[PATCH 1/4] mm/page_alloc.c: extract commom part to check page

[Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>]

During free and new page, we did some check on the status of page
struct.

There is some common part, just extract them.

Signed-off-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
---
 mm/page_alloc.c | 36 ++++++++++++++++--------------------
 1 file changed, 16 insertions(+), 20 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d047bf7d8fd4..8cd06729169f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1025,13 +1025,9 @@ static inline bool page_expected_state(struct page *page,
 	return true;
 }
 
-static void free_pages_check_bad(struct page *page)
+static inline const char *__check_page(struct page *page)
 {
-	const char *bad_reason;
-	unsigned long bad_flags;
-
-	bad_reason = NULL;
-	bad_flags = 0;
+	const char *bad_reason = NULL;
 
 	if (unlikely(atomic_read(&page->_mapcount) != -1))
 		bad_reason = "nonzero mapcount";
@@ -1039,14 +1035,23 @@ static void free_pages_check_bad(struct page *page)
 		bad_reason = "non-NULL mapping";
 	if (unlikely(page_ref_count(page) != 0))
 		bad_reason = "nonzero _refcount";
-	if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
-		bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
-		bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
-	}
 #ifdef CONFIG_MEMCG
 	if (unlikely(page->mem_cgroup))
 		bad_reason = "page still charged to cgroup";
 #endif
+	return bad_reason;
+}
+
+static void free_pages_check_bad(struct page *page)
+{
+	const char *bad_reason = NULL;
+	unsigned long bad_flags = 0;
+
+	bad_reason = __check_page(page);
+	if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_FREE)) {
+		bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
+		bad_flags = PAGE_FLAGS_CHECK_AT_FREE;
+	}
 	bad_page(page, bad_reason, bad_flags);
 }
 
@@ -2044,12 +2049,7 @@ static void check_new_page_bad(struct page *page)
 	const char *bad_reason = NULL;
 	unsigned long bad_flags = 0;
 
-	if (unlikely(atomic_read(&page->_mapcount) != -1))
-		bad_reason = "nonzero mapcount";
-	if (unlikely(page->mapping != NULL))
-		bad_reason = "non-NULL mapping";
-	if (unlikely(page_ref_count(page) != 0))
-		bad_reason = "nonzero _refcount";
+	bad_reason = __check_page(page);
 	if (unlikely(page->flags & __PG_HWPOISON)) {
 		bad_reason = "HWPoisoned (hardware-corrupted)";
 		bad_flags = __PG_HWPOISON;
@@ -2061,10 +2061,6 @@ static void check_new_page_bad(struct page *page)
 		bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
 		bad_flags = PAGE_FLAGS_CHECK_AT_PREP;
 	}
-#ifdef CONFIG_MEMCG
-	if (unlikely(page->mem_cgroup))
-		bad_reason = "page still charged to cgroup";
-#endif
 	bad_page(page, bad_reason, bad_flags);
 }
 
-- 
2.17.1