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swiotlb-xen: remove BUG_ON in xen_bus_to_phys 

On x86 truncation cannot occur because config XEN depends on X86_64 ||
(X86_32 && X86_PAE).

On ARM truncation can occur without CONFIG_ARM_LPAE, when the dma
operation involves foreign grants. However in that case the physical
address returned by xen_bus_to_phys is actually invalid (there is no mfn
to pfn tracking for foreign grants on ARM) and it is not used.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: stable@vger.kernel.org
This commit is contained in:
Stefano Stabellini 2014-11-21 11:10:39 +00:00 committed by David Vrabel
parent d6883e6f32
commit c884227eaa
1 changed files with 0 additions and 2 deletions
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2
drivers/xen/swiotlb-xen.c
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@ -96,8 +96,6 @@ static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr)
dma_addr_t dma = (dma_addr_t)pfn << PAGE_SHIFT;
phys_addr_t paddr = dma;
BUG_ON(paddr != dma); /* truncation has occurred, should never happen */
paddr |= baddr & ~PAGE_MASK;
return paddr;