From 33dcb37cef741294b481f4d889a465b8091f11bf Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 26 Jul 2019 09:26:40 +0200 Subject: dma-mapping: fix page attributes for dma_mmap_* All the way back to introducing dma_common_mmap we've defaulted to mark the pages as uncached. But this is wrong for DMA coherent devices. Later on DMA_ATTR_WRITE_COMBINE also got incorrect treatment as that flag is only treated special on the alloc side for non-coherent devices. Introduce a new dma_pgprot helper that deals with the check for coherent devices so that only the remapping cases ever reach arch_dma_mmap_pgprot and we thus ensure no aliasing of page attributes happens, which makes the powerpc version of arch_dma_mmap_pgprot obsolete and simplifies the remaining ones. Note that this means arch_dma_mmap_pgprot is a bit misnamed now, but we'll phase it out soon. Fixes: 64ccc9c033c6 ("common: dma-mapping: add support for generic dma_mmap_* calls") Reported-by: Shawn Anastasio Reported-by: Gavin Li Signed-off-by: Christoph Hellwig Acked-by: Catalin Marinas # arm64 --- arch/arm/mm/dma-mapping.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'arch/arm') diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 6774b03aa405..d42557ee69c2 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -2405,9 +2405,7 @@ long arch_dma_coherent_to_pfn(struct device *dev, void *cpu_addr, pgprot_t arch_dma_mmap_pgprot(struct device *dev, pgprot_t prot, unsigned long attrs) { - if (!dev_is_dma_coherent(dev)) - return __get_dma_pgprot(attrs, prot); - return prot; + return __get_dma_pgprot(attrs, prot); } void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, -- cgit v1.2.3