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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 <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2015-03-10 16:41:35 +00:00
parent c517d838eb
commit 8bf1268f48
1 changed files with 1 additions and 1 deletions
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2
arch/arm/mm/dma-mapping.c
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@ -171,7 +171,7 @@ static int __dma_supported(struct device *dev, u64 mask, bool warn)
*/ */
if (sizeof(mask) != sizeof(dma_addr_t) && if (sizeof(mask) != sizeof(dma_addr_t) &&
mask > (dma_addr_t)~0 && mask > (dma_addr_t)~0 &&
dma_to_pfn(dev, ~0) < max_pfn) { dma_to_pfn(dev, ~0) < max_pfn - 1) {
if (warn) { if (warn) {
dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n", dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n",
mask); mask);