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Commit 8f3b1327 authored by Bob Liu's avatar Bob Liu Committed by Linus Torvalds
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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: default avatarBob Liu <lliubbo@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: David Howells <dhowells@redhat.com>
Acked-by: default avatarGreg Ungerer <gerg@uclinux.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus 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);