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);
 }