[PATCH] mm: remove_mapping() safeness

Some users of remove_mapping had been unsafe.

Modify the remove_mapping precondition to ensure the caller has locked the
page and obtained the correct mapping.  Modify callers to ensure the
mapping is the correct one.

[hugh@veritas.com: swapper_space fix]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Nick Piggin 2006-09-25 23:31:23 -07:00 committed by Linus Torvalds
parent bfa5bf6d64
commit 28e4d965e6

View File

@ -377,8 +377,8 @@ static pageout_t pageout(struct page *page, struct address_space *mapping)
int remove_mapping(struct address_space *mapping, struct page *page)
{
if (!mapping)
return 0; /* truncate got there first */
BUG_ON(!PageLocked(page));
BUG_ON(mapping != page_mapping(page));
write_lock_irq(&mapping->tree_lock);
@ -547,7 +547,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
goto free_it;
}
if (!remove_mapping(mapping, page))
if (!mapping || !remove_mapping(mapping, page))
goto keep_locked;
free_it: