[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
#ifdef CONFIG_INTEL_TDX_HOST
	/* Intel TDX HKIDs resource */
	"tdx",
#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_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]);
}

static void misc_cg_update_watermark(struct misc_res *res, u64 new_usage)
{
	u64 old;

	while (true) {
		old = atomic64_read(&res->watermark);
		if (new_usage <= old)
			break;
		if (atomic64_cmpxchg(&res->watermark, old, new_usage) == old)
			break;
	}
}

static void misc_cg_event(enum misc_res_type type, struct misc_cg *cg)
{
	atomic64_inc(&cg->res[type].events_local);
	cgroup_file_notify(&cg->events_local_file);

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

/**
 * 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;
		}
		misc_cg_update_watermark(res, new_usage);
	}
	return 0;

err_charge:
	misc_cg_event(type, i);

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

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

	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, bool local)
{
	struct misc_cg *cg = css_misc(seq_css(sf));
	u64 events;
	int i;

	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
		if (local)
			events = atomic64_read(&cg->res[i].events_local);
		else
			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;
}

static int misc_events_show(struct seq_file *sf, void *v)
{
	return __misc_events_show(sf, false);
}

static int misc_events_local_show(struct seq_file *sf, void *v)
{
	return __misc_events_show(sf, true);
}

/* 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 = "peak",
		.seq_show = misc_cg_peak_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,
	},
	{
		.name = "events.local",
		.flags = CFTYPE_NOT_ON_ROOT,
		.file_offset = offsetof(struct misc_cg, events_local_file),
		.seq_show = misc_events_local_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
7c035bea ZH	27	#ifdef CONFIG_INTEL_TDX_HOST
	28	/* Intel TDX HKIDs resource */
	29	"tdx",
	30	#endif
a72232ea VS	31	};
	32
	33	/* Root misc cgroup */
	34	static struct misc_cg root_cg;
	35
	36	/*
	37	* Miscellaneous resources capacity for the entire machine. 0 capacity means
	38	* resource is not initialized or not present in the host.
	39	*
	40	* root_cg.max and capacity are independent of each other. root_cg.max can be
	41	* more than the actual capacity. We are using Limits resource distribution
	42	* model of cgroup for miscellaneous controller.
	43	*/
32bf85c6	44	static u64 misc_res_capacity[MISC_CG_RES_TYPES];
a72232ea VS	45
	46	/**
	47	* parent_misc() - Get the parent of the passed misc cgroup.
	48	* @cgroup: cgroup whose parent needs to be fetched.
	49	*
	50	* Context: Any context.
	51	* Return:
	52	* * struct misc_cg* - Parent of the @cgroup.
	53	* * %NULL - If @cgroup is null or the passed cgroup does not have a parent.
	54	*/
	55	static struct misc_cg parent_misc(struct misc_cg cgroup)
	56	{
	57	return cgroup ? css_misc(cgroup->css.parent) : NULL;
	58	}
	59
	60	/**
	61	* valid_type() - Check if @type is valid or not.
	62	* @type: misc res type.
	63	*
	64	* Context: Any context.
	65	* Return:
	66	* * true - If valid type.
	67	* * false - If not valid type.
	68	*/
	69	static inline bool valid_type(enum misc_res_type type)
	70	{
	71	return type >= 0 && type < MISC_CG_RES_TYPES;
	72	}
	73
a72232ea VS	74	/**
	75	* misc_cg_set_capacity() - Set the capacity of the misc cgroup res.
	76	* @type: Type of the misc res.
	77	* @capacity: Supported capacity of the misc res on the host.
	78	*
	79	* If capacity is 0 then the charging a misc cgroup fails for that type.
	80	*
	81	* Context: Any context.
	82	* Return:
	83	* * %0 - Successfully registered the capacity.
	84	* * %-EINVAL - If @type is invalid.
	85	*/
32bf85c6	86	int misc_cg_set_capacity(enum misc_res_type type, u64 capacity)
a72232ea VS	87	{
	88	if (!valid_type(type))
	89	return -EINVAL;
	90
	91	WRITE_ONCE(misc_res_capacity[type], capacity);
	92	return 0;
	93	}
	94	EXPORT_SYMBOL_GPL(misc_cg_set_capacity);
	95
	96	/**
	97	* misc_cg_cancel_charge() - Cancel the charge from the misc cgroup.
	98	* @type: Misc res type in misc cg to cancel the charge from.
	99	* @cg: Misc cgroup to cancel charge from.
	100	* @amount: Amount to cancel.
	101	*
	102	* Context: Any context.
	103	*/
	104	static void misc_cg_cancel_charge(enum misc_res_type type, struct misc_cg *cg,
32bf85c6	105	u64 amount)
a72232ea	106	{
32bf85c6	107	WARN_ONCE(atomic64_add_negative(-amount, &cg->res[type].usage),
a72232ea VS	108	"misc cgroup resource %s became less than 0",
	109	misc_res_name[type]);
	110	}
	111
1028f391 XJ	112	static void misc_cg_update_watermark(struct misc_res *res, u64 new_usage)
	113	{
	114	u64 old;
	115
	116	while (true) {
	117	old = atomic64_read(&res->watermark);
	118	if (new_usage <= old)
	119	break;
	120	if (atomic64_cmpxchg(&res->watermark, old, new_usage) == old)
	121	break;
	122	}
	123	}
	124
6a26f9c6 XJ	125	static void misc_cg_event(enum misc_res_type type, struct misc_cg *cg)
	126	{
	127	atomic64_inc(&cg->res[type].events_local);
	128	cgroup_file_notify(&cg->events_local_file);
	129
	130	for (; parent_misc(cg); cg = parent_misc(cg)) {
	131	atomic64_inc(&cg->res[type].events);
	132	cgroup_file_notify(&cg->events_file);
	133	}
	134	}
	135
a72232ea VS	136	/**
	137	* misc_cg_try_charge() - Try charging the misc cgroup.
	138	* @type: Misc res type to charge.
	139	* @cg: Misc cgroup which will be charged.
	140	* @amount: Amount to charge.
	141	*
	142	* Charge @amount to the misc cgroup. Caller must use the same cgroup during
	143	* the uncharge call.
	144	*
	145	* Context: Any context.
	146	* Return:
	147	* * %0 - If successfully charged.
	148	* * -EINVAL - If @type is invalid or misc res has 0 capacity.
	149	* * -EBUSY - If max limit will be crossed or total usage will be more than the
	150	* capacity.
	151	*/
32bf85c6	152	int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
a72232ea VS	153	{
	154	struct misc_cg i, j;
	155	int ret;
	156	struct misc_res *res;
714e08cc	157	u64 new_usage;
a72232ea VS	158
	159	if (!(valid_type(type) && cg && READ_ONCE(misc_res_capacity[type])))
	160	return -EINVAL;
	161
	162	if (!amount)
	163	return 0;
	164
	165	for (i = cg; i; i = parent_misc(i)) {
	166	res = &i->res[type];
	167
32bf85c6	168	new_usage = atomic64_add_return(amount, &res->usage);
a72232ea VS	169	if (new_usage > READ_ONCE(res->max) \|\|
a72232ea VS	170	new_usage > READ_ONCE(misc_res_capacity[type])) {
a72232ea VS	171	ret = -EBUSY;
	172	goto err_charge;
	173	}
1028f391	174	misc_cg_update_watermark(res, new_usage);
a72232ea VS	175	}
	176	return 0;
	177
	178	err_charge:
6a26f9c6	179	misc_cg_event(type, i);
f279294b	180
a72232ea VS	181	for (j = cg; j != i; j = parent_misc(j))
	182	misc_cg_cancel_charge(type, j, amount);
	183	misc_cg_cancel_charge(type, i, amount);
	184	return ret;
	185	}
	186	EXPORT_SYMBOL_GPL(misc_cg_try_charge);
	187
	188	/**
	189	* misc_cg_uncharge() - Uncharge the misc cgroup.
	190	* @type: Misc res type which was charged.
	191	* @cg: Misc cgroup which will be uncharged.
	192	* @amount: Charged amount.
	193	*
	194	* Context: Any context.
	195	*/
32bf85c6	196	void misc_cg_uncharge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
a72232ea VS	197	{
	198	struct misc_cg *i;
	199
	200	if (!(amount && valid_type(type) && cg))
	201	return;
	202
	203	for (i = cg; i; i = parent_misc(i))
	204	misc_cg_cancel_charge(type, i, amount);
	205	}
	206	EXPORT_SYMBOL_GPL(misc_cg_uncharge);
