From: David Rientjes <rientjes@google.com>

/proc/pid/clear_refs is only defined in the CONFIG_MMU case, so make sure we
don't have any references to clear_refs_smap() in generic procfs code.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/proc/base.c |    2 ++
 1 file changed, 2 insertions(+)

diff -puN fs/proc/base.c~smaps-only-define-clear_refs-for-config_mmu fs/proc/base.c
--- a/fs/proc/base.c~smaps-only-define-clear_refs-for-config_mmu
+++ a/fs/proc/base.c
@@ -708,6 +708,7 @@ static const struct file_operations proc
 	.write		= oom_adjust_write,
 };
 
+#ifdef CONFIG_MMU
 static ssize_t clear_refs_write(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos)
 {
@@ -741,6 +742,7 @@ static ssize_t clear_refs_write(struct f
 static struct file_operations proc_clear_refs_operations = {
 	.write		= clear_refs_write,
 };
+#endif
 
 #ifdef CONFIG_AUDITSYSCALL
 #define TMPBUFLEN 21
_