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Date:   Thu, 22 Nov 2018 17:14:47 +0000
From:   Russell King - ARM Linux <linux@armlinux.org.uk>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Christoph Hellwig <hch@lst.de>, linux-arch@vger.kernel.org,
        linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org,
        linux-parisc@vger.kernel.org,
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        the arch/x86 maintainers <x86@kernel.org>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        iommu@lists.linux-foundation.org, jdmason@kudzu.us,
        xen-devel@lists.xenproject.org, robin.murphy@arm.com,
        linux-arm-kernel@lists.infradead.org, m.szyprowski@samsung.com
Subject: Re: remove the ->mapping_error method from dma_map_ops V2
Message-ID: <20181122171446.GJ30658@n2100.armlinux.org.uk>
References: <20181122140320.24080-1-hch@lst.de>
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On Thu, Nov 22, 2018 at 09:09:47AM -0800, Linus Torvalds wrote:
> On Thu, Nov 22, 2018 at 9:07 AM Russell King - ARM Linux
> <linux@armlinux.org.uk> wrote:
> >
> > I'm afraid that won't work very well - 32 bit platforms with 64-bit
> > addresses (LPAE) would have dma_addr_t as a 64-bit value, which
> > wouldn't fit into an unsigned long.
> 
> Good point. So we'd have to have a special IS_DMA_ERR() function that
> takes a dma_addr_t and checks the same "is it the top 4095 values".

No problem with that.

-- 
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