/proc/pid/pagemap: fix PM_SPECIAL macro

There seems to be a bug in the PM_SPECIAL macro for /proc/pid/pagemap.  I
think masking out those other bits makes more sense then setting all those
mask bits.

Signed-off-by: Hans Rosenfeld <Hans.Rosenfeld@amd.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/task_mmu.c

@@ -531,7 +531,7 @@ struct pagemapread {
 #define PM_RESERVED_BITS    3
 #define PM_RESERVED_OFFSET  (64 - PM_RESERVED_BITS)
 #define PM_RESERVED_MASK    (((1LL<<PM_RESERVED_BITS)-1) << PM_RESERVED_OFFSET)
-#define PM_SPECIAL(nr)      (((nr) << PM_RESERVED_OFFSET) | PM_RESERVED_MASK)
+#define PM_SPECIAL(nr)      (((nr) << PM_RESERVED_OFFSET) & PM_RESERVED_MASK)
 #define PM_NOT_PRESENT      PM_SPECIAL(1LL)
 #define PM_SWAP             PM_SPECIAL(2LL)
 #define PM_END_OF_BUFFER    1