cleancache: Make cleancache_init use a pointer for the ops

Instead of using a backend_registered to determine whether a backend is
enabled.  This allows us to remove the backend_register check and just
do 'if (cleancache_ops)'

[v1: Rebase on top of b97c4b430b0a (ramster->zcache move]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Andor Daam <andor.daam@googlemail.com>
Cc: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Florian Schmaus <fschmaus@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Stefan Hengelein <ilendir@googlemail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
index 7a01a5fd0f63..fd79eab08368 100644
--- a/drivers/xen/tmem.c
+++ b/drivers/xen/tmem.c
@@ -236,7 +236,7 @@ static int __init no_cleancache(char *s)
 }
 __setup("nocleancache", no_cleancache);
 
-static struct cleancache_ops __initdata tmem_cleancache_ops = {
+static struct cleancache_ops tmem_cleancache_ops = {
         .put_page = tmem_cleancache_put_page,
         .get_page = tmem_cleancache_get_page,
         .invalidate_page = tmem_cleancache_flush_page,
@@ -392,9 +392,9 @@ static int __init xen_tmem_init(void)
         BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
         if (tmem_enabled && use_cleancache) {
                 char *s = "";
-                struct cleancache_ops old_ops =
+                struct cleancache_ops *old_ops =
                         cleancache_register_ops(&tmem_cleancache_ops);
-                if (old_ops.init_fs != NULL)
+                if (old_ops)
                         s = " (WARNING: cleancache_ops overridden)";
                 printk(KERN_INFO "cleancache enabled, RAM provided by "
                                  "Xen Transcendent Memory%s\n", s);