-thierry.reding@gmail.com>
	<20180425101051.15349-3-thierry.reding@gmail.com>
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To: Thierry Reding <thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, Russell King <linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org>, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Daniel Vetter <daniel-/w4YWyX8dFk@public.gmane.org>, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
List-Id: linux-tegra@vger.kernel.org

> +void arch_iommu_detach_device(struct device *dev)
> +{
> +#ifdef CONFIG_ARM_DMA_USE_IOMMU
> +	struct dma_iommu_mapping *mapping = to_dma_iommu_mapping(dev);
> +	const struct dma_map_ops *dma_ops;
> +
> +	if (!mapping)
> +		return;
> +
> +	arm_iommu_release_mapping(mapping);
> +	arm_iommu_detach_device(dev);
> +
> +	dma_ops = arm_get_dma_map_ops(dev->archdata.dma_coherent);
> +	set_dma_ops(dev, dma_ops);

Why not simply:

	set_dma_ops(dev, arm_get_dma_map_ops(dev->archdata.dma_coherent));