[PATCH] mm: huge_memory: Fix build error.

[Ralf Baechle <ralf@linux-mips.org>]

Certain configurations won't implicitly pull in <linux/pagemap.h> resulting
in the following build error:

mm/huge_memory.c: In function 'release_pte_page':
mm/huge_memory.c:1697:2: error: implicit declaration of function 'unlock_page' 
[-Werror=implicit-function-declaration]
mm/huge_memory.c: In function '__collapse_huge_page_isolate':
mm/huge_memory.c:1757:3: error: implicit declaration of function 'trylock_page' 
[-Werror=implicit-function-declaration]
cc1: some warnings being treated as errors

Reported-by: David Daney <david.daney@cavium.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
 mm/huge_memory.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f0e5306..b5d4eb8 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -17,6 +17,7 @@
 #include <linux/khugepaged.h>
 #include <linux/freezer.h>
 #include <linux/mman.h>
+#include <linux/pagemap.h>
 #include <asm/tlb.h>
 #include <asm/pgalloc.h>
 #include "internal.h"