generic, x86: fix add iommu_num_pages helper function

This IOMMU helper function doesn't work for some architectures:

  http://marc.info/?l=linux-kernel&m=121699304403202&w=2

It also breaks POWER and SPARC builds:

  http://marc.info/?l=linux-kernel&m=121730388001890&w=2

Currently, only x86 IOMMUs use this so let's move it to x86 for
now.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 8dbffb846de9..87d4d6964ec2 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -123,6 +123,14 @@ void __init pci_iommu_alloc(void)
 
         pci_swiotlb_init();
 }
+
+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);
 #endif
 
 /*