ipc: constify ipc_ops

There is no need to recreate the very same ipc_ops structure on every
kernel entry for msgget/semget/shmget.  Just declare it static and be
done with it.  While at it, constify it as we don't modify the structure
at runtime.

Found in the PaX patch, written by the PaX Team.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Cc: PaX Team <pageexec@freemail.hu>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/ipc/util.c b/ipc/util.c
index 2eb0d1e..9b3fa38 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -317,7 +317,7 @@
  * when the key is IPC_PRIVATE.
  */
 static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
-		struct ipc_ops *ops, struct ipc_params *params)
+		const struct ipc_ops *ops, struct ipc_params *params)
 {
 	int err;
 
@@ -344,7 +344,7 @@
  */
 static int ipc_check_perms(struct ipc_namespace *ns,
 			   struct kern_ipc_perm *ipcp,
-			   struct ipc_ops *ops,
+			   const struct ipc_ops *ops,
 			   struct ipc_params *params)
 {
 	int err;
@@ -375,7 +375,7 @@
  * On success, the ipc id is returned.
  */
 static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
-		struct ipc_ops *ops, struct ipc_params *params)
+		const struct ipc_ops *ops, struct ipc_params *params)
 {
 	struct kern_ipc_perm *ipcp;
 	int flg = params->flg;
@@ -678,7 +678,7 @@
  * Common routine called by sys_msgget(), sys_semget() and sys_shmget().
  */
 int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
-			struct ipc_ops *ops, struct ipc_params *params)
+			const struct ipc_ops *ops, struct ipc_params *params)
 {
 	if (params->key == IPC_PRIVATE)
 		return ipcget_new(ns, ids, ops, params);