Commit 8f3b1327 authored Jul 08, 2011 by Bob Liu Committed by Linus Torvalds Jul 08, 2011

mm/nommu.c: fix remap_pfn_range()



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@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent f607e7fc

mm/nommu.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -1813,10 +1813,13 @@ struct page follow_page(struct vm_area_struct vma, unsigned long address,
		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);

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