memory-failure: export page_type and action result

Export 'outcome' and 'action_page_type' to mm.h, so we could use
this emnus outside.

This patch is preparation for adding trace events for memory-failure
recovery action.

Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Cc: Jim Davis <jim.epost@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/mm.h

@@ -2153,6 +2153,40 @@ extern void shake_page(struct page *p, int access);
 extern atomic_long_t num_poisoned_pages;
 extern int soft_offline_page(struct page *page, int flags);
 
+
+/*
+ * Error handlers for various types of pages.
+ */
+enum mf_outcome {
+	MF_IGNORED,	/* Error: cannot be handled */
+	MF_FAILED,	/* Error: handling failed */
+	MF_DELAYED,	/* Will be handled later */
+	MF_RECOVERED,	/* Successfully recovered */
+};
+
+enum mf_action_page_type {
+	MF_MSG_KERNEL,
+	MF_MSG_KERNEL_HIGH_ORDER,
+	MF_MSG_SLAB,
+	MF_MSG_DIFFERENT_COMPOUND,
+	MF_MSG_POISONED_HUGE,
+	MF_MSG_HUGE,
+	MF_MSG_FREE_HUGE,
+	MF_MSG_UNMAP_FAILED,
+	MF_MSG_DIRTY_SWAPCACHE,
+	MF_MSG_CLEAN_SWAPCACHE,
+	MF_MSG_DIRTY_MLOCKED_LRU,
+	MF_MSG_CLEAN_MLOCKED_LRU,
+	MF_MSG_DIRTY_UNEVICTABLE_LRU,
+	MF_MSG_CLEAN_UNEVICTABLE_LRU,
+	MF_MSG_DIRTY_LRU,
+	MF_MSG_CLEAN_LRU,
+	MF_MSG_TRUNCATED_LRU,
+	MF_MSG_BUDDY,
+	MF_MSG_BUDDY_2ND,
+	MF_MSG_UNKNOWN,
+};
+
 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
 extern void clear_huge_page(struct page *page,
 			    unsigned long addr,