linux-kernel - Re: [PATCH 5/9] dma-mapping: support highmem in the generic remap allocator

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Date:   Tue, 4 Dec 2018 15:23:04 +0100
From:   Christoph Hellwig <hch@....de>
To:     Marek Szyprowski <m.szyprowski@...sung.com>
Cc:     Robin Murphy <robin.murphy@....com>,
        Christoph Hellwig <hch@....de>,
        iommu@...ts.linux-foundation.org,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        linux-kernel@...r.kernel.org, Guo Ren <ren_guo@...ky.com>,
        Laura Abbott <labbott@...hat.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 5/9] dma-mapping: support highmem in the generic remap
 allocator

On Tue, Dec 04, 2018 at 09:38:02AM +0100, Marek Szyprowski wrote:
> Hi All,
> 
> On 2018-11-30 20:05, Robin Murphy wrote:
> > On 05/11/2018 12:19, Christoph Hellwig wrote:
> >> By using __dma_direct_alloc_pages we can deal entirely with struct page
> >> instead of having to derive a kernel virtual address.
> >
> > Simple enough :)
> >
> > Reviewed-by: Robin Murphy <robin.murphy@....com>
> 
> This patch has landed linux-next yesterday and I've noticed that it
> breaks operation of many drivers. The change looked simple, but a stupid
> bug managed to slip into the code. After a short investigation I've
> noticed that __dma_direct_alloc_pages() doesn't set dma_handle and zero
> allocated memory, while dma_direct_alloc_pages() did. The other
> difference is the lack of set_memory_decrypted() handling.
> 
> Following patch fixes the issue, but maybe it would be better to fix it
> in kernel/dma/direct.c:

Thanks for spotting this Marek.  Can you send the patch below with a
signoff and a changelog so that I can queue it up?