[linux-block.git] / net / core / netclassid_cgroup.c

// 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)
{
	struct update_classid_context *ctx = (void *)v;
	struct socket *sock = sock_from_file(file);

	if (sock)
		sock_cgroup_set_classid(&sock->sk->sk_cgrp_data, ctx->classid);
	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;

	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,
};
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
fe1217c4 DB	2	/*
	3	* net/core/netclassid_cgroup.c Classid Cgroupfs Handling
	4	*
fe1217c4 DB	5	* Authors: Thomas Graf <tgraf@suug.ch>
	6	*/
	7
fe1217c4 DB	8	#include <linux/slab.h>
	9	#include <linux/cgroup.h>
	10	#include <linux/fdtable.h>
f719ff9b IM	11	#include <linux/sched/task.h>
f719ff9b IM	12
fe1217c4 DB	13	#include <net/cls_cgroup.h>
	14	#include <net/sock.h>
	15
	16	static inline struct cgroup_cls_state css_cls_state(struct cgroup_subsys_state css)
	17	{
	18	return css ? container_of(css, struct cgroup_cls_state, css) : NULL;
	19	}
	20
	21	struct cgroup_cls_state task_cls_state(struct task_struct p)
	22	{
cc9f4daa KK	23	return css_cls_state(task_css_check(p, net_cls_cgrp_id,
cc9f4daa KK	24	rcu_read_lock_bh_held()));
fe1217c4 DB	25	}
	26	EXPORT_SYMBOL_GPL(task_cls_state);
	27
	28	static struct cgroup_subsys_state *
	29	cgrp_css_alloc(struct cgroup_subsys_state *parent_css)
	30	{
	31	struct cgroup_cls_state *cs;
	32
	33	cs = kzalloc(sizeof(*cs), GFP_KERNEL);
	34	if (!cs)
	35	return ERR_PTR(-ENOMEM);
	36
	37	return &cs->css;
	38	}
	39
	40	static int cgrp_css_online(struct cgroup_subsys_state *css)
	41	{
	42	struct cgroup_cls_state *cs = css_cls_state(css);
5c9d535b	43	struct cgroup_cls_state *parent = css_cls_state(css->parent);
fe1217c4 DB	44
	45	if (parent)
	46	cs->classid = parent->classid;
	47
	48	return 0;
	49	}
	50
	51	static void cgrp_css_free(struct cgroup_subsys_state *css)
	52	{
	53	kfree(css_cls_state(css));
	54	}
	55
018d26fc DY	56	/*
	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.
	60	*/
	61
	62	struct update_classid_context {
	63	u32 classid;
	64	unsigned int batch;
	65	};
	66
	67	#define UPDATE_CLASSID_BATCH 1000
	68
3b13758f	69	static int update_classid_sock(const void v, struct file file, unsigned n)
fe1217c4	70	{
018d26fc	71	struct update_classid_context ctx = (void )v;
dba4a925	72	struct socket *sock = sock_from_file(file);
fe1217c4	73
8520e224	74	if (sock)
018d26fc	75	sock_cgroup_set_classid(&sock->sk->sk_cgrp_data, ctx->classid);
018d26fc DY	76	if (--ctx->batch == 0) {
	77	ctx->batch = UPDATE_CLASSID_BATCH;
	78	return n + 1;
	79	}
fe1217c4 DB	80	return 0;
	81	}
	82
018d26fc DY	83	static void update_classid_task(struct task_struct *p, u32 classid)
	84	{
	85	struct update_classid_context ctx = {
	86	.classid = classid,
	87	.batch = UPDATE_CLASSID_BATCH
	88	};
	89	unsigned int fd = 0;
	90
	91	do {
	92	task_lock(p);
	93	fd = iterate_fd(p->files, fd, update_classid_sock, &ctx);
	94	task_unlock(p);
	95	cond_resched();
	96	} while (fd);
	97	}
	98
a05d4fd9	99	static void cgrp_attach(struct cgroup_taskset *tset)
fe1217c4	100	{
a05d4fd9	101	struct cgroup_subsys_state *css;
fe1217c4 DB	102	struct task_struct *p;
fe1217c4 DB	103
a05d4fd9	104	cgroup_taskset_for_each(p, css, tset) {
018d26fc	105	update_classid_task(p, css_cls_state(css)->classid);
fe1217c4 DB	106	}
	107	}
	108
	109	static u64 read_classid(struct cgroup_subsys_state css, struct cftype cft)
	110	{
	111	return css_cls_state(css)->classid;
	112	}
	113
	114	static int write_classid(struct cgroup_subsys_state css, struct cftype cft,
	115	u64 value)
	116	{
3b13758f	117	struct cgroup_cls_state *cs = css_cls_state(css);
a05d4fd9 TH	118	struct css_task_iter it;
a05d4fd9 TH	119	struct task_struct *p;
3b13758f NS	120
3b13758f NS	121	cs->classid = (u32)value;
fe1217c4	122
bc2fb7ed	123	css_task_iter_start(css, 0, &it);
526f3d96	124	while ((p = css_task_iter_next(&it)))
018d26fc	125	update_classid_task(p, cs->classid);
a05d4fd9 TH	126	css_task_iter_end(&it);
a05d4fd9 TH	127
fe1217c4 DB	128	return 0;
	129	}
	130
	131	static struct cftype ss_files[] = {
	132	{
	133	.name = "classid",
	134	.read_u64 = read_classid,
	135	.write_u64 = write_classid,
	136	},
	137	{ } /* terminate */
	138	};
	139
073219e9	140	struct cgroup_subsys net_cls_cgrp_subsys = {
fe1217c4 DB	141	.css_alloc = cgrp_css_alloc,
	142	.css_online = cgrp_css_online,
	143	.css_free = cgrp_css_free,
	144	.attach = cgrp_attach,
5577964e	145	.legacy_cftypes = ss_files,
fe1217c4	146	};