	207
	208	/**
	209	* misc_cg_max_show() - Show the misc cgroup max limit.
	210	* @sf: Interface file
	211	* @v: Arguments passed
	212	*
	213	* Context: Any context.
	214	* Return: 0 to denote successful print.
	215	*/
	216	static int misc_cg_max_show(struct seq_file sf, void v)
	217	{
	218	int i;
	219	struct misc_cg *cg = css_misc(seq_css(sf));
32bf85c6	220	u64 max;
a72232ea VS	221
	222	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
	223	if (READ_ONCE(misc_res_capacity[i])) {
	224	max = READ_ONCE(cg->res[i].max);
	225	if (max == MAX_NUM)
	226	seq_printf(sf, "%s max\n", misc_res_name[i]);
	227	else
32bf85c6	228	seq_printf(sf, "%s %llu\n", misc_res_name[i],
a72232ea VS	229	max);
	230	}
	231	}
	232
	233	return 0;
	234	}
	235
	236	/**
	237	* misc_cg_max_write() - Update the maximum limit of the cgroup.
	238	* @of: Handler for the file.
	239	* @buf: Data from the user. It should be either "max", 0, or a positive
	240	* integer.
	241	* @nbytes: Number of bytes of the data.
	242	* @off: Offset in the file.
	243	*
	244	* User can pass data like:
	245	* echo sev 23 > misc.max, OR
	246	* echo sev max > misc.max
	247	*
	248	* Context: Any context.
	249	* Return:
	250	* * >= 0 - Number of bytes processed in the input.
	251	* * -EINVAL - If buf is not valid.
32bf85c6	252	* * -ERANGE - If number is bigger than the u64 capacity.
a72232ea VS	253	*/
	254	static ssize_t misc_cg_max_write(struct kernfs_open_file of, char buf,
	255	size_t nbytes, loff_t off)
	256	{
	257	struct misc_cg *cg;
32bf85c6	258	u64 max;
a72232ea VS	259	int ret = 0, i;
	260	enum misc_res_type type = MISC_CG_RES_TYPES;
	261	char *token;
	262
	263	buf = strstrip(buf);
	264	token = strsep(&buf, " ");
	265
	266	if (!token \|\| !buf)
	267	return -EINVAL;
	268
	269	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
	270	if (!strcmp(misc_res_name[i], token)) {
	271	type = i;
	272	break;
	273	}
	274	}
	275
	276	if (type == MISC_CG_RES_TYPES)
	277	return -EINVAL;
	278
	279	if (!strcmp(MAX_STR, buf)) {
	280	max = MAX_NUM;
	281	} else {
32bf85c6	282	ret = kstrtou64(buf, 0, &max);
a72232ea VS	283	if (ret)
	284	return ret;
	285	}
	286
	287	cg = css_misc(of_css(of));
	288
	289	if (READ_ONCE(misc_res_capacity[type]))
	290	WRITE_ONCE(cg->res[type].max, max);
	291	else
	292	ret = -EINVAL;
	293
	294	return ret ? ret : nbytes;
	295	}
	296
	297	/**
	298	* misc_cg_current_show() - Show the current usage of the misc cgroup.
	299	* @sf: Interface file
	300	* @v: Arguments passed
	301	*
	302	* Context: Any context.
	303	* Return: 0 to denote successful print.
	304	*/
	305	static int misc_cg_current_show(struct seq_file sf, void v)
	306	{
	307	int i;
32bf85c6	308	u64 usage;
a72232ea VS	309	struct misc_cg *cg = css_misc(seq_css(sf));
	310
	311	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
32bf85c6	312	usage = atomic64_read(&cg->res[i].usage);
a72232ea	313	if (READ_ONCE(misc_res_capacity[i]) \|\| usage)
32bf85c6	314	seq_printf(sf, "%s %llu\n", misc_res_name[i], usage);
a72232ea VS	315	}
	316
	317	return 0;
	318	}
	319
1028f391 XJ	320	/**
	321	* misc_cg_peak_show() - Show the peak usage of the misc cgroup.
	322	* @sf: Interface file
	323	* @v: Arguments passed
	324	*
	325	* Context: Any context.
	326	* Return: 0 to denote successful print.
	327	*/
	328	static int misc_cg_peak_show(struct seq_file sf, void v)
	329	{
	330	int i;
	331	u64 watermark;
	332	struct misc_cg *cg = css_misc(seq_css(sf));
	333
	334	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
	335	watermark = atomic64_read(&cg->res[i].watermark);
	336	if (READ_ONCE(misc_res_capacity[i]) \|\| watermark)
	337	seq_printf(sf, "%s %llu\n", misc_res_name[i], watermark);
	338	}
	339
	340	return 0;
	341	}
	342
a72232ea VS	343	/**
