diff options
authorFranck Bui-Huu <fbuihuu@gmail.com>2006-10-12 21:06:33 +0200
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-13 08:35:38 -0700
commit99a10a60ba9bedcf5d70ef81414d3e03816afa3f (patch)
parenta5344a9555fffd045218aced89afd6ca0f884e10 (diff)
[PATCH] Fix up mmap_kmem
vma->vm_pgoff is an pfn _offset_ relatif to the begining of the memory start. The previous code was doing at first: vma->vm_pgoff << PAGE_SHIFT which results into a wrong physical address since some platforms have a physical mem start that can be different from 0. After that the previous call __pa() on this wrong physical address, however __pa() is used to convert a _virtual_ address into a physical one. This patch rewrites this convertion. It calculates the pfn of PAGE_OFFSET which is the pfn of the mem start then it adds the vma->vm_pgoff to it. It also uses virt_to_phys() instead of __pa() since the latter shouldn't be used by drivers. Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 6511012cbdcd..a89cb52228c2 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -292,8 +292,8 @@ 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