cleancache: constify cleancache_ops structure

The cleancache_ops structure is never modified, so declare it as const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/mm/cleancache.c b/mm/cleancache.c
index 8fc5081..ba5d8f3 100644
--- a/mm/cleancache.c
+++ b/mm/cleancache.c
@@ -22,7 +22,7 @@
  * cleancache_ops is set by cleancache_register_ops to contain the pointers
  * to the cleancache "backend" implementation functions.
  */
-static struct cleancache_ops *cleancache_ops __read_mostly;
+static const struct cleancache_ops *cleancache_ops __read_mostly;
 
 /*
  * Counters available via /sys/kernel/debug/cleancache (if debugfs is
@@ -49,7 +49,7 @@
 /*
  * Register operations for cleancache. Returns 0 on success.
  */
-int cleancache_register_ops(struct cleancache_ops *ops)
+int cleancache_register_ops(const struct cleancache_ops *ops)
 {
 	if (cmpxchg(&cleancache_ops, NULL, ops))
 		return -EBUSY;