1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 4f1813e04754..f5c160caf9f4 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -293,8 +293,8 @@ static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
 {
         unsigned long pfn;
 
-        /* Turn a pfn offset into an absolute pfn */
-        pfn = PFN_DOWN(virt_to_phys((void *)PAGE_OFFSET)) + vma->vm_pgoff;
+        /* Turn a kernel-virtual address into a physical page frame */
+        pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
 
         /*
          * RED-PEN: on some architectures there is more mapped memory