Commit 28e4d965 authored Sep 25, 2006 by Nick Piggin Committed by Linus Torvalds Sep 26, 2006

[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>

parent bfa5bf6d

mm/vmscan.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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:

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