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authorFranck Bui-Huu <fbuihuu@gmail.com>2006-10-12 15:06:33 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-13 11:35:38 -0400
commit99a10a60ba9bedcf5d70ef81414d3e03816afa3f (patch)
tree7ea2c86ddd2bfdab885fe86f1c60d412e5730bb1 /drivers/char/mem.c
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>
Diffstat (limited to 'drivers/char/mem.c')
-rw-r--r--drivers/char/mem.c4
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)
292{ 292{
293 unsigned long pfn; 293 unsigned long pfn;
294 294
295 /* Turn a kernel-virtual address into a physical page frame */ 295 /* Turn a pfn offset into an absolute pfn */
296 pfn = __pa((u64)vma->vm_pgoff << PAGE_SHIFT) >> PAGE_SHIFT; 296 pfn = PFN_DOWN(virt_to_phys((void *)PAGE_OFFSET)) + vma->vm_pgoff;
297 297
298 /* 298 /*
299 * RED-PEN: on some architectures there is more mapped memory 299 * RED-PEN: on some architectures there is more mapped memory