From: Andrew Morton <akpm@linux-foundation.org>

ERROR: "page_address" [async_tx/async_memset.ko] undefined!

Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 async_tx/async_memset.c |    1 +
 1 file changed, 1 insertion(+)

diff -puN async_tx/async_memset.c~git-md-accel-build-fix async_tx/async_memset.c
--- a/async_tx/async_memset.c~git-md-accel-build-fix
+++ a/async_tx/async_memset.c
@@ -25,6 +25,7 @@
  * file called COPYING.
  */
 #include <linux/kernel.h>
+#include <linux/mm.h>
 #include <linux/interrupt.h>
 #include <linux/dma-mapping.h>
 #include <linux/async_tx.h>
_