Catching up with these threads, so replying to a patch I already
applied.
On Tue, Mar 07, 2017 at 06:43:32PM +0100, Geert Uytterhoeven wrote:
> --- a/arch/arm64/mm/dma-mapping.c
> +++ b/arch/arm64/mm/dma-mapping.c
> @@ -584,20 +584,7 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size,
> */
> gfp |= __GFP_ZERO;
>
> - if (gfpflags_allow_blocking(gfp)) {
> - struct page **pages;
> - pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL, coherent);
> -
> - pages = iommu_dma_alloc(dev, iosize, gfp, attrs, ioprot,
> - handle, flush_page);
> - if (!pages)
> - return NULL;
> -
> - addr = dma_common_pages_remap(pages, size, VM_USERMAP, prot,
> - __builtin_return_address(0));
> - if (!addr)
> - iommu_dma_free(dev, pages, iosize, handle);
> - } else {
> + if (!gfpflags_allow_blocking(gfp)) {
> struct page *page;
> /*
> * In atomic context we can't remap anything, so we'll only
> @@ -621,6 +608,45 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size,
> __free_from_pool(addr, size);
> addr = NULL;
> }
> + } else if (attrs & DMA_ATTR_FORCE_CONTIGUOUS) {
> + pgprot_t prot = __get_dma_pgprot(attrs, PAGE_KERNEL, coherent);
> + struct page *page;
> +
> + page = dma_alloc_from_contiguous(dev, size >> PAGE_SHIFT,
> + get_order(size), gfp);
> + if (!page)
> + return NULL;
> +
> + *handle = iommu_dma_map_page(dev, page, 0, iosize, ioprot);
> + if (iommu_dma_mapping_error(dev, *handle)) {
> + dma_release_from_contiguous(dev, page,
> + size >> PAGE_SHIFT);
> + return NULL;
> + }
> + if (!coherent)
> + __dma_flush_area(page_to_virt(page), iosize);
> +
> + addr = dma_common_contiguous_remap(page, size, VM_USERMAP,
> + prot,
> + __builtin_return_address(0));
Do we need to call dma_common_pages_remap() if the allocation is
coherent? In the __dma_alloc() case we don't do it but simply use
page_address(page) as returned by __dma_alloc_coherent().
(note that my comment is not meant to fix the issue reported by Andrzej
Hajda but I just spotted it)
--
Catalin
