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Date:   Tue, 31 Aug 2021 16:17:47 +0100
From:   Will Deacon <will@kernel.org>
To:     Claire Chang <tientzu@chromium.org>
Cc:     hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com,
        konrad.wilk@oracle.com, iommu@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, linux@roeck-us.net
Subject: Re: [PATCH] swiotlb: use depends on for DMA_RESTRICTED_POOL
Message-ID: <20210831151746.GB32001@willie-the-truck>
References: <20210827034802.1065294-1-tientzu@chromium.org>
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On Fri, Aug 27, 2021 at 11:48:02AM +0800, Claire Chang wrote:
> Use depends on instead of select for DMA_RESTRICTED_POOL; otherwise it
> will make SWIOTLB user configurable and cause compile errors for some
> arch (e.g. mips).
> 
> Fixes: 0b84e4f8b793 ("swiotlb: Add restricted DMA pool initialization")
> Reported-by: Guenter Roeck <linux@roeck-us.net>
> Signed-off-by: Claire Chang <tientzu@chromium.org>
> ---
>  kernel/dma/Kconfig | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig
> index fd4db714d86b..1b02179758cb 100644
> --- a/kernel/dma/Kconfig
> +++ b/kernel/dma/Kconfig
> @@ -82,8 +82,7 @@ config SWIOTLB
>  
>  config DMA_RESTRICTED_POOL
>  	bool "DMA Restricted Pool"
> -	depends on OF && OF_RESERVED_MEM
> -	select SWIOTLB
> +	depends on OF && OF_RESERVED_MEM && SWIOTLB
>  	help
>  	  This enables support for restricted DMA pools which provide a level of
>  	  DMA memory protection on systems with limited hardware protection

Acked-by: Will Deacon <will@kernel.org>

Will