kabi: reserve space for cgroup framework related structures

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4GII8?from=project-issue
CVE: NA

--------

We reserve some fields beforehand for cgroup framework related structures prone
to change, therefore, we can hot add/change features of cgroupv1/cgroupv2 with
this enhancement.

After reserving, normally cache does not matter as the reserved fields
are not accessed at all.

---------
Signed-off-by: NLu Jialin <lujialin4@huawei.com>
Reviewed-by: Nweiyang wang <wangweiyang2@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/cgroup-defs.h

@@ -21,6 +21,7 @@
 #include <linux/workqueue.h>
 #include <linux/bpf-cgroup.h>
 #include <linux/psi_types.h>
+#include <linux/kabi.h>
 
 #ifdef CONFIG_CGROUPS
 
@@ -126,6 +127,9 @@ struct cgroup_file {
 	struct kernfs_node *kn;
 	unsigned long notified_at;
 	struct timer_list notify_timer;
+
+	KABI_RESERVE(1)
+	KABI_RESERVE(2)
 };
 
 /*
@@ -183,6 +187,11 @@ struct cgroup_subsys_state {
 	 * fields of the containing structure.
 	 */
 	struct cgroup_subsys_state *parent;
+
+	KABI_RESERVE(1)
+	KABI_RESERVE(2)
+	KABI_RESERVE(3)
+	KABI_RESERVE(4)
 };
 
 /*
@@ -279,6 +288,11 @@ struct css_set {
 
 	/* For RCU-protected deletion */
 	struct rcu_head rcu_head;
+
+	KABI_RESERVE(1)
+	KABI_RESERVE(2)
+	KABI_RESERVE(3)
+	KABI_RESERVE(4)
 };
 
 struct cgroup_base_stat {
@@ -482,6 +496,10 @@ struct cgroup {
 	/* Used to store internal freezer state */
 	struct cgroup_freezer_state freezer;
 
+	KABI_RESERVE(1)
+	KABI_RESERVE(2)
+	KABI_RESERVE(3)
+
 	/* ids of the ancestors at each level including self */
 	u64 ancestor_ids[];
 };
@@ -523,6 +541,11 @@ struct cgroup_root {
 
 	/* The name for this hierarchy - may be empty */
 	char name[MAX_CGROUP_ROOT_NAMELEN];
+
+	KABI_RESERVE(1)
+	KABI_RESERVE(2)
+	KABI_RESERVE(3)
+	KABI_RESERVE(4)
 };
 
 /*
@@ -618,6 +641,8 @@ struct cftype {
 	__poll_t (*poll)(struct kernfs_open_file *of,
 			 struct poll_table_struct *pt);
 
+	KABI_RESERVE(1)
+
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 	struct lock_class_key	lockdep_key;
 #endif
@@ -650,6 +675,10 @@ struct cgroup_subsys {
 	void (*release)(struct task_struct *task);
 	void (*bind)(struct cgroup_subsys_state *root_css);
 
+	KABI_RESERVE(1)
+	KABI_RESERVE(2)
+	KABI_RESERVE(3)
+	KABI_RESERVE(4)
 	bool early_init:1;
 
 	/*