[linux-block.git] / kernel / cgroup / misc.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Miscellaneous cgroup controller
 *
 * Copyright 2020 Google LLC
 * Author: Vipin Sharma <vipinsh@google.com>
 */

#include <linux/limits.h>
#include <linux/cgroup.h>
#include <linux/errno.h>
#include <linux/atomic.h>
#include <linux/slab.h>
#include <linux/misc_cgroup.h>

#define MAX_STR "max"
#define MAX_NUM U64_MAX

/* Miscellaneous res name, keep it in sync with enum misc_res_type */
static const char *const misc_res_name[] = {
#ifdef CONFIG_KVM_AMD_SEV
	/* AMD SEV ASIDs resource */
	"sev",
	/* AMD SEV-ES ASIDs resource */
	"sev_es",
#endif
};

/* Root misc cgroup */
static struct misc_cg root_cg;

/*
 * Miscellaneous resources capacity for the entire machine. 0 capacity means
 * resource is not initialized or not present in the host.
 *
 * root_cg.max and capacity are independent of each other. root_cg.max can be
 * more than the actual capacity. We are using Limits resource distribution
 * model of cgroup for miscellaneous controller.
 */
static u64 misc_res_capacity[MISC_CG_RES_TYPES];

/**
 * parent_misc() - Get the parent of the passed misc cgroup.
 * @cgroup: cgroup whose parent needs to be fetched.
 *
 * Context: Any context.
 * Return:
 * * struct misc_cg* - Parent of the @cgroup.
 * * %NULL - If @cgroup is null or the passed cgroup does not have a parent.
 */
static struct misc_cg *parent_misc(struct misc_cg *cgroup)
{
	return cgroup ? css_misc(cgroup->css.parent) : NULL;
}

/**
 * valid_type() - Check if @type is valid or not.
 * @type: misc res type.
 *
 * Context: Any context.
 * Return:
 * * true - If valid type.
 * * false - If not valid type.
 */
static inline bool valid_type(enum misc_res_type type)
{
	return type >= 0 && type < MISC_CG_RES_TYPES;
}

/**
 * misc_cg_res_total_usage() - Get the current total usage of the resource.
 * @type: misc res type.
 *
 * Context: Any context.
 * Return: Current total usage of the resource.
 */
u64 misc_cg_res_total_usage(enum misc_res_type type)
{
	if (valid_type(type))
		return atomic64_read(&root_cg.res[type].usage);

	return 0;
}
EXPORT_SYMBOL_GPL(misc_cg_res_total_usage);

/**
 * misc_cg_set_capacity() - Set the capacity of the misc cgroup res.
 * @type: Type of the misc res.
 * @capacity: Supported capacity of the misc res on the host.
 *
 * If capacity is 0 then the charging a misc cgroup fails for that type.
 *
 * Context: Any context.
 * Return:
 * * %0 - Successfully registered the capacity.
 * * %-EINVAL - If @type is invalid.
 */
int misc_cg_set_capacity(enum misc_res_type type, u64 capacity)
{
	if (!valid_type(type))
		return -EINVAL;

	WRITE_ONCE(misc_res_capacity[type], capacity);
	return 0;
}
EXPORT_SYMBOL_GPL(misc_cg_set_capacity);

/**
 * misc_cg_cancel_charge() - Cancel the charge from the misc cgroup.
 * @type: Misc res type in misc cg to cancel the charge from.
 * @cg: Misc cgroup to cancel charge from.
 * @amount: Amount to cancel.
 *
 * Context: Any context.
 */
static void misc_cg_cancel_charge(enum misc_res_type type, struct misc_cg *cg,
				  u64 amount)
{
	WARN_ONCE(atomic64_add_negative(-amount, &cg->res[type].usage),
		  "misc cgroup resource %s became less than 0",
		  misc_res_name[type]);
}

