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Date:   Wed, 4 Jan 2023 09:17:33 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Lu Baolu <baolu.lu@linux.intel.com>
Cc:     Joerg Roedel <joro@8bytes.org>,
        Christoph Hellwig <hch@infradead.org>,
        Kevin Tian <kevin.tian@intel.com>,
        Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
        Hector Martin <marcan@marcan.st>,
        Sven Peter <sven@svenpeter.dev>,
        Rob Clark <robdclark@gmail.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Yong Wu <yong.wu@mediatek.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Heiko Stuebner <heiko@sntech.de>,
        Matthew Rosato <mjrosato@linux.ibm.com>,
        Orson Zhai <orsonzhai@gmail.com>,
        Baolin Wang <baolin.wang@linux.alibaba.com>,
        Chunyan Zhang <zhang.lyra@gmail.com>,
        Chen-Yu Tsai <wens@csie.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        iommu@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 10/19] iommu: Add set_platform_dma_ops iommu ops
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References: <20230104125725.271850-1-baolu.lu@linux.intel.com>
 <20230104125725.271850-11-baolu.lu@linux.intel.com>
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On Wed, Jan 04, 2023 at 08:57:16PM +0800, Lu Baolu wrote:

> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index de91dd88705b..4e35a9f94873 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -2163,6 +2163,17 @@ static int iommu_group_do_detach_device(struct device *dev, void *data)
>  	return 0;
>  }
>  
> +static int iommu_group_do_set_platform_dma(struct device *dev, void *data)
> +{
> +	const struct iommu_ops *ops = dev_iommu_ops(dev);
> +
> +	if (!ops->set_platform_dma_ops)
> +		return -EINVAL;
> +
> +	ops->set_platform_dma_ops(dev);
> +	return 0;
> +}
> +
>  static int __iommu_group_set_domain(struct iommu_group *group,
>  				    struct iommu_domain *new_domain)
>  {
> @@ -2177,10 +2188,14 @@ static int __iommu_group_set_domain(struct iommu_group *group,
>  	 * platform specific behavior.
>  	 */
>  	if (!new_domain) {
> -		if (WARN_ON(!group->domain->ops->detach_dev))
> -			return -EINVAL;

This should still have the WARN_ON..

if (WARN_ON(!group->domain->ops->detach_dev && !dev_iommu_ops(dev)->set_platform_dma_ops)

Jason