Messages in this thread Patch in this message | | | From | Yong Wu <> | Subject | [PATCH v2 1/2] dma/iommu: Add pgsize_bitmap confirmation in __iommu_dma_alloc_pages | Date | Mon, 28 Mar 2016 14:32:11 +0800 |
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Currently __iommu_dma_alloc_pages assumes that all the IOMMU support the granule of PAGE_SIZE. It call alloc_page to try allocating memory in the last time. Fortunately the mininum pagesize in all the current IOMMU is SZ_4K, so this works well.
But there may be a case in which the mininum granule of IOMMU may be larger than PAGE_SIZE, then it will abort as the IOMMU cann't map the discontinuous memory within a granule. For example, the pgsize_bitmap of the IOMMU only has SZ_16K while the PAGE_SIZE is SZ_4K, then we have to prepare SZ_16K continuous memory at least for each a granule iommu mapping.
Signed-off-by: Yong Wu <yong.wu@mediatek.com>
--- v2: -rebase on v4.6-rc1. -add a new patch([1/2] add pgsize_bitmap) here.
drivers/iommu/dma-iommu.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 72d6182..75ce71e 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -190,11 +190,13 @@ static void __iommu_dma_free_pages(struct page **pages, int count) kvfree(pages); } -static struct page **__iommu_dma_alloc_pages(unsigned int count, gfp_t gfp) +static struct page **__iommu_dma_alloc_pages(unsigned int count, gfp_t gfp, + unsigned long pgsize_bitmap) { struct page **pages; unsigned int i = 0, array_size = count * sizeof(*pages); - unsigned int order = MAX_ORDER; + int min_order = get_order(1 << __ffs(pgsize_bitmap)); + int order = MAX_ORDER; if (array_size <= PAGE_SIZE) pages = kzalloc(array_size, GFP_KERNEL); @@ -213,13 +215,16 @@ static struct page **__iommu_dma_alloc_pages(unsigned int count, gfp_t gfp) /* * Higher-order allocations are a convenience rather * than a necessity, hence using __GFP_NORETRY until - * falling back to single-page allocations. + * falling back to min size allocations. */ - for (order = min_t(unsigned int, order, __fls(count)); - order > 0; order--) { - page = alloc_pages(gfp | __GFP_NORETRY, order); + for (order = min_t(int, order, __fls(count)); + order >= min_order; order--) { + page = alloc_pages((order == min_order) ? gfp : + gfp | __GFP_NORETRY, order); if (!page) continue; + if (!order) + break; if (PageCompound(page)) { if (!split_huge_page(page)) break; @@ -229,8 +234,6 @@ static struct page **__iommu_dma_alloc_pages(unsigned int count, gfp_t gfp) break; } } - if (!page) - page = alloc_page(gfp); if (!page) { __iommu_dma_free_pages(pages, i); return NULL; @@ -292,7 +295,8 @@ struct page **iommu_dma_alloc(struct device *dev, size_t size, *handle = DMA_ERROR_CODE; - pages = __iommu_dma_alloc_pages(count, gfp); + pages = __iommu_dma_alloc_pages(count, gfp, + domain->ops->pgsize_bitmap); if (!pages) return NULL; -- 1.8.1.1.dirty
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