/**
 * misc_cg_try_charge() - Try charging the misc cgroup.
 * @type: Misc res type to charge.
 * @cg: Misc cgroup which will be charged.
 * @amount: Amount to charge.
 *
 * Charge @amount to the misc cgroup. Caller must use the same cgroup during
 * the uncharge call.
 *
 * Context: Any context.
 * Return:
 * * %0 - If successfully charged.
 * * -EINVAL - If @type is invalid or misc res has 0 capacity.
 * * -EBUSY - If max limit will be crossed or total usage will be more than the
 *	      capacity.
 */
int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
{
	struct misc_cg *i, *j;
	int ret;
	struct misc_res *res;
	u64 new_usage;

	if (!(valid_type(type) && cg && READ_ONCE(misc_res_capacity[type])))
		return -EINVAL;

	if (!amount)
		return 0;

	for (i = cg; i; i = parent_misc(i)) {
		res = &i->res[type];

		new_usage = atomic64_add_return(amount, &res->usage);
		if (new_usage > READ_ONCE(res->max) ||
		    new_usage > READ_ONCE(misc_res_capacity[type])) {
			ret = -EBUSY;
			goto err_charge;
		}
	}
	return 0;

err_charge:
	for (j = i; j; j = parent_misc(j)) {
		atomic64_inc(&j->res[type].events);
		cgroup_file_notify(&j->events_file);
	}

	for (j = cg; j != i; j = parent_misc(j))
		misc_cg_cancel_charge(type, j, amount);
	misc_cg_cancel_charge(type, i, amount);
	return ret;
}
EXPORT_SYMBOL_GPL(misc_cg_try_charge);

/**
 * misc_cg_uncharge() - Uncharge the misc cgroup.
 * @type: Misc res type which was charged.
 * @cg: Misc cgroup which will be uncharged.
 * @amount: Charged amount.
 *
 * Context: Any context.
 */
void misc_cg_uncharge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
{
	struct misc_cg *i;

	if (!(amount && valid_type(type) && cg))
		return;

	for (i = cg; i; i = parent_misc(i))
		misc_cg_cancel_charge(type, i, amount);
}
EXPORT_SYMBOL_GPL(misc_cg_uncharge);

/**
 * misc_cg_max_show() - Show the misc cgroup max limit.
 * @sf: Interface file
 * @v: Arguments passed
 *
 * Context: Any context.
 * Return: 0 to denote successful print.
 */
static int misc_cg_max_show(struct seq_file *sf, void *v)
{
	int i;
	struct misc_cg *cg = css_misc(seq_css(sf));
	u64 max;

	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
		if (READ_ONCE(misc_res_capacity[i])) {
			max = READ_ONCE(cg->res[i].max);
			if (max == MAX_NUM)
				seq_printf(sf, "%s max\n", misc_res_name[i]);
			else
				seq_printf(sf, "%s %llu\n", misc_res_name[i],
					   max);
		}
	}

	return 0;
}

/**
 * misc_cg_max_write() - Update the maximum limit of the cgroup.
 * @of: Handler for the file.
 * @buf: Data from the user. It should be either "max", 0, or a positive
 *	 integer.
 * @nbytes: Number of bytes of the data.
 * @off: Offset in the file.
 *
 * User can pass data like:
 * echo sev 23 > misc.max, OR
 * echo sev max > misc.max
 *
 * Context: Any context.
 * Return:
 * * >= 0 - Number of bytes processed in the input.
 * * -EINVAL - If buf is not valid.
 * * -ERANGE - If number is bigger than the u64 capacity.
 */
static ssize_t misc_cg_max_write(struct kernfs_open_file *of, char *buf,
				 size_t nbytes, loff_t off)
{
	struct misc_cg *cg;
	u64 max;
	int ret = 0, i;
	enum misc_res_type type = MISC_CG_RES_TYPES;
	char *token;

	buf = strstrip(buf);
	token = strsep(&buf, " ");

	if (!token || !buf)
		return -EINVAL;

