From d98c7a09843621f1b145ca5ae8ed03ff04085edb Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 14 Feb 2006 13:52:59 -0800 Subject: [PATCH] [PATCH] compound page: default destructor Somehow I imagined that calling a NULL destructor would free a compound page rather than oopsing. No, we must supply a default destructor, __free_pages_ok using the order noted by prep_compound_page. hugetlb can still replace this as before with its own free_huge_page pointer. The case that needs this is not common: rarely does put_compound_page's put_page_testzero bring the count down to 0. But if get_user_pages is applied to some part of a compound page, without immediate release (e.g. AIO or Infiniband), then it's possible for its put_page to come after the containing vma has been unmapped and the driver done its free_pages. That's just the kind of case compound pages are supposed to be guarding against (but Nick points out, nor did PageReserved handle this right). Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-format-patch failed