Messages in this thread Patch in this message | | | Subject | Re: [PATCH 12/21] dma-iommu: factor atomic pool allocations into helpers | From | Robin Murphy <> | Date | Tue, 23 Apr 2019 11:01:44 +0100 |
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On 19/04/2019 09:23, Christoph Hellwig wrote: > On Thu, Apr 18, 2019 at 07:15:00PM +0100, Robin Murphy wrote: >> Still, I've worked in the vm_map_pages() stuff pending in MM and given them >> the same treatment to finish the picture. Both x86_64_defconfig and >> i386_defconfig do indeed compile and link fine as I expected, so I really >> would like to understand the concern around #ifdefs better. > > This looks generally fine to me. One thing I'd like to do is to > generally make use of the fact that __iommu_dma_get_pages returns NULL > for the force contigous case as that cleans up a few things. Also > for the !DMA_REMAP case we need to try the page allocator when > dma_alloc_from_contiguous does not return a page. What do you thing > of the following incremental diff? If that is fine with you I can > fold that in and add back in the remaining patches from my series > not obsoleted by your patches and resend.
Wouldn't this suffice? Since we also use alloc_pages() in the coherent atomic case, the free path should already be able to deal with it.
Let me take a proper look at v3 and see how it all looks in context.
Robin.
----->8----- diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 1bc8d1de1a1d..0a02ddc27862 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -944,6 +944,8 @@ static void *iommu_dma_alloc(struct device *dev, size_t size, (attrs & DMA_ATTR_FORCE_CONTIGUOUS)) { page = dma_alloc_from_contiguous(dev, count, page_order, gfp & __GFP_NOWARN); + if (!page) + page = alloc_pages(gfp, page_order); } else { return iommu_dma_alloc_remap(dev, size, handle, gfp, attrs); }
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