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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"
17#define MAX_NUM ULONG_MAX
18
19/* Miscellaneous res name, keep it in sync with enum misc_res_type */
20static const char *const misc_res_name[] = {
21#ifdef CONFIG_KVM_AMD_SEV
22 /* AMD SEV ASIDs resource */
23 "sev",
24 /* AMD SEV-ES ASIDs resource */
25 "sev_es",
26#endif
27};
28
29/* Root misc cgroup */
30static 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 */
40static unsigned long misc_res_capacity[MISC_CG_RES_TYPES];
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 */
51static 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 */
65static 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 */
77unsigned long misc_cg_res_total_usage(enum misc_res_type type)
78{
79 if (valid_type(type))
80 return atomic_long_read(&root_cg.res[type].usage);
81
82 return 0;
83}
84EXPORT_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 */
98int misc_cg_set_capacity(enum misc_res_type type, unsigned long capacity)
99{
100 if (!valid_type(type))
101 return -EINVAL;
102
103 WRITE_ONCE(misc_res_capacity[type], capacity);
104 return 0;
105}
106EXPORT_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 */
116static void misc_cg_cancel_charge(enum misc_res_type type, struct misc_cg *cg,
117 unsigned long amount)
118{
119 WARN_ONCE(atomic_long_add_negative(-amount, &cg->res[type].usage),
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 */
140int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
141 unsigned long amount)
142{
143 struct misc_cg *i, *j;
144 int ret;
145 struct misc_res *res;
146 int new_usage;
147
148 if (!(valid_type(type) && cg && READ_ONCE(misc_res_capacity[type])))
149 return -EINVAL;
150
151 if (!amount)
152 return 0;
153
154 for (i = cg; i; i = parent_misc(i)) {
155 res = &i->res[type];
156
157 new_usage = atomic_long_add_return(amount, &res->usage);
158 if (new_usage > READ_ONCE(res->max) ||
159 new_usage > READ_ONCE(misc_res_capacity[type])) {
160 ret = -EBUSY;
161 goto err_charge;
162 }
163 }
164 return 0;
165
166err_charge:
167 for (j = i; j; j = parent_misc(j)) {
168 atomic_long_inc(&j->res[type].events);
169 cgroup_file_notify(&j->events_file);
170 }
171
172 for (j = cg; j != i; j = parent_misc(j))
173 misc_cg_cancel_charge(type, j, amount);
174 misc_cg_cancel_charge(type, i, amount);
175 return ret;
176}
177EXPORT_SYMBOL_GPL(misc_cg_try_charge);
178
179/**
180 * misc_cg_uncharge() - Uncharge the misc cgroup.
181 * @type: Misc res type which was charged.
182 * @cg: Misc cgroup which will be uncharged.
183 * @amount: Charged amount.
184 *
185 * Context: Any context.
186 */
187void misc_cg_uncharge(enum misc_res_type type, struct misc_cg *cg,
188 unsigned long amount)
189{
190 struct misc_cg *i;
191
192 if (!(amount && valid_type(type) && cg))
193 return;
194
195 for (i = cg; i; i = parent_misc(i))
196 misc_cg_cancel_charge(type, i, amount);
197}
198EXPORT_SYMBOL_GPL(misc_cg_uncharge);
199
200/**
201 * misc_cg_max_show() - Show the misc cgroup max limit.
202 * @sf: Interface file
203 * @v: Arguments passed
204 *
205 * Context: Any context.
206 * Return: 0 to denote successful print.
207 */
208static int misc_cg_max_show(struct seq_file *sf, void *v)
209{
210 int i;
211 struct misc_cg *cg = css_misc(seq_css(sf));
212 unsigned long max;
213
214 for (i = 0; i < MISC_CG_RES_TYPES; i++) {
215 if (READ_ONCE(misc_res_capacity[i])) {
216 max = READ_ONCE(cg->res[i].max);
217 if (max == MAX_NUM)
218 seq_printf(sf, "%s max\n", misc_res_name[i]);
219 else
220 seq_printf(sf, "%s %lu\n", misc_res_name[i],
221 max);
222 }
223 }
224
225 return 0;
226}
227
228/**
229 * misc_cg_max_write() - Update the maximum limit of the cgroup.
230 * @of: Handler for the file.
231 * @buf: Data from the user. It should be either "max", 0, or a positive
232 * integer.
233 * @nbytes: Number of bytes of the data.
234 * @off: Offset in the file.
235 *
236 * User can pass data like:
237 * echo sev 23 > misc.max, OR
238 * echo sev max > misc.max
239 *
240 * Context: Any context.
241 * Return:
242 * * >= 0 - Number of bytes processed in the input.
243 * * -EINVAL - If buf is not valid.
244 * * -ERANGE - If number is bigger than the unsigned long capacity.
