cgroup: remove cgroup_subsys argument from callbacks

The argument is not used at all, and it's not necessary, because
a specific callback handler of course knows which subsys it
belongs to.

Now only ->pupulate() takes this argument, because the handlers of
this callback always call cgroup_add_file()/cgroup_add_files().

So we reduce a few lines of code, though the shrinking of object size
is minimal.

 16 files changed, 113 insertions(+), 162 deletions(-)

   text    data     bss     dec     hex filename
5486240  656987 7039960 13183187         c928d3 vmlinux.o.orig
5486170  656987 7039960 13183117         c9288d vmlinux.o

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index 3a9fd48..22036ab 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c
@@ -23,9 +23,8 @@
 #include <net/sock.h>
 #include <net/netprio_cgroup.h>
 
-static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
-					       struct cgroup *cgrp);
-static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp);
+static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp);
+static void cgrp_destroy(struct cgroup *cgrp);
 static int cgrp_populate(struct cgroup_subsys *ss, struct cgroup *cgrp);
 
 struct cgroup_subsys net_prio_subsys = {
@@ -120,8 +119,7 @@
 	rtnl_unlock();
 }
 
-static struct cgroup_subsys_state *cgrp_create(struct cgroup_subsys *ss,
-						 struct cgroup *cgrp)
+static struct cgroup_subsys_state *cgrp_create(struct cgroup *cgrp)
 {
 	struct cgroup_netprio_state *cs;
 	int ret;
@@ -145,7 +143,7 @@
 	return &cs->css;
 }
 
-static void cgrp_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
+static void cgrp_destroy(struct cgroup *cgrp)
 {
 	struct cgroup_netprio_state *cs;
 	struct net_device *dev;