Commit ed5297a9 authored Nov 21, 2005 by Hugh Dickins Committed by Linus Torvalds Nov 22, 2005

[PATCH] unpaged: get_user_pages VM_RESERVED

The PageReserved removal in 2.6.15-rc1 prohibited get_user_pages on the areas
flagged VM_RESERVED in place of PageReserved. That is correct in theory - we
ought not to interfere with struct pages in such a reserved area; but in
practice it broke BTTV for one.

So revert to prohibiting only on VM_IO: if someone gets into trouble with
get_user_pages on VM_RESERVED, it'll just be a "don't do that".

You can argue that videobuf_mmap_mapper shouldn't set VM_RESERVED in the first
place, but now's not the time for breaking drivers without notice.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent aa1a64ee

mm/memory.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -968,7 +968,7 @@ int get_user_pages(struct task_struct tsk, struct mm_struct mm,
		continue;
		}

		if (!vma \|\| (vma->vm_flags & (VM_IO \| VM_RESERVED))
		if (!vma \|\| (vma->vm_flags & VM_IO)
		\|\| !(vm_flags & vma->vm_flags))
		return i ? : -EFAULT;

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