1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * net/core/netclassid_cgroup.c Classid Cgroupfs Handling
5 * Authors: Thomas Graf <tgraf@suug.ch>
8 #include <linux/slab.h>
9 #include <linux/cgroup.h>
10 #include <linux/fdtable.h>
11 #include <linux/sched/task.h>
13 #include <net/cls_cgroup.h>
16 static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
18 return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
21 struct cgroup_cls_state *task_cls_state(struct task_struct *p)
23 return css_cls_state(task_css_check(p, net_cls_cgrp_id,
24 rcu_read_lock_bh_held()));
26 EXPORT_SYMBOL_GPL(task_cls_state);
28 static struct cgroup_subsys_state *
29 cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
31 struct cgroup_cls_state *cs;
33 cs = kzalloc(sizeof(*cs), GFP_KERNEL);
35 return ERR_PTR(-ENOMEM);
40 static int cgrp_css_online(struct cgroup_subsys_state *css)
42 struct cgroup_cls_state *cs = css_cls_state(css);
43 struct cgroup_cls_state *parent = css_cls_state(css->parent);
46 cs->classid = parent->classid;
51 static void cgrp_css_free(struct cgroup_subsys_state *css)
53 kfree(css_cls_state(css));
57 * To avoid freezing of sockets creation for tasks with big number of threads
58 * and opened sockets lets release file_lock every 1000 iterated descriptors.
59 * New sockets will already have been created with new classid.
62 struct update_classid_context {
67 #define UPDATE_CLASSID_BATCH 1000
69 static int update_classid_sock(const void *v, struct file *file, unsigned n)
72 struct update_classid_context *ctx = (void *)v;
73 struct socket *sock = sock_from_file(file, &err);
76 spin_lock(&cgroup_sk_update_lock);
77 sock_cgroup_set_classid(&sock->sk->sk_cgrp_data, ctx->classid);
78 spin_unlock(&cgroup_sk_update_lock);
80 if (--ctx->batch == 0) {
81 ctx->batch = UPDATE_CLASSID_BATCH;
87 static void update_classid_task(struct task_struct *p, u32 classid)
89 struct update_classid_context ctx = {
91 .batch = UPDATE_CLASSID_BATCH
97 fd = iterate_fd(p->files, fd, update_classid_sock, &ctx);
103 static void cgrp_attach(struct cgroup_taskset *tset)
105 struct cgroup_subsys_state *css;
106 struct task_struct *p;
108 cgroup_taskset_for_each(p, css, tset) {
109 update_classid_task(p, css_cls_state(css)->classid);
113 static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
115 return css_cls_state(css)->classid;
118 static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
121 struct cgroup_cls_state *cs = css_cls_state(css);
122 struct css_task_iter it;
123 struct task_struct *p;
125 cgroup_sk_alloc_disable();
127 cs->classid = (u32)value;
129 css_task_iter_start(css, 0, &it);
130 while ((p = css_task_iter_next(&it)))
131 update_classid_task(p, cs->classid);
132 css_task_iter_end(&it);
137 static struct cftype ss_files[] = {
140 .read_u64 = read_classid,
141 .write_u64 = write_classid,
146 struct cgroup_subsys net_cls_cgrp_subsys = {
147 .css_alloc = cgrp_css_alloc,
148 .css_online = cgrp_css_online,
149 .css_free = cgrp_css_free,
150 .attach = cgrp_attach,
151 .legacy_cftypes = ss_files,