diff options
author | Hugh Dickins <hugh@veritas.com> | 2006-02-14 13:52:59 -0800 |
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committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-02-14 16:09:33 -0800 |
commit | d98c7a09843621f1b145ca5ae8ed03ff04085edb (patch) | |
tree | 764b943efb177ca506fad61a63bb9e8cbf56a3a7 /kernel | |
parent | 41d78ba55037468e6c86c53e3076d1a74841de39 (diff) |
[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 <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
0 files changed, 0 insertions, 0 deletions