	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
		if (!strcmp(misc_res_name[i], token)) {
			type = i;
			break;
		}
	}

	if (type == MISC_CG_RES_TYPES)
		return -EINVAL;

	if (!strcmp(MAX_STR, buf)) {
		max = MAX_NUM;
	} else {
		ret = kstrtou64(buf, 0, &max);
		if (ret)
			return ret;
	}

	cg = css_misc(of_css(of));

	if (READ_ONCE(misc_res_capacity[type]))
		WRITE_ONCE(cg->res[type].max, max);
	else
		ret = -EINVAL;

	return ret ? ret : nbytes;
}

/**
 * misc_cg_current_show() - Show the current usage of the misc cgroup.
 * @sf: Interface file
 * @v: Arguments passed
 *
 * Context: Any context.
 * Return: 0 to denote successful print.
 */
static int misc_cg_current_show(struct seq_file *sf, void *v)
{
	int i;
	u64 usage;
	struct misc_cg *cg = css_misc(seq_css(sf));

	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
		usage = atomic64_read(&cg->res[i].usage);
		if (READ_ONCE(misc_res_capacity[i]) || usage)
			seq_printf(sf, "%s %llu\n", misc_res_name[i], usage);
	}

	return 0;
}

/**
 * misc_cg_capacity_show() - Show the total capacity of misc res on the host.
 * @sf: Interface file
 * @v: Arguments passed
 *
 * Only present in the root cgroup directory.
 *
 * Context: Any context.
 * Return: 0 to denote successful print.
 */
static int misc_cg_capacity_show(struct seq_file *sf, void *v)
{
	int i;
	u64 cap;

	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
		cap = READ_ONCE(misc_res_capacity[i]);
		if (cap)
			seq_printf(sf, "%s %llu\n", misc_res_name[i], cap);
	}

	return 0;
}

static int misc_events_show(struct seq_file *sf, void *v)
{
	struct misc_cg *cg = css_misc(seq_css(sf));
	u64 events;
	int i;

	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
		events = atomic64_read(&cg->res[i].events);
		if (READ_ONCE(misc_res_capacity[i]) || events)
			seq_printf(sf, "%s.max %llu\n", misc_res_name[i], events);
	}
	return 0;
}

/* Misc cgroup interface files */
static struct cftype misc_cg_files[] = {
	{
		.name = "max",
		.write = misc_cg_max_write,
		.seq_show = misc_cg_max_show,
		.flags = CFTYPE_NOT_ON_ROOT,
	},
	{
		.name = "current",
		.seq_show = misc_cg_current_show,
	},
	{
		.name = "capacity",
		.seq_show = misc_cg_capacity_show,
		.flags = CFTYPE_ONLY_ON_ROOT,
	},
	{
		.name = "events",
		.flags = CFTYPE_NOT_ON_ROOT,
		.file_offset = offsetof(struct misc_cg, events_file),
		.seq_show = misc_events_show,
	},
	{}
};

/**
 * misc_cg_alloc() - Allocate misc cgroup.
 * @parent_css: Parent cgroup.
 *
 * Context: Process context.
 * Return:
 * * struct cgroup_subsys_state* - css of the allocated cgroup.
 * * ERR_PTR(-ENOMEM) - No memory available to allocate.
 */
static struct cgroup_subsys_state *
misc_cg_alloc(struct cgroup_subsys_state *parent_css)
{
	enum misc_res_type i;
	struct misc_cg *cg;

	if (!parent_css) {
		cg = &root_cg;
	} else {
		cg = kzalloc(sizeof(*cg), GFP_KERNEL);
		if (!cg)
			return ERR_PTR(-ENOMEM);
	}

	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
		WRITE_ONCE(cg->res[i].max, MAX_NUM);
		atomic64_set(&cg->res[i].usage, 0);
	}

	return &cg->css;
}

/**
 * misc_cg_free() - Free the misc cgroup.
 * @css: cgroup subsys object.
 *
 * Context: Any context.
 */
static void misc_cg_free(struct cgroup_subsys_state *css)
{
	kfree(css_misc(css));
}

/* Cgroup controller callbacks */
struct cgroup_subsys misc_cgrp_subsys = {
	.css_alloc = misc_cg_alloc,
	.css_free = misc_cg_free,
	.legacy_cftypes = misc_cg_files,
	.dfl_cftypes = misc_cg_files,
};
Commit	Line	Data
a72232ea VS	1	// SPDX-License-Identifier: GPL-2.0
	2	/*
	3	* Miscellaneous cgroup controller
	4	*
	5	* Copyright 2020 Google LLC
	6	* Author: Vipin Sharma <vipinsh@google.com>
	7	*/
	8
	9	#include <linux/limits.h>
	10	#include <linux/cgroup.h>
	11	#include <linux/errno.h>
	12	#include <linux/atomic.h>
	13	#include <linux/slab.h>
	14	#include <linux/misc_cgroup.h>
	15
	16	#define MAX_STR "max"
32bf85c6	17	#define MAX_NUM U64_MAX
a72232ea VS	18
	19	/* Miscellaneous res name, keep it in sync with enum misc_res_type */
	20	static const char *const misc_res_name[] = {
7aef27f0 VS	21	#ifdef CONFIG_KVM_AMD_SEV
	22	/* AMD SEV ASIDs resource */
	23	"sev",
	24	/* AMD SEV-ES ASIDs resource */
	25	"sev_es",
	26	#endif
a72232ea VS	27	};
	28
	29	/* Root misc cgroup */
	30	static struct misc_cg root_cg;
	31
	32	/*
	33	* Miscellaneous resources capacity for the entire machine. 0 capacity means
	34	* resource is not initialized or not present in the host.
	35	*
	36	* root_cg.max and capacity are independent of each other. root_cg.max can be
	37	* more than the actual capacity. We are using Limits resource distribution
	38	* model of cgroup for miscellaneous controller.
	39	*/
32bf85c6	40	static u64 misc_res_capacity[MISC_CG_RES_TYPES];
a72232ea VS	41
	42	/**
	43	* parent_misc() - Get the parent of the passed misc cgroup.
	44	* @cgroup: cgroup whose parent needs to be fetched.
	45	*
	46	* Context: Any context.
	47	* Return:
	48	* * struct misc_cg* - Parent of the @cgroup.
	49	* * %NULL - If @cgroup is null or the passed cgroup does not have a parent.
	50	*/
	51	static struct misc_cg parent_misc(struct misc_cg cgroup)
	52	{
	53	return cgroup ? css_misc(cgroup->css.parent) : NULL;
	54	}
	55
	56	/**
	57	* valid_type() - Check if @type is valid or not.
	58	* @type: misc res type.
	59	*
	60	* Context: Any context.
	61	* Return:
	62	* * true - If valid type.
	63	* * false - If not valid type.
	64	*/
	65	static inline bool valid_type(enum misc_res_type type)
	66	{
	67	return type >= 0 && type < MISC_CG_RES_TYPES;
	68	}
	69
	70	/**
	71	* misc_cg_res_total_usage() - Get the current total usage of the resource.
	72	* @type: misc res type.
	73	*
	74	* Context: Any context.
	75	* Return: Current total usage of the resource.
	76	*/
32bf85c6	77	u64 misc_cg_res_total_usage(enum misc_res_type type)
a72232ea VS	78	{
a72232ea VS	79	if (valid_type(type))
32bf85c6	80	return atomic64_read(&root_cg.res[type].usage);
a72232ea VS	81
	82	return 0;
	83	}
	84	EXPORT_SYMBOL_GPL(misc_cg_res_total_usage);
	85
	86	/**
	87	* misc_cg_set_capacity() - Set the capacity of the misc cgroup res.
	88	* @type: Type of the misc res.
	89	* @capacity: Supported capacity of the misc res on the host.
	90	*
	91	* If capacity is 0 then the charging a misc cgroup fails for that type.
	92	*
	93	* Context: Any context.
	94	* Return:
	95	* * %0 - Successfully registered the capacity.
