From: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
To: Max Filippov <jcmvbkbc-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: Chris Zankel <chris-YvXeqwSYzG2sTnJN9+BGXg@public.gmane.org>,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>,
linux-xtensa-PjhNF2WwrV/0Sa2dR60CXw@public.gmane.org
Subject: Re: [PATCH 1/3] xtensa: remove partial support for DMA buffers in high memory
Date: Thu, 20 Sep 2018 20:08:33 +0200 [thread overview]
Message-ID: <20180920180833.GB27677@lst.de> (raw)
In-Reply-To: <CAMo8BfKyW+3t+L+oQ+nDyEs8KcASPC8CeUP3QPoANQC=XKP9hg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
On Thu, Sep 20, 2018 at 10:44:55AM -0700, Max Filippov wrote:
> Hi Christoph,
>
> On Thu, Sep 20, 2018 at 10:15 AM, Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org> wrote:
> > This reverts commit 6137e4166004e2ec383ac05d5ca15831f4668806.
> >
> > We explicitly clear GFP_HIGHMEM from the allowed dma flags at the beginning
> > of the function (and the generic dma_alloc_attr function calling us does the
> > same!), so this code just adds dead wood.
>
> No, not really: dma_alloc_from_contiguous does not accept flags (only
> no_warn bit)
> and may return arbitrary pages. That's the case that this code is handling.
dma_alloc_from_contiguous calls cma_alloc to do the actual
allocation, and that uses alloc_contig_range with the GFP_KERNEL
flag. How do you end up getting highmem patches from it?
next prev parent reply other threads:[~2018-09-20 18:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-20 17:15 xtensa dma-mapping tidyups Christoph Hellwig
[not found] ` <20180920171540.2657-1-hch-jcswGhMUV9g@public.gmane.org>
2018-09-20 17:15 ` [PATCH 1/3] xtensa: remove partial support for DMA buffers in high memory Christoph Hellwig
[not found] ` <20180920171540.2657-2-hch-jcswGhMUV9g@public.gmane.org>
2018-09-20 17:44 ` Max Filippov
[not found] ` <CAMo8BfKyW+3t+L+oQ+nDyEs8KcASPC8CeUP3QPoANQC=XKP9hg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-09-20 18:08 ` Christoph Hellwig [this message]
[not found] ` <20180920180833.GB27677-jcswGhMUV9g@public.gmane.org>
2018-09-20 19:08 ` Max Filippov
[not found] ` <20180921065100.GA14246@lst.de>
[not found] ` <20180921065100.GA14246-jcswGhMUV9g@public.gmane.org>
2018-09-21 16:40 ` Michał Nazarewicz
2018-09-21 17:42 ` Max Filippov
2018-09-20 17:15 ` [PATCH 2/3] xtensa: remove ZONE_DMA Christoph Hellwig
2018-09-20 17:15 ` [PATCH 3/3] xtensa: use dma_direct_{alloc,free}_pages Christoph Hellwig
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