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Subject: Re: [PATCH 2/2] swiotlb-xen: override common mmap and get_sgtable dma
 ops
To:     Christoph Hellwig <hch@lst.de>
Cc:     Roman Skakun <rm.skakun@gmail.com>,
        Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
        Juergen Gross <jgross@suse.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        xen-devel@lists.xenproject.org, iommu@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org,
        Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>,
        Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>,
        Volodymyr Babchuk <volodymyr_babchuk@epam.com>,
        Roman Skakun <roman_skakun@epam.com>,
        Andrii Anisov <andrii_anisov@epam.com>
References: <855a58e2-1e03-4763-cb56-81367b73762c@oracle.com>
 <20210616114205.38902-1-roman_skakun@epam.com>
 <20210616114205.38902-2-roman_skakun@epam.com>
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 <20210616142148.GA764@lst.de>
From:   Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Date:   Wed, 16 Jun 2021 11:33:50 -0400
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On 6/16/21 10:21 AM, Christoph Hellwig wrote:
> On Wed, Jun 16, 2021 at 10:12:55AM -0400, Boris Ostrovsky wrote:
>> I wonder now whether we could avoid code duplication between here and dma_common_mmap()/dma_common_get_sgtable() and use your helper there.
>>
>>
>> Christoph, would that work?  I.e. something like
> You should not duplicate the code at all, and just make the common
> helpers work with vmalloc addresses.


Isn't the expectation of virt_to_page() that it only works on non-vmalloc'd addresses? (This is not a rhetorical question, I actually don't know).


-boris