	344	* misc_cg_capacity_show() - Show the total capacity of misc res on the host.
	345	* @sf: Interface file
	346	* @v: Arguments passed
	347	*
	348	* Only present in the root cgroup directory.
	349	*
	350	* Context: Any context.
	351	* Return: 0 to denote successful print.
	352	*/
	353	static int misc_cg_capacity_show(struct seq_file sf, void v)
	354	{
	355	int i;
32bf85c6	356	u64 cap;
a72232ea VS	357
	358	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
	359	cap = READ_ONCE(misc_res_capacity[i]);
	360	if (cap)
32bf85c6	361	seq_printf(sf, "%s %llu\n", misc_res_name[i], cap);
a72232ea VS	362	}
	363
	364	return 0;
	365	}
	366
6a26f9c6	367	static int __misc_events_show(struct seq_file *sf, bool local)
f279294b CX	368	{
f279294b CX	369	struct misc_cg *cg = css_misc(seq_css(sf));
32bf85c6 HH	370	u64 events;
32bf85c6 HH	371	int i;
f279294b CX	372
f279294b CX	373	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
6a26f9c6 XJ	374	if (local)
	375	events = atomic64_read(&cg->res[i].events_local);
	376	else
	377	events = atomic64_read(&cg->res[i].events);
f279294b	378	if (READ_ONCE(misc_res_capacity[i]) \|\| events)
32bf85c6	379	seq_printf(sf, "%s.max %llu\n", misc_res_name[i], events);
f279294b CX	380	}
	381	return 0;
	382	}
	383
6a26f9c6 XJ	384	static int misc_events_show(struct seq_file sf, void v)
	385	{
	386	return __misc_events_show(sf, false);
	387	}
	388
	389	static int misc_events_local_show(struct seq_file sf, void v)
	390	{
	391	return __misc_events_show(sf, true);
	392	}
	393
a72232ea VS	394	/* Misc cgroup interface files */
	395	static struct cftype misc_cg_files[] = {
	396	{
	397	.name = "max",
	398	.write = misc_cg_max_write,
	399	.seq_show = misc_cg_max_show,
	400	.flags = CFTYPE_NOT_ON_ROOT,
	401	},
	402	{
	403	.name = "current",
	404	.seq_show = misc_cg_current_show,
a72232ea	405	},
1028f391 XJ	406	{
	407	.name = "peak",
	408	.seq_show = misc_cg_peak_show,
	409	},
a72232ea VS	410	{
	411	.name = "capacity",
	412	.seq_show = misc_cg_capacity_show,
	413	.flags = CFTYPE_ONLY_ON_ROOT,
	414	},
f279294b CX	415	{
	416	.name = "events",
	417	.flags = CFTYPE_NOT_ON_ROOT,
	418	.file_offset = offsetof(struct misc_cg, events_file),
	419	.seq_show = misc_events_show,
	420	},
6a26f9c6 XJ	421	{
	422	.name = "events.local",
	423	.flags = CFTYPE_NOT_ON_ROOT,
	424	.file_offset = offsetof(struct misc_cg, events_local_file),
	425	.seq_show = misc_events_local_show,
	426	},
a72232ea VS	427	{}
	428	};
	429
	430	/**
	431	* misc_cg_alloc() - Allocate misc cgroup.
	432	* @parent_css: Parent cgroup.
	433	*
	434	* Context: Process context.
	435	* Return:
	436	* * struct cgroup_subsys_state* - css of the allocated cgroup.
	437	* * ERR_PTR(-ENOMEM) - No memory available to allocate.
	438	*/
	439	static struct cgroup_subsys_state *
	440	misc_cg_alloc(struct cgroup_subsys_state *parent_css)
	441	{
	442	enum misc_res_type i;
	443	struct misc_cg *cg;
	444
	445	if (!parent_css) {
	446	cg = &root_cg;
	447	} else {
	448	cg = kzalloc(sizeof(*cg), GFP_KERNEL);
	449	if (!cg)
	450	return ERR_PTR(-ENOMEM);
	451	}
	452
	453	for (i = 0; i < MISC_CG_RES_TYPES; i++) {
	454	WRITE_ONCE(cg->res[i].max, MAX_NUM);
32bf85c6	455	atomic64_set(&cg->res[i].usage, 0);
a72232ea VS	456	}
	457
	458	return &cg->css;
	459	}
	460
	461	/**
	462	* misc_cg_free() - Free the misc cgroup.
	463	* @css: cgroup subsys object.
	464	*
	465	* Context: Any context.
	466	*/
	467	static void misc_cg_free(struct cgroup_subsys_state *css)
	468	{
	469	kfree(css_misc(css));
	470	}
	471
	472	/* Cgroup controller callbacks */
	473	struct cgroup_subsys misc_cgrp_subsys = {
	474	.css_alloc = misc_cg_alloc,
	475	.css_free = misc_cg_free,
	476	.legacy_cftypes = misc_cg_files,
	477	.dfl_cftypes = misc_cg_files,
	478	};