	96	* * %-EINVAL - If @type is invalid.
	97	*/
32bf85c6	98	int misc_cg_set_capacity(enum misc_res_type type, u64 capacity)
a72232ea VS	99	{
	100	if (!valid_type(type))
	101	return -EINVAL;
	102
	103	WRITE_ONCE(misc_res_capacity[type], capacity);
	104	return 0;
	105	}
	106	EXPORT_SYMBOL_GPL(misc_cg_set_capacity);
	107
	108	/**
	109	* misc_cg_cancel_charge() - Cancel the charge from the misc cgroup.
	110	* @type: Misc res type in misc cg to cancel the charge from.
	111	* @cg: Misc cgroup to cancel charge from.
	112	* @amount: Amount to cancel.
	113	*
	114	* Context: Any context.
	115	*/
	116	static void misc_cg_cancel_charge(enum misc_res_type type, struct misc_cg *cg,
32bf85c6	117	u64 amount)
a72232ea	118	{
32bf85c6	119	WARN_ONCE(atomic64_add_negative(-amount, &cg->res[type].usage),
a72232ea VS	120	"misc cgroup resource %s became less than 0",
	121	misc_res_name[type]);
	122	}
	123
	124	/**
	125	* misc_cg_try_charge() - Try charging the misc cgroup.
	126	* @type: Misc res type to charge.
	127	* @cg: Misc cgroup which will be charged.
	128	* @amount: Amount to charge.
	129	*
	130	* Charge @amount to the misc cgroup. Caller must use the same cgroup during
	131	* the uncharge call.
	132	*
	133	* Context: Any context.
	134	* Return:
	135	* * %0 - If successfully charged.
	136	* * -EINVAL - If @type is invalid or misc res has 0 capacity.
	137	* * -EBUSY - If max limit will be crossed or total usage will be more than the
	138	* capacity.
	139	*/
32bf85c6	140	int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
a72232ea VS	141	{
	142	struct misc_cg i, j;
	143	int ret;
	144	struct misc_res *res;
714e08cc	145	u64 new_usage;
a72232ea VS	146
	147	if (!(valid_type(type) && cg && READ_ONCE(misc_res_capacity[type])))
	148	return -EINVAL;
	149
	150	if (!amount)
	151	return 0;
	152
	153	for (i = cg; i; i = parent_misc(i)) {
	154	res = &i->res[type];
	155
32bf85c6	156	new_usage = atomic64_add_return(amount, &res->usage);
a72232ea VS	157	if (new_usage > READ_ONCE(res->max) \|\|
a72232ea VS	158	new_usage > READ_ONCE(misc_res_capacity[type])) {
a72232ea VS	159	ret = -EBUSY;
	160	goto err_charge;
	161	}
	162	}
	163	return 0;
	164
	165	err_charge:
f279294b	166	for (j = i; j; j = parent_misc(j)) {
32bf85c6	167	atomic64_inc(&j->res[type].events);
f279294b CX	168	cgroup_file_notify(&j->events_file);
	169	}
	170
a72232ea VS	171	for (j = cg; j != i; j = parent_misc(j))
	172	misc_cg_cancel_charge(type, j, amount);
	173	misc_cg_cancel_charge(type, i, amount);
	174	return ret;
	175	}
	176	EXPORT_SYMBOL_GPL(misc_cg_try_charge);
	177
	178	/**
	179	* misc_cg_uncharge() - Uncharge the misc cgroup.
	180	* @type: Misc res type which was charged.
	181	* @cg: Misc cgroup which will be uncharged.
	182	* @amount: Charged amount.
	183	*
	184	* Context: Any context.
	185	*/
32bf85c6	186	void misc_cg_uncharge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
a72232ea VS	187	{
	188	struct misc_cg *i;
	189
	190	if (!(amount && valid_type(type) && cg))
	191	return;
	192
	193	for (i = cg; i; i = parent_misc(i))
	194	misc_cg_cancel_charge(type, i, amount);
