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>

1 files changed, 21 insertions, 22 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 43a224f..865d89a 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -818,7 +818,7 @@ static int cgroup_call_pre_destroy(struct cgroup *cgrp)
 
 	for_each_subsys(cgrp->root, ss)
 		if (ss->pre_destroy) {
-			ret = ss->pre_destroy(ss, cgrp);
+			ret = ss->pre_destroy(cgrp);
 			if (ret)
 				break;
 		}
@@ -846,7 +846,7 @@ static void cgroup_diput(struct dentry *dentry, struct inode *inode)
 		 * Release the subsystem state objects.
 		 */
 		for_each_subsys(cgrp->root, ss)
-			ss->destroy(ss, cgrp);
+			ss->destroy(cgrp);
 
 		cgrp->root->number_of_cgroups--;
 		mutex_unlock(&cgroup_mutex);
@@ -1015,7 +1015,7 @@ static int rebind_subsystems(struct cgroupfs_root *root,
 			list_move(&ss->sibling, &root->subsys_list);
 			ss->root = root;
 			if (ss->bind)
-				ss->bind(ss, cgrp);
+				ss->bind(cgrp);
 			mutex_unlock(&ss->hierarchy_mutex);
 			/* refcount was already taken, and we're keeping it */
 		} else if (bit & removed_bits) {
@@ -1025,7 +1025,7 @@ static int rebind_subsystems(struct cgroupfs_root *root,
 			BUG_ON(cgrp->subsys[i]->cgroup != cgrp);
 			mutex_lock(&ss->hierarchy_mutex);
 			if (ss->bind)
-				ss->bind(ss, dummytop);
+				ss->bind(dummytop);
 			dummytop->subsys[i]->cgroup = dummytop;
 			cgrp->subsys[i] = NULL;
 			subsys[i]->root = &rootnode;
@@ -1908,7 +1908,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
 
 	for_each_subsys(root, ss) {
 		if (ss->can_attach) {
-			retval = ss->can_attach(ss, cgrp, &tset);
+			retval = ss->can_attach(cgrp, &tset);
 			if (retval) {
 				/*
 				 * Remember on which subsystem the can_attach()
@@ -1932,7 +1932,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
 
 	for_each_subsys(root, ss) {
 		if (ss->attach)
-			ss->attach(ss, cgrp, &tset);
+			ss->attach(cgrp, &tset);
 	}
 
 	synchronize_rcu();
@@ -1954,7 +1954,7 @@ out:
 				 */
 				break;
 			if (ss->cancel_attach)
-				ss->cancel_attach(ss, cgrp, &tset);
+				ss->cancel_attach(cgrp, &tset);
 		}
 	}
 	return retval;
@@ -2067,7 +2067,7 @@ static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
 	 */
 	for_each_subsys(root, ss) {
 		if (ss->can_attach) {
-			retval = ss->can_attach(ss, cgrp, &tset);
+			retval = ss->can_attach(cgrp, &tset);
 			if (retval) {
 				failed_ss = ss;
 				goto out_cancel_attach;
@@ -2104,7 +2104,7 @@ static int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
 	 */
 	for_each_subsys(root, ss) {
 		if (ss->attach)
-			ss->attach(ss, cgrp, &tset);
+			ss->attach(cgrp, &tset);
 	}
 
 	/*
@@ -2128,7 +2128,7 @@ out_cancel_attach:
 			if (ss == failed_ss)
 				break;
 			if (ss->cancel_attach)
-				ss->cancel_attach(ss, cgrp, &tset);
+				ss->cancel_attach(cgrp, &tset);
 		}
 	}
 out_free_group_list:
@@ -3756,7 +3756,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
 		set_bit(CGRP_CLONE_CHILDREN, &cgrp->flags);
 
 	for_each_subsys(root, ss) {
-		struct cgroup_subsys_state *css = ss->create(ss, cgrp);
+		struct cgroup_subsys_state *css = ss->create(cgrp);
 