245 */
246static ssize_t misc_cg_max_write(struct kernfs_open_file *of, char *buf,
247 size_t nbytes, loff_t off)
248{
249 struct misc_cg *cg;
250 unsigned long max;
251 int ret = 0, i;
252 enum misc_res_type type = MISC_CG_RES_TYPES;
253 char *token;
254
255 buf = strstrip(buf);
256 token = strsep(&buf, " ");
257
258 if (!token || !buf)
259 return -EINVAL;
260
261 for (i = 0; i < MISC_CG_RES_TYPES; i++) {
262 if (!strcmp(misc_res_name[i], token)) {
263 type = i;
264 break;
265 }
266 }
267
268 if (type == MISC_CG_RES_TYPES)
269 return -EINVAL;
270
271 if (!strcmp(MAX_STR, buf)) {
272 max = MAX_NUM;
273 } else {
274 ret = kstrtoul(buf, 0, &max);
275 if (ret)
276 return ret;
277 }
278
279 cg = css_misc(of_css(of));
280
281 if (READ_ONCE(misc_res_capacity[type]))
282 WRITE_ONCE(cg->res[type].max, max);
283 else
284 ret = -EINVAL;
285
286 return ret ? ret : nbytes;
287}
288
289/**
290 * misc_cg_current_show() - Show the current usage of the misc cgroup.
291 * @sf: Interface file
292 * @v: Arguments passed
293 *
294 * Context: Any context.
295 * Return: 0 to denote successful print.
296 */
297static int misc_cg_current_show(struct seq_file *sf, void *v)
298{
299 int i;
300 unsigned long usage;
301 struct misc_cg *cg = css_misc(seq_css(sf));
302
303 for (i = 0; i < MISC_CG_RES_TYPES; i++) {
304 usage = atomic_long_read(&cg->res[i].usage);
305 if (READ_ONCE(misc_res_capacity[i]) || usage)
306 seq_printf(sf, "%s %lu\n", misc_res_name[i], usage);
307 }
308
309 return 0;
310}
311
312/**
313 * misc_cg_capacity_show() - Show the total capacity of misc res on the host.
314 * @sf: Interface file
315 * @v: Arguments passed
316 *
317 * Only present in the root cgroup directory.
318 *
319 * Context: Any context.
320 * Return: 0 to denote successful print.
321 */
322static int misc_cg_capacity_show(struct seq_file *sf, void *v)
323{
324 int i;
325 unsigned long cap;
326
327 for (i = 0; i < MISC_CG_RES_TYPES; i++) {
328 cap = READ_ONCE(misc_res_capacity[i]);
329 if (cap)
330 seq_printf(sf, "%s %lu\n", misc_res_name[i], cap);
331 }
332
333 return 0;
334}
335
336static int misc_events_show(struct seq_file *sf, void *v)
337{
338 struct misc_cg *cg = css_misc(seq_css(sf));
339 unsigned long events, i;
340
341 for (i = 0; i < MISC_CG_RES_TYPES; i++) {
342 events = atomic_long_read(&cg->res[i].events);
343 if (READ_ONCE(misc_res_capacity[i]) || events)
344 seq_printf(sf, "%s.max %lu\n", misc_res_name[i], events);
345 }
346 return 0;
347}
348
349/* Misc cgroup interface files */
350static struct cftype misc_cg_files[] = {
351 {
352 .name = "max",
353 .write = misc_cg_max_write,
354 .seq_show = misc_cg_max_show,
355 .flags = CFTYPE_NOT_ON_ROOT,
356 },
357 {
358 .name = "current",
359 .seq_show = misc_cg_current_show,
360 .flags = CFTYPE_NOT_ON_ROOT,
361 },
362 {
363 .name = "capacity",
364 .seq_show = misc_cg_capacity_show,
365 .flags = CFTYPE_ONLY_ON_ROOT,
366 },
367 {
368 .name = "events",
369 .flags = CFTYPE_NOT_ON_ROOT,
370 .file_offset = offsetof(struct misc_cg, events_file),
371 .seq_show = misc_events_show,
372 },
373 {}
374};
375
376/**
377 * misc_cg_alloc() - Allocate misc cgroup.
378 * @parent_css: Parent cgroup.
379 *
380 * Context: Process context.
381 * Return:
382 * * struct cgroup_subsys_state* - css of the allocated cgroup.
383 * * ERR_PTR(-ENOMEM) - No memory available to allocate.
384 */
385static struct cgroup_subsys_state *
386misc_cg_alloc(struct cgroup_subsys_state *parent_css)
387{
388 enum misc_res_type i;
389 struct misc_cg *cg;
390
391 if (!parent_css) {
392 cg = &root_cg;
393 } else {
394 cg = kzalloc(sizeof(*cg), GFP_KERNEL);
395 if (!cg)
396 return ERR_PTR(-ENOMEM);
397 }
398
399 for (i = 0; i < MISC_CG_RES_TYPES; i++) {
400 WRITE_ONCE(cg->res[i].max, MAX_NUM);
401 atomic_long_set(&cg->res[i].usage, 0);
402 }
403
404 return &cg->css;
405}
406
407/**
408 * misc_cg_free() - Free the misc cgroup.
