[PATCH] kmemtrace: fix build breakage in linux/key.h

[Pekka Enberg <penberg@cs.helsinki.fi>]

From: Pekka Enberg <penberg@cs.helsinki.fi>

Impact: fix build

This patch fixes up the following build breakage caused by commit
e251ea2fa52321009940fad02238ef1c369531ae ("rcu: don't include unnecessary
headers, allow kmemtrace w/ tracepoints"):

    CC [M]  fs/cifs/cifs_spnego.o
  In file included from include/keys/user-type.h:15,
                   from fs/cifs/cifs_spnego.c:24:
  include/linux/key.h:128: error: field ‘sem’ has incomplete type
  make[2]: *** [fs/cifs/cifs_spnego.o] Error 1
  make[1]: *** [fs/cifs] Error 2
  make: *** [fs] Error 2

Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
---
 include/linux/key.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/include/linux/key.h b/include/linux/key.h
index 21d32a1..e544f46 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -20,6 +20,7 @@
 #include <linux/rbtree.h>
 #include <linux/rcupdate.h>
 #include <linux/sysctl.h>
+#include <linux/rwsem.h>
 #include <asm/atomic.h>
 
 #ifdef __KERNEL__
-- 
1.5.4.3