[PATCH 01/11] unpaged: get_user_pages VM_RESERVED

Hugh Dickins
2005-11-17T19:30:37Z

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>
---

mm/memory.c | 2 +-
1 files changed, 1 insertion(+), 1 deletion(-)

--- 2.6.15-rc1-git5/mm/memory.c 2005-11-17 13:53:21.000000000 +0000
+++ unpaged01/mm/memory.c 2005-11-17 15:10:08.000000000 +0000
@@ -968,7 +968,7 @@ int get_user_pages(struct task_struct *t
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;