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>
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@ -1813,10 +1813,13 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
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return NULL;
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}
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int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
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unsigned long to, unsigned long size, pgprot_t prot)
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int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
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unsigned long pfn, unsigned long size, pgprot_t prot)
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{
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vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
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if (addr != (pfn << PAGE_SHIFT))
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return -EINVAL;
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vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
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return 0;
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}
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EXPORT_SYMBOL(remap_pfn_range);
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