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authorChristoph Hellwig <hch@lst.de>2019-07-26 10:26:40 +0300
committerChristoph Hellwig <hch@lst.de>2019-08-10 20:52:45 +0300
commit33dcb37cef741294b481f4d889a465b8091f11bf (patch)
tree129f9cde5b52cd77e04382c99ff0421aa862354b /arch/arm
parentd8ad55538abe443919e20e0bb996561bca9cad84 (diff)
downloadlinux-33dcb37cef741294b481f4d889a465b8091f11bf.tar.xz
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 <shawn@anastas.io> Reported-by: Gavin Li <git@thegavinli.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Catalin Marinas <catalin.marinas@arm.com> # arm64
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/mm/dma-mapping.c4
1 files changed, 1 insertions, 3 deletions
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,