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Date:   Tue, 1 Dec 2020 15:49:16 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Ricardo Ribalda <ribalda@chromium.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        IOMMU DRIVERS <iommu@lists.linux-foundation.org>,
        Joerg Roedel <joro@8bytes.org>,
        Linux Doc Mailing List <linux-doc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        Tomasz Figa <tfiga@chromium.org>,
        Sergey Senozhatsky <senozhatsky@google.com>
Subject: Re: [PATCH v3 5/6] media: uvcvideo: Use dma_alloc_noncontiguos API
Message-ID: <20201201144916.GA14682@lst.de>
References: <20201125221917.150463-1-ribalda@chromium.org> <20201130083410.GD32234@lst.de> <20201201033658.GE3723071@google.com>
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On Tue, Dec 01, 2020 at 12:36:58PM +0900, Sergey Senozhatsky wrote:
> Not that I have any sound experience in this area, but the helper
> probably won't hurt. Do you also plan to add vmap() to that helper
> or dma_alloc_noncontiguous()/sg_alloc_table_from_pages() only?

Yes, I think adding the vmap is useful, and it probably makes sense
to do that unconditionally.  I'd also include the fallback to
dma_alloc_pages when the noncontig version isn't supported in the
helper.