From 8bf1268f48ad9bf5d6401b4db913e6d85b0863f6 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 10 Mar 2015 16:41:35 +0000 Subject: [PATCH] ARM: dma-api: fix off-by-one error in __dma_supported() When validating the mask against the amount of memory we have available (so that we can trap 32-bit DMA addresses with >32-bits memory), we had not taken account of the fact that max_pfn is the maximum PFN number plus one that would be in the system. There are several references in the code which bear this out: mm/page_owner.c: for (; pfn < max_pfn; pfn++) { } arch/x86/kernel/setup.c: high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) Signed-off-by: Russell King --- arch/arm/mm/dma-mapping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 170a116d1b29..c27447653903 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -171,7 +171,7 @@ static int __dma_supported(struct device *dev, u64 mask, bool warn) */ if (sizeof(mask) != sizeof(dma_addr_t) && mask > (dma_addr_t)~0 && - dma_to_pfn(dev, ~0) < max_pfn) { + dma_to_pfn(dev, ~0) < max_pfn - 1) { if (warn) { dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n", mask); -- 2.20.1