1 files changed, 12 insertions, 65 deletions

diff --git a/mm/page_poison.c b/mm/page_poison.c
index 2e647c65916b..be19e989ccff 100644
--- a/mm/page_poison.c
+++ b/mm/page_poison.c
@@ -6,7 +6,6 @@
 #include <linux/poison.h>
 #include <linux/ratelimit.h>
 
-static bool __page_poisoning_enabled __read_mostly;
 static bool want_page_poisoning __read_mostly;
 
 static int early_page_poison_param(char *buf)
@@ -19,74 +18,21 @@ early_param("page_poison", early_page_poison_param);
 
 bool page_poisoning_enabled(void)
 {
-	return __page_poisoning_enabled;
-}
-
-static bool need_page_poisoning(void)
-{
-	return want_page_poisoning;
-}
-
-static void init_page_poisoning(void)
-{
 	/*
-	 * page poisoning is debug page alloc for some arches. If either
-	 * of those options are enabled, enable poisoning
+	 * Assumes that debug_pagealloc_enabled is set before
+	 * free_all_bootmem.
+	 * Page poisoning is debug page alloc for some arches. If
+	 * either of those options are enabled, enable poisoning.
 	 */
-	if (!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC)) {
-		if (!want_page_poisoning && !debug_pagealloc_enabled())
-			return;
-	} else {
-		if (!want_page_poisoning)
-			return;
-	}
-
-	__page_poisoning_enabled = true;
-}
-
-struct page_ext_operations page_poisoning_ops = {
-	.need = need_page_poisoning,
-	.init = init_page_poisoning,
-};
-
-static inline void set_page_poison(struct page *page)
-{
-	struct page_ext *page_ext;
-
-	page_ext = lookup_page_ext(page);
-	if (unlikely(!page_ext))
-		return;
-
-	__set_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
-}
-
-static inline void clear_page_poison(struct page *page)
-{
-	struct page_ext *page_ext;
-
-	page_ext = lookup_page_ext(page);
-	if (unlikely(!page_ext))
-		return;
-
-	__clear_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
-}
-
-bool page_is_poisoned(struct page *page)
-{
-	struct page_ext *page_ext;
-
-	page_ext = lookup_page_ext(page);
-	if (unlikely(!page_ext))
-		return false;
-
-	return test_bit(PAGE_EXT_DEBUG_POISON, &page_ext->flags);
+	return (want_page_poisoning ||
+		(!IS_ENABLED(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) &&
+		debug_pagealloc_enabled()));
 }
 
 static void poison_page(struct page *page)
 {
 	void *addr = kmap_atomic(page);
 
-	set_page_poison(page);
 	memset(addr, PAGE_POISON, PAGE_SIZE);
 	kunmap_atomic(addr);
 }
@@ -140,12 +86,13 @@ static void unpoison_page(struct page *page)
 {
 	void *addr;
 
-	if (!page_is_poisoned(page))
-		return;
-
 	addr = kmap_atomic(page);
+	/*
+	 * Page poisoning when enabled poisons each and every page
+	 * that is freed to buddy. Thus no extra check is done to
+	 * see if a page was posioned.
+	 */
 	check_poison_mem(addr, PAGE_SIZE);
-	clear_page_poison(page);
 	kunmap_atomic(addr);
 }