Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH 1/2] iommu/dma: Respect __GFP_DMA and __GFP_DMA32 in incoming GFP flags | From | Robin Murphy <> | Date | Tue, 27 Jun 2017 12:01:21 +0100 |
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On 27/06/17 08:28, Tomasz Figa wrote: > Current implementation of __iommu_dma_alloc_pages() keeps adding > __GFP_HIGHMEM to GFP flags regardless of whether other zone flags are > already included in the incoming flags. If __GFP_DMA or __GFP_DMA32 is > set at the same time as __GFP_HIGHMEM, the allocation fails due to > invalid zone flag combination. > > Fix this by checking for __GFP_DMA and __GFP_DMA32 in incoming GFP flags > and adding __GFP_HIGHMEM only if they are not present.
Wouldn't it make more sense to strip off the ZONE_DMA* related flags, since the whole point here is that we don't care where the pages come from?
Robin.
> Signed-off-by: Tomasz Figa <tfiga@chromium.org> > --- > drivers/iommu/dma-iommu.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index 9d1cebe7f6cb..29965a092a69 100644 > --- a/drivers/iommu/dma-iommu.c > +++ b/drivers/iommu/dma-iommu.c > @@ -445,8 +445,14 @@ static struct page **__iommu_dma_alloc_pages(unsigned int count, > if (!pages) > return NULL; > > - /* IOMMU can map any pages, so himem can also be used here */ > - gfp |= __GFP_NOWARN | __GFP_HIGHMEM; > + /* > + * IOMMU can map any pages, so himem can also be used here, > + * unless another DMA zone is explicitly requested. > + */ > + if (!(gfp & (__GFP_DMA | __GFP_DMA32))) > + gfp |= __GFP_HIGHMEM; > + > + gfp |= __GFP_NOWARN; > > while (count) { > struct page *page = NULL; >
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