mm: uninline and cleanup page-mapping related helpers

Most-used page->mapping helper -- page_mapping() -- has already uninlined.
 Let's uninline also page_rmapping() and page_anon_vma().  It saves us
depending on configuration around 400 bytes in text:

   text	   data	    bss	    dec	    hex	filename
 660318	  99254	 410000	1169572	 11d8a4	mm/built-in.o-before
 659854	  99254	 410000	1169108	 11d6d4	mm/built-in.o

I also tried to make code a bit more clean.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 36 insertions, 5 deletions

diff --git a/mm/util.c b/mm/util.c
index 3981ae9d1b15..68ff8a5361e7 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -325,9 +325,37 @@ void kvfree(const void *addr)
 }
 EXPORT_SYMBOL(kvfree);
 
+static inline void *__page_rmapping(struct page *page)
+{
+	unsigned long mapping;
+
+	mapping = (unsigned long)page->mapping;
+	mapping &= ~PAGE_MAPPING_FLAGS;
+
+	return (void *)mapping;
+}
+
+/* Neutral page->mapping pointer to address_space or anon_vma or other */
+void *page_rmapping(struct page *page)
+{
+	page = compound_head(page);
+	return __page_rmapping(page);
+}
+
+struct anon_vma *page_anon_vma(struct page *page)
+{
+	unsigned long mapping;
+
+	page = compound_head(page);
+	mapping = (unsigned long)page->mapping;
+	if ((mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
+		return NULL;
+	return __page_rmapping(page);
+}
+
 struct address_space *page_mapping(struct page *page)
 {
-	struct address_space *mapping = page->mapping;
+	unsigned long mapping;
 
 	/* This happens if someone calls flush_dcache_page on slab page */
 	if (unlikely(PageSlab(page)))
@@ -337,10 +365,13 @@ struct address_space *page_mapping(struct page *page)
 		swp_entry_t entry;
 
 		entry.val = page_private(page);
-		mapping = swap_address_space(entry);
-	} else if ((unsigned long)mapping & PAGE_MAPPING_ANON)
-		mapping = NULL;
-	return mapping;
+		return swap_address_space(entry);
+	}
+
+	mapping = (unsigned long)page->mapping;
+	if (mapping & PAGE_MAPPING_FLAGS)
+		return NULL;
+	return page->mapping;
 }
 
 int overcommit_ratio_handler(struct ctl_table *table, int write,