From b18814e767a445534ab9ccba02e82a31208f85d6 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sun, 4 Nov 2018 17:27:56 +0100 Subject: [PATCH] dma-direct: provide page based alloc/free helpers Some architectures support remapping highmem into DMA coherent allocations. To use the common code for them we need variants of dma_direct_{alloc,free}_pages that do not use kernel virtual addresses. Signed-off-by: Christoph Hellwig Reviewed-by: Robin Murphy --- include/linux/dma-direct.h | 3 +++ kernel/dma/direct.c | 32 ++++++++++++++++++++++---------- 2 files changed, 25 insertions(+), 10 deletions(-) diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index 9e66bfe369aa..61b78f934f64 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -67,6 +67,9 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs); void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs); +struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs); +void __dma_direct_free_pages(struct device *dev, size_t size, struct page *page); dma_addr_t dma_direct_map_page(struct device *dev, struct page *page, unsigned long offset, size_t size, enum dma_data_direction dir, unsigned long attrs); diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 22a12ab5a5e9..680287779b0a 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -103,14 +103,13 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) min_not_zero(dev->coherent_dma_mask, dev->bus_dma_mask); } -void *dma_direct_alloc_pages(struct device *dev, size_t size, +struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) { unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; int page_order = get_order(size); struct page *page = NULL; u64 phys_mask; - void *ret; if (attrs & DMA_ATTR_NO_WARN) gfp |= __GFP_NOWARN; @@ -150,11 +149,22 @@ again: } } + return page; +} + +void *dma_direct_alloc_pages(struct device *dev, size_t size, + dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs) +{ + struct page *page; + void *ret; + + page = __dma_direct_alloc_pages(dev, size, dma_handle, gfp, attrs); if (!page) return NULL; + ret = page_address(page); if (force_dma_unencrypted()) { - set_memory_decrypted((unsigned long)ret, 1 << page_order); + set_memory_decrypted((unsigned long)ret, 1 << get_order(size)); *dma_handle = __phys_to_dma(dev, page_to_phys(page)); } else { *dma_handle = phys_to_dma(dev, page_to_phys(page)); @@ -163,20 +173,22 @@ again: return ret; } -/* - * NOTE: this function must never look at the dma_addr argument, because we want - * to be able to use it as a helper for iommu implementations as well. - */ +void __dma_direct_free_pages(struct device *dev, size_t size, struct page *page) +{ + unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; + + if (!dma_release_from_contiguous(dev, page, count)) + __free_pages(page, get_order(size)); +} + void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr, dma_addr_t dma_addr, unsigned long attrs) { - unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT; unsigned int page_order = get_order(size); if (force_dma_unencrypted()) set_memory_encrypted((unsigned long)cpu_addr, 1 << page_order); - if (!dma_release_from_contiguous(dev, virt_to_page(cpu_addr), count)) - free_pages((unsigned long)cpu_addr, page_order); + __dma_direct_free_pages(dev, size, virt_to_page(cpu_addr)); } void *dma_direct_alloc(struct device *dev, size_t size, -- 2.30.2