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Date:   Tue, 1 Sep 2020 15:53:04 +0200
From:   Thomas Bogendoerfer <tsbogend@alpha.franken.de>
To:     Christoph Hellwig <hch@lst.de>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
        Joonyoung Shim <jy0922.shim@samsung.com>,
        Seung-Woo Kim <sw0312.kim@samsung.com>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Ben Skeggs <bskeggs@redhat.com>,
        Pawel Osciak <pawel@osciak.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Matt Porter <mporter@kernel.crashing.org>,
        iommu@lists.linux-foundation.org,
        Tom Lendacky <thomas.lendacky@amd.com>,
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Subject: Re: [PATCH 08/28] MIPS: make dma_sync_*_for_cpu a little less
 overzealous
Message-ID: <20200901135304.GC11944@alpha.franken.de>
References: <20200819065555.1802761-1-hch@lst.de>
 <20200819065555.1802761-9-hch@lst.de>
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On Wed, Aug 19, 2020 at 08:55:35AM +0200, Christoph Hellwig wrote:
> When transferring DMA ownership back to the CPU there should never
> be any writeback from the cache, as the buffer was owned by the
> device until now.  Instead it should just be invalidated for the
> mapping directions where the device could have written data.
> Note that the changes rely on the fact that kmap_atomic is stubbed
> out for the !HIGHMEM case to simplify the code a bit.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  arch/mips/mm/dma-noncoherent.c | 44 +++++++++++++++++++++-------------
>  1 file changed, 28 insertions(+), 16 deletions(-)

Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]