From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stefano Stabellini , Catalin Marinas , Konrad Rzeszutek Wilk Subject: [PATCH 3.18 012/150] swiotlb-xen: remove BUG_ON in xen_bus_to_phys Date: Tue, 13 Jan 2015 23:21:23 -0800 Message-Id: <20150114072056.422114928@linuxfoundation.org> In-Reply-To: <20150114072055.842408181@linuxfoundation.org> References: <20150114072055.842408181@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stefano Stabellini commit c884227eaae9936f8ecbde6e1387bccdab5f4e90 upstream. 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 Reviewed-by: Catalin Marinas Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman --- drivers/xen/swiotlb-xen.c | 2 -- 1 file changed, 2 deletions(-) --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -96,8 +96,6 @@ static inline phys_addr_t xen_bus_to_phy 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;