 		if (IS_ERR(css)) {
 			err = PTR_ERR(css);
@@ -3770,7 +3770,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
 		}
 		/* At error, ->destroy() callback has to free assigned ID. */
 		if (clone_children(parent) && ss->post_clone)
-			ss->post_clone(ss, cgrp);
+			ss->post_clone(cgrp);
 	}
 
 	cgroup_lock_hierarchy(root);
@@ -3804,7 +3804,7 @@ static long cgroup_create(struct cgroup *parent, struct dentry *dentry,
 
 	for_each_subsys(root, ss) {
 		if (cgrp->subsys[ss->subsys_id])
-			ss->destroy(ss, cgrp);
+			ss->destroy(cgrp);
 	}
 
 	mutex_unlock(&cgroup_mutex);
@@ -4028,7 +4028,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss)
 	/* Create the top cgroup state for this subsystem */
 	list_add(&ss->sibling, &rootnode.subsys_list);
 	ss->root = &rootnode;
-	css = ss->create(ss, dummytop);
+	css = ss->create(dummytop);
 	/* We don't handle early failures gracefully */
 	BUG_ON(IS_ERR(css));
 	init_cgroup_css(css, ss, dummytop);
@@ -4117,7 +4117,7 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
 	 * no ss->create seems to need anything important in the ss struct, so
 	 * this can happen first (i.e. before the rootnode attachment).
 	 */
-	css = ss->create(ss, dummytop);
+	css = ss->create(dummytop);
 	if (IS_ERR(css)) {
 		/* failure case - need to deassign the subsys[] slot. */
 		subsys[i] = NULL;
@@ -4135,7 +4135,7 @@ int __init_or_module cgroup_load_subsys(struct cgroup_subsys *ss)
 		int ret = cgroup_init_idr(ss, css);
 		if (ret) {
 			dummytop->subsys[ss->subsys_id] = NULL;
-			ss->destroy(ss, dummytop);
+			ss->destroy(dummytop);
 			subsys[i] = NULL;
 			mutex_unlock(&cgroup_mutex);
 			return ret;
@@ -4233,7 +4233,7 @@ void cgroup_unload_subsys(struct cgroup_subsys *ss)
 	 * pointer to find their state. note that this also takes care of
 	 * freeing the css_id.
 	 */
-	ss->destroy(ss, dummytop);
+	ss->destroy(dummytop);
 	dummytop->subsys[ss->subsys_id] = NULL;
 
 	mutex_unlock(&cgroup_mutex);
@@ -4509,7 +4509,7 @@ void cgroup_fork_callbacks(struct task_struct *child)
 		for (i = 0; i < CGROUP_BUILTIN_SUBSYS_COUNT; i++) {
 			struct cgroup_subsys *ss = subsys[i];
 			if (ss->fork)
-				ss->fork(ss, child);
+				ss->fork(child);
 		}
 	}
 }
@@ -4611,7 +4611,7 @@ void cgroup_exit(struct task_struct *tsk, int run_callbacks)
 				struct cgroup *old_cgrp =
 					rcu_dereference_raw(cg->subsys[i])->cgroup;
 				struct cgroup *cgrp = task_cgroup(tsk, i);
-				ss->exit(ss, cgrp, old_cgrp, tsk);
+				ss->exit(cgrp, old_cgrp, tsk);
 			}
 		}
 	}
@@ -5066,8 +5066,7 @@ struct cgroup_subsys_state *cgroup_css_from_dir(struct file *f, int id)
 }
 
 #ifdef CONFIG_CGROUP_DEBUG
-static struct cgroup_subsys_state *debug_create(struct cgroup_subsys *ss,
-						   struct cgroup *cont)
+static struct cgroup_subsys_state *debug_create(struct cgroup *cont)
 {
 	struct cgroup_subsys_state *css = kzalloc(sizeof(*css), GFP_KERNEL);
 
@@ -5077,7 +5076,7 @@ static struct cgroup_subsys_state *debug_create(struct cgroup_subsys *ss,
 	return css;
 }
 
-static void debug_destroy(struct cgroup_subsys *ss, struct cgroup *cont)
+static void debug_destroy(struct cgroup *cont)
 {
 	kfree(cont->subsys[debug_subsys_id]);
 }