badpage: simplify page_alloc flag check+clear
Simplify the PAGE_FLAGS checking and clearing when freeing and allocating
a page: check the same flags as before when freeing, clear ALL the flags
(unless PageReserved) when freeing, check ALL flags off when allocating.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 628ec080..219a523 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -373,31 +373,22 @@
#define __PG_MLOCKED 0
#endif
-#define PAGE_FLAGS (1 << PG_lru | 1 << PG_private | 1 << PG_locked | \
- 1 << PG_buddy | 1 << PG_writeback | \
- 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
- __PG_UNEVICTABLE | __PG_MLOCKED)
-
-/*
- * Flags checked in bad_page(). Pages on the free list should not have
- * these flags set. It they are, there is a problem.
- */
-#define PAGE_FLAGS_CLEAR_WHEN_BAD (PAGE_FLAGS | \
- 1 << PG_reclaim | 1 << PG_dirty | 1 << PG_swapbacked)
-
/*
* Flags checked when a page is freed. Pages being freed should not have
* these flags set. It they are, there is a problem.
*/
-#define PAGE_FLAGS_CHECK_AT_FREE (PAGE_FLAGS | 1 << PG_reserved)
+#define PAGE_FLAGS_CHECK_AT_FREE \
+ (1 << PG_lru | 1 << PG_private | 1 << PG_locked | \
+ 1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \
+ 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
+ __PG_UNEVICTABLE | __PG_MLOCKED)
/*
* Flags checked when a page is prepped for return by the page allocator.
- * Pages being prepped should not have these flags set. It they are, there
- * is a problem.
+ * Pages being prepped should not have any flags set. It they are set,
+ * there has been a kernel bug or struct page corruption.
*/
-#define PAGE_FLAGS_CHECK_AT_PREP (PAGE_FLAGS | \
- 1 << PG_reserved | 1 << PG_dirty | 1 << PG_swapbacked)
+#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1)
#endif /* !__GENERATING_BOUNDS_H */
#endif /* PAGE_FLAGS_H */