From 3bc9f79ee1ddc913be0a6d3592036683ef8a3148 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Fri, 25 Jul 2008 14:57:58 +0200 Subject: [PATCH] iommu: add iommu_num_pages helper function Calculating the number of pages from given address and length numbers is a task required in multiple IOMMU implementations. So implement this as a generic function into the IOMMU helper code. Signed-off-by: Joerg Roedel Cc: iommu@lists.linux-foundation.org Cc: bhavna.sarathy@amd.com Cc: robert.richter@amd.com Cc: FUJITA Tomonori Signed-off-by: Ingo Molnar --- include/linux/iommu-helper.h | 1 + lib/iommu-helper.c | 8 ++++++++ 2 files changed, 9 insertions(+) diff --git a/include/linux/iommu-helper.h b/include/linux/iommu-helper.h index c975caf75385..f8598f583944 100644 --- a/include/linux/iommu-helper.h +++ b/include/linux/iommu-helper.h @@ -8,3 +8,4 @@ extern unsigned long iommu_area_alloc(unsigned long *map, unsigned long size, unsigned long align_mask); extern void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr); +extern unsigned long iommu_num_pages(unsigned long addr, unsigned long len); diff --git a/lib/iommu-helper.c b/lib/iommu-helper.c index a3b8d4c3f77a..889ddce2021e 100644 --- a/lib/iommu-helper.c +++ b/lib/iommu-helper.c @@ -80,3 +80,11 @@ void iommu_area_free(unsigned long *map, unsigned long start, unsigned int nr) } } EXPORT_SYMBOL(iommu_area_free); + +unsigned long iommu_num_pages(unsigned long addr, unsigned long len) +{ + unsigned long size = roundup((addr & ~PAGE_MASK) + len, PAGE_SIZE); + + return size >> PAGE_SHIFT; +} +EXPORT_SYMBOL(iommu_num_pages);