[PATCH] mm: Make {,set}page_address() static inline if WANT_PAGE_VIRTUAL

[Geert Uytterhoeven <geert@linux-m68k.org>]

{,set}page_address() are macros if WANT_PAGE_VIRTUAL.
If !WANT_PAGE_VIRTUAL, they're plain C functions.

If someone calls them with a void *, this pointer is auto-converted to
struct page * if !WANT_PAGE_VIRTUAL, but causes a build failure on
architectures using WANT_PAGE_VIRTUAL (arc, m68k and sparc):

drivers/md/bcache/bset.c: In function a??__btree_sorta??:
drivers/md/bcache/bset.c:1190: warning: dereferencing a??void *a?? pointer
drivers/md/bcache/bset.c:1190: error: request for member a??virtuala?? in something not a structure or union

Convert them to static inline functions to fix this. There are already
plenty of  users of struct page members inside <linux/mm.h>, so there's no
reason to keep them as macros.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
http://kisskb.ellerman.id.au/kisskb/buildresult/10469287/ (m68k/next)
http://kisskb.ellerman.id.au/kisskb/buildresult/10469488/ (sparc64/next)
https://lkml.org/lkml/2014/1/13/1044 (m68k & sparc/3.10.27-stable)

 include/linux/mm.h |   13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 35527173cf50..9fac6dd69b11 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -846,11 +846,14 @@ static __always_inline void *lowmem_page_address(const struct page *page)
 #endif
 
 #if defined(WANT_PAGE_VIRTUAL)
-#define page_address(page) ((page)->virtual)
-#define set_page_address(page, address)			\
-	do {						\
-		(page)->virtual = (address);		\
-	} while(0)
+static inline void *page_address(const struct page *page)
+{
+	return page->virtual;
+}
+static inline void set_page_address(struct page *page, void *address)
+{
+	page->virtual = address;
+}
 #define page_address_init()  do { } while(0)
 #endif
 
-- 
1.7.9.5

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