[PATCH] [29/50] mm/nommu.c: fix remap_pfn_range()

[Andi Kleen]

2.6.35-longterm review patch.  If anyone has any objections, please let me know.

------------------
From: Bob Liu <lliubbo@xxxxxxxxx>

[ upstream commit 8f3b1327aa454bc8283e96bca7669c3c88b83f79 ]

remap_pfn_range() means map physical address pfn<<PAGE_SHIFT to user addr.

For nommu arch it's implemented by vma->vm_start = pfn << PAGE_SHIFT which
is wrong acroding the original meaning of this function.  And some driver
developer using remap_pfn_range() with correct parameter will get
unexpected result because vm_start is changed.  It should be implementd
like addr = pfn << PAGE_SHIFT but which is meanless on nommu arch, this
patch just make it simply return.

Parameter name and setting of vma->vm_flags also be fixed.

Signed-off-by: Bob Liu <lliubbo@xxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Acked-by: Greg Ungerer <gerg@xxxxxxxxxxx>
Cc: Mike Frysinger <vapier@xxxxxxxxxx>
Cc: Bob Liu <lliubbo@xxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Index: linux-2.6.35.y/mm/nommu.c
===================================================================
--- linux-2.6.35.y.orig/mm/nommu.c
+++ linux-2.6.35.y/mm/nommu.c
@@ -1747,10 +1747,13 @@ struct page *follow_page(struct vm_area_
 	return NULL;
 }
 
-int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
-		unsigned long to, unsigned long size, pgprot_t prot)
+int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
+		unsigned long pfn, unsigned long size, pgprot_t prot)
 {
-	vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
+	if (addr != (pfn << PAGE_SHIFT))
+		return -EINVAL;
+
+	vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
 	return 0;
 }
 EXPORT_SYMBOL(remap_pfn_range);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/