[PATCH] x86_64: Fix off by one in IOMMU check
Fix off by one when checking if the machine has enougn memory to need IOMMU
This caused the IOMMUs to be needlessly enabled for mem=4G
Based on a patch from Jon Mason
Signed-off-by: jdmason@us.ibm.com
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 1faae5f..5337ca0 100644
--- a/arch/x86_64/mm/init.c
+++ b/arch/x86_64/mm/init.c
@@ -424,7 +424,7 @@
#ifdef CONFIG_SWIOTLB
if (!iommu_aperture &&
- (end_pfn >= 0xffffffff>>PAGE_SHIFT || force_iommu))
+ ((end_pfn-1) >= 0xffffffff>>PAGE_SHIFT || force_iommu))
swiotlb = 1;
if (swiotlb)
swiotlb_init();