Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/core/netclassid_cgroup.c	Classid Cgroupfs Handling
 *
 * Authors:	Thomas Graf <tgraf@suug.ch>
 */
 
#include <linux/slab.h>
#include <linux/cgroup.h>
#include <linux/fdtable.h>
#include <linux/sched/task.h>
 
#include <net/cls_cgroup.h>
#include <net/sock.h>
 
static inline struct cgroup_cls_state *css_cls_state(struct cgroup_subsys_state *css)
{
<------>return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
}
 
struct cgroup_cls_state *task_cls_state(struct task_struct *p)
{
<------>return css_cls_state(task_css_check(p, net_cls_cgrp_id,
<------><------><------><------><------>    rcu_read_lock_bh_held()));
}
EXPORT_SYMBOL_GPL(task_cls_state);
 
static struct cgroup_subsys_state *
cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
{
<------>struct cgroup_cls_state *cs;
 
<------>cs = kzalloc(sizeof(*cs), GFP_KERNEL);
<------>if (!cs)
<------><------>return ERR_PTR(-ENOMEM);
 
<------>return &cs->css;
}
 
static int cgrp_css_online(struct cgroup_subsys_state *css)
{
<------>struct cgroup_cls_state *cs = css_cls_state(css);
<------>struct cgroup_cls_state *parent = css_cls_state(css->parent);
 
<------>if (parent)
<------><------>cs->classid = parent->classid;
 
<------>return 0;
}
 
static void cgrp_css_free(struct cgroup_subsys_state *css)
{
<------>kfree(css_cls_state(css));
}
 
/*
 * To avoid freezing of sockets creation for tasks with big number of threads
 * and opened sockets lets release file_lock every 1000 iterated descriptors.
 * New sockets will already have been created with new classid.
 */
 
struct update_classid_context {
<------>u32 classid;
<------>unsigned int batch;
};
 
#define UPDATE_CLASSID_BATCH 1000
 
static int update_classid_sock(const void *v, struct file *file, unsigned n)
{
<------>int err;
<------>struct update_classid_context *ctx = (void *)v;
<------>struct socket *sock = sock_from_file(file, &err);
 
<------>if (sock) {
<------><------>spin_lock(&cgroup_sk_update_lock);
<------><------>sock_cgroup_set_classid(&sock->sk->sk_cgrp_data, ctx->classid);
<------><------>spin_unlock(&cgroup_sk_update_lock);
<------>}
<------>if (--ctx->batch == 0) {
<------><------>ctx->batch = UPDATE_CLASSID_BATCH;
<------><------>return n + 1;
<------>}
<------>return 0;
}
 
static void update_classid_task(struct task_struct *p, u32 classid)
{
<------>struct update_classid_context ctx = {
<------><------>.classid = classid,
<------><------>.batch = UPDATE_CLASSID_BATCH
<------>};
<------>unsigned int fd = 0;
 
<------>do {
<------><------>task_lock(p);
<------><------>fd = iterate_fd(p->files, fd, update_classid_sock, &ctx);
<------><------>task_unlock(p);
<------><------>cond_resched();
<------>} while (fd);
}
 
static void cgrp_attach(struct cgroup_taskset *tset)
{
<------>struct cgroup_subsys_state *css;
<------>struct task_struct *p;
 
<------>cgroup_taskset_for_each(p, css, tset) {
<------><------>update_classid_task(p, css_cls_state(css)->classid);
<------>}
}
 
static u64 read_classid(struct cgroup_subsys_state *css, struct cftype *cft)
{
<------>return css_cls_state(css)->classid;
}
 
static int write_classid(struct cgroup_subsys_state *css, struct cftype *cft,
<------><------><------> u64 value)
{
<------>struct cgroup_cls_state *cs = css_cls_state(css);
<------>struct css_task_iter it;
<------>struct task_struct *p;
 
<------>cgroup_sk_alloc_disable();
 
<------>cs->classid = (u32)value;
 
<------>css_task_iter_start(css, 0, &it);
<------>while ((p = css_task_iter_next(&it)))
<------><------>update_classid_task(p, cs->classid);
<------>css_task_iter_end(&it);
 
<------>return 0;
}
 
static struct cftype ss_files[] = {
<------>{
<------><------>.name		= "classid",
<------><------>.read_u64	= read_classid,
<------><------>.write_u64	= write_classid,
<------>},
<------>{ }	/* terminate */
};
 
struct cgroup_subsys net_cls_cgrp_subsys = {
<------>.css_alloc		= cgrp_css_alloc,
<------>.css_online		= cgrp_css_online,
<------>.css_free		= cgrp_css_free,
<------>.attach			= cgrp_attach,
<------>.legacy_cftypes		= ss_files,
};