mm/page_alloc.c: extract check_[new|free]_page_bad() common part to page_bad_reason()

We share similar code in check_[new|free]_page_bad() to get the page's bad
reason.

Let's extract it and reduce code duplication.

Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/20200411220357.9636-6-richard.weiyang@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 57c497d32738c54533c0673db91b68bacc3660d5..cbe73a5610a152a21c117507cdb45bc08acf8130 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1070,7 +1070,7 @@ static inline bool page_expected_state(struct page *page,
        return true;
 }
 
-static void check_free_page_bad(struct page *page)
+static const char *page_bad_reason(struct page *page, unsigned long flags)
 {
        const char *bad_reason = NULL;
 
@@ -1080,13 +1080,23 @@ static void check_free_page_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";
+       if (unlikely(page->flags & flags)) {
+               if (flags == PAGE_FLAGS_CHECK_AT_PREP)
+                       bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag(s) set";
+               else
+                       bad_reason = "PAGE_FLAGS_CHECK_AT_FREE flag(s) set";
+       }
 #ifdef CONFIG_MEMCG
        if (unlikely(page->mem_cgroup))
                bad_reason = "page still charged to cgroup";
 #endif
-       bad_page(page, bad_reason);
+       return bad_reason;
+}
+
+static void check_free_page_bad(struct page *page)
+{
+       bad_page(page,
+                page_bad_reason(page, PAGE_FLAGS_CHECK_AT_FREE));
 }
 
 static inline int check_free_page(struct page *page)
@@ -2083,26 +2093,14 @@ static inline void expand(struct zone *zone, struct page *page,
 
 static void check_new_page_bad(struct page *page)
 {
-       const char *bad_reason = NULL;
-
        if (unlikely(page->flags & __PG_HWPOISON)) {
                /* Don't complain about hwpoisoned pages */
                page_mapcount_reset(page); /* remove PageBuddy */
                return;
        }
-       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";
-       if (unlikely(page->flags & PAGE_FLAGS_CHECK_AT_PREP))
-               bad_reason = "PAGE_FLAGS_CHECK_AT_PREP flag set";
-#ifdef CONFIG_MEMCG
-       if (unlikely(page->mem_cgroup))
-               bad_reason = "page still charged to cgroup";
-#endif
-       bad_page(page, bad_reason);
+
+       bad_page(page,
+                page_bad_reason(page, PAGE_FLAGS_CHECK_AT_PREP));
 }
 
 /*