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path: root/drivers/char/mem.c
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Diffstat (limited to 'drivers/char/mem.c')
-rw-r--r--drivers/char/mem.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 6511012cbdcd..55473371b7c6 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -26,6 +26,7 @@
#include <linux/backing-dev.h>
#include <linux/bootmem.h>
#include <linux/pipe_fs_i.h>
+#include <linux/pfn.h>
#include <asm/uaccess.h>
#include <asm/io.h>
@@ -292,8 +293,8 @@ static int mmap_kmem(struct file * file, struct vm_area_struct * vma)
{
unsigned long pfn;
- /* Turn a kernel-virtual address into a physical page frame */
- pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT;
+ /* Turn a pfn offset into an absolute pfn */
+ pfn = PFN_DOWN(virt_to_phys((void *)PAGE_OFFSET)) + vma->vm_pgoff;
/*
* RED-PEN: on some architectures there is more mapped memory