	195	}
	196	EXPORT_SYMBOL_GPL(misc_cg_uncharge);
	197
	198	/**
	199	* misc_cg_max_show() - Show the misc cgroup max limit.
	200	* @sf: Interface file
	201	* @v: Arguments passed
	202	*
	203	* Context: Any context.
	204	* Return: 0 to denote successful print.
	205	*/
	206	static int misc_cg_max_show(struct seq_file sf, void v)
	207	{
	208	int i;
	209	struct misc_cg *cg = css_misc(seq_css(sf));
32bf85c6	210	u64 max;
a72232ea VS	211
	212	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
	213	if (READ_ONCE(misc_res_capacity[i])) {
	214	max = READ_ONCE(cg->res[i].max);
	215	if (max == MAX_NUM)
	216	seq_printf(sf, "%s max\n", misc_res_name[i]);
	217	else
32bf85c6	218	seq_printf(sf, "%s %llu\n", misc_res_name[i],
a72232ea VS	219	max);
	220	}
	221	}
	222
	223	return 0;
	224	}
	225
	226	/**
	227	* misc_cg_max_write() - Update the maximum limit of the cgroup.
	228	* @of: Handler for the file.
	229	* @buf: Data from the user. It should be either "max", 0, or a positive
	230	* integer.
	231	* @nbytes: Number of bytes of the data.
	232	* @off: Offset in the file.
	233	*
	234	* User can pass data like:
	235	* echo sev 23 > misc.max, OR
	236	* echo sev max > misc.max
	237	*
	238	* Context: Any context.
	239	* Return:
	240	* * >= 0 - Number of bytes processed in the input.
	241	* * -EINVAL - If buf is not valid.
32bf85c6	242	* * -ERANGE - If number is bigger than the u64 capacity.
a72232ea VS	243	*/
	244	static ssize_t misc_cg_max_write(struct kernfs_open_file of, char buf,
	245	size_t nbytes, loff_t off)
	246	{
	247	struct misc_cg *cg;
32bf85c6	248	u64 max;
a72232ea VS	249	int ret = 0, i;
	250	enum misc_res_type type = MISC_CG_RES_TYPES;
	251	char *token;
	252
	253	buf = strstrip(buf);
	254	token = strsep(&buf, " ");
	255
	256	if (!token \|\| !buf)
	257	return -EINVAL;
	258
	259	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
	260	if (!strcmp(misc_res_name[i], token)) {
	261	type = i;
	262	break;
	263	}
	264	}
	265
	266	if (type == MISC_CG_RES_TYPES)
	267	return -EINVAL;
	268
	269	if (!strcmp(MAX_STR, buf)) {
	270	max = MAX_NUM;
	271	} else {
32bf85c6	272	ret = kstrtou64(buf, 0, &max);
a72232ea VS	273	if (ret)
	274	return ret;
	275	}
	276
	277	cg = css_misc(of_css(of));
	278
	279	if (READ_ONCE(misc_res_capacity[type]))
	280	WRITE_ONCE(cg->res[type].max, max);
	281	else
	282	ret = -EINVAL;
	283
	284	return ret ? ret : nbytes;
	285	}
	286
	287	/**
	288	* misc_cg_current_show() - Show the current usage of the misc cgroup.
	289	* @sf: Interface file
	290	* @v: Arguments passed
	291	*
	292	* Context: Any context.
	293	* Return: 0 to denote successful print.
	294	*/
	295	static int misc_cg_current_show(struct seq_file sf, void v)
	296	{
	297	int i;
32bf85c6	298	u64 usage;
a72232ea VS	299	struct misc_cg *cg = css_misc(seq_css(sf));
	300
	301	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
32bf85c6	302	usage = atomic64_read(&cg->res[i].usage);
a72232ea	303	if (READ_ONCE(misc_res_capacity[i]) \|\| usage)
32bf85c6	304	seq_printf(sf, "%s %llu\n", misc_res_name[i], usage);
a72232ea VS	305	}
	306
	307	return 0;
	308	}
	309