409 * @css: cgroup subsys object.
410 *
411 * Context: Any context.
412 */
413static void misc_cg_free(struct cgroup_subsys_state *css)
414{
415 kfree(css_misc(css));
416}
417
418/* Cgroup controller callbacks */
419struct cgroup_subsys misc_cgrp_subsys = {
420 .css_alloc = misc_cg_alloc,
421 .css_free = misc_cg_free,
422 .legacy_cftypes = misc_cg_files,
423 .dfl_cftypes = misc_cg_files,
424};
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"
17#define MAX_NUM U64_MAX
18
19/* Miscellaneous res name, keep it in sync with enum misc_res_type */
20static const char *const misc_res_name[] = {
21#ifdef CONFIG_KVM_AMD_SEV
22 /* AMD SEV ASIDs resource */
23 "sev",
24 /* AMD SEV-ES ASIDs resource */
25 "sev_es",
26#endif
27};
28
29/* Root misc cgroup */
30static 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 */
40static u64 misc_res_capacity[MISC_CG_RES_TYPES];
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 */
51static 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 */
65static 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 */
77u64 misc_cg_res_total_usage(enum misc_res_type type)
78{
79 if (valid_type(type))
80 return atomic64_read(&root_cg.res[type].usage);
81
82 return 0;
83}
84EXPORT_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 */
98int misc_cg_set_capacity(enum misc_res_type type, u64 capacity)
99{
100 if (!valid_type(type))
101 return -EINVAL;
102
103 WRITE_ONCE(misc_res_capacity[type], capacity);
104 return 0;
105}
106EXPORT_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 */
116static void misc_cg_cancel_charge(enum misc_res_type type, struct misc_cg *cg,
117 u64 amount)
118{
119 WARN_ONCE(atomic64_add_negative(-amount, &cg->res[type].usage),
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 */
140int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
141{
142 struct misc_cg *i, *j;
143 int ret;
144 struct misc_res *res;
145 u64 new_usage;
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
156 new_usage = atomic64_add_return(amount, &res->usage);
157 if (new_usage > READ_ONCE(res->max) ||
158 new_usage > READ_ONCE(misc_res_capacity[type])) {
159 ret = -EBUSY;
160 goto err_charge;
161 }
162 }
163 return 0;
164
165err_charge:
166 for (j = i; j; j = parent_misc(j)) {
167 atomic64_inc(&j->res[type].events);
168 cgroup_file_notify(&j->events_file);
169 }
170
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}
176EXPORT_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 */
186void misc_cg_uncharge(enum misc_res_type type, struct misc_cg *cg, u64 amount)
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}
196EXPORT_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 */
206static 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));
210 u64 max;
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
218 seq_printf(sf, "%s %llu\n", misc_res_name[i],
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.
242 * * -ERANGE - If number is bigger than the u64 capacity.
243 */
244static 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;
248 u64 max;
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 {
272 ret = kstrtou64(buf, 0, &max);
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 */
295static int misc_cg_current_show(struct seq_file *sf, void *v)
296{
297 int i;
298 u64 usage;
299 struct misc_cg *cg = css_misc(seq_css(sf));
300
301 for (i = 0; i < MISC_CG_RES_TYPES; i++) {
302 usage = atomic64_read(&cg->res[i].usage);
303 if (READ_ONCE(misc_res_capacity[i]) || usage)
304 seq_printf(sf, "%s %llu\n", misc_res_name[i], usage);
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 */
320static int misc_cg_capacity_show(struct seq_file *sf, void *v)
321{
322 int i;
323 u64 cap;
324
325 for (i = 0; i < MISC_CG_RES_TYPES; i++) {
326 cap = READ_ONCE(misc_res_capacity[i]);
327 if (cap)
328 seq_printf(sf, "%s %llu\n", misc_res_name[i], cap);
329 }
330
331 return 0;
332}
333
334static int misc_events_show(struct seq_file *sf, void *v)
335{
336 struct misc_cg *cg = css_misc(seq_css(sf));
337 u64 events;
338 int i;
339
340 for (i = 0; i < MISC_CG_RES_TYPES; i++) {
341 events = atomic64_read(&cg->res[i].events);
342 if (READ_ONCE(misc_res_capacity[i]) || events)
343 seq_printf(sf, "%s.max %llu\n", misc_res_name[i], events);
344 }
345 return 0;
346}
347
348/* Misc cgroup interface files */
349static 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,
359 },
360 {
361 .name = "capacity",
362 .seq_show = misc_cg_capacity_show,
363 .flags = CFTYPE_ONLY_ON_ROOT,
364 },
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 },
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 */
383static struct cgroup_subsys_state *
384misc_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);
399 atomic64_set(&cg->res[i].usage, 0);
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 */
411static void misc_cg_free(struct cgroup_subsys_state *css)
412{
413 kfree(css_misc(css));
414}
415
416/* Cgroup controller callbacks */
417struct 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};