	310	/**
	311	* misc_cg_capacity_show() - Show the total capacity of misc res on the host.
	312	* @sf: Interface file
	313	* @v: Arguments passed
	314	*
	315	* Only present in the root cgroup directory.
	316	*
	317	* Context: Any context.
	318	* Return: 0 to denote successful print.
	319	*/
	320	static int misc_cg_capacity_show(struct seq_file sf, void v)
	321	{
	322	int i;
32bf85c6	323	u64 cap;
a72232ea VS	324
	325	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
	326	cap = READ_ONCE(misc_res_capacity[i]);
	327	if (cap)
32bf85c6	328	seq_printf(sf, "%s %llu\n", misc_res_name[i], cap);
a72232ea VS	329	}
	330
	331	return 0;
	332	}
	333
f279294b CX	334	static int misc_events_show(struct seq_file sf, void v)
	335	{
	336	struct misc_cg *cg = css_misc(seq_css(sf));
32bf85c6 HH	337	u64 events;
32bf85c6 HH	338	int i;
f279294b CX	339
f279294b CX	340	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
32bf85c6	341	events = atomic64_read(&cg->res[i].events);
f279294b	342	if (READ_ONCE(misc_res_capacity[i]) \|\| events)
32bf85c6	343	seq_printf(sf, "%s.max %llu\n", misc_res_name[i], events);
f279294b CX	344	}
	345	return 0;
	346	}
	347
a72232ea VS	348	/* Misc cgroup interface files */
	349	static struct cftype misc_cg_files[] = {
	350	{
	351	.name = "max",
	352	.write = misc_cg_max_write,
	353	.seq_show = misc_cg_max_show,
	354	.flags = CFTYPE_NOT_ON_ROOT,
	355	},
	356	{
	357	.name = "current",
	358	.seq_show = misc_cg_current_show,
a72232ea VS	359	},
	360	{
	361	.name = "capacity",
	362	.seq_show = misc_cg_capacity_show,
	363	.flags = CFTYPE_ONLY_ON_ROOT,
	364	},
f279294b CX	365	{
	366	.name = "events",
	367	.flags = CFTYPE_NOT_ON_ROOT,
	368	.file_offset = offsetof(struct misc_cg, events_file),
	369	.seq_show = misc_events_show,
	370	},
a72232ea VS	371	{}
	372	};
	373
	374	/**
	375	* misc_cg_alloc() - Allocate misc cgroup.
	376	* @parent_css: Parent cgroup.
	377	*
	378	* Context: Process context.
	379	* Return:
	380	* * struct cgroup_subsys_state* - css of the allocated cgroup.
	381	* * ERR_PTR(-ENOMEM) - No memory available to allocate.
	382	*/
	383	static struct cgroup_subsys_state *
	384	misc_cg_alloc(struct cgroup_subsys_state *parent_css)
	385	{
	386	enum misc_res_type i;
	387	struct misc_cg *cg;
	388
	389	if (!parent_css) {
	390	cg = &root_cg;
	391	} else {
	392	cg = kzalloc(sizeof(*cg), GFP_KERNEL);
	393	if (!cg)
	394	return ERR_PTR(-ENOMEM);
	395	}
	396
	397	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
	398	WRITE_ONCE(cg->res[i].max, MAX_NUM);
32bf85c6	399	atomic64_set(&cg->res[i].usage, 0);
a72232ea VS	400	}
	401
	402	return &cg->css;
	403	}
	404
	405	/**
	406	* misc_cg_free() - Free the misc cgroup.
	407	* @css: cgroup subsys object.
	408	*
	409	* Context: Any context.
	410	*/
	411	static void misc_cg_free(struct cgroup_subsys_state *css)
	412	{
	413	kfree(css_misc(css));
	414	}
	415
	416	/* Cgroup controller callbacks */
	417	struct cgroup_subsys misc_cgrp_subsys = {
	418	.css_alloc = misc_cg_alloc,
	419	.css_free = misc_cg_free,
	420	.legacy_cftypes = misc_cg_files,
	421	.dfl_cftypes = misc_cg_files,
	422	};