1/*
2 * resource cgroups
3 *
4 * Copyright 2007 OpenVZ SWsoft Inc
5 *
6 * Author: Pavel Emelianov <xemul@openvz.org>
7 *
8 */
9
10#include <linux/types.h>
11#include <linux/parser.h>
12#include <linux/fs.h>
13#include <linux/res_counter.h>
14#include <linux/uaccess.h>
15#include <linux/mm.h>
16
17void res_counter_init(struct res_counter *counter, struct res_counter *parent)
18{
19	spin_lock_init(&counter->lock);
20	counter->limit = RESOURCE_MAX;
21	counter->soft_limit = RESOURCE_MAX;
22	counter->parent = parent;
23}
24
25int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
26{
27	if (counter->usage + val > counter->limit) {
28		counter->failcnt++;
29		return -ENOMEM;
30	}
31
32	counter->usage += val;
33	if (counter->usage > counter->max_usage)
34		counter->max_usage = counter->usage;
35	return 0;
36}
37
38int res_counter_charge(struct res_counter *counter, unsigned long val,
39			struct res_counter **limit_fail_at)
40{
41	int ret;
42	unsigned long flags;
43	struct res_counter *c, *u;
44
45	*limit_fail_at = NULL;
46	local_irq_save(flags);
47	for (c = counter; c != NULL; c = c->parent) {
48		spin_lock(&c->lock);
49		ret = res_counter_charge_locked(c, val);
50		spin_unlock(&c->lock);
51		if (ret < 0) {
52			*limit_fail_at = c;
53			goto undo;
54		}
55	}
56	ret = 0;
57	goto done;
58undo:
59	for (u = counter; u != c; u = u->parent) {
60		spin_lock(&u->lock);
61		res_counter_uncharge_locked(u, val);
62		spin_unlock(&u->lock);
63	}
64done:
65	local_irq_restore(flags);
66	return ret;
67}
68
69void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
70{
71	if (WARN_ON(counter->usage < val))
72		val = counter->usage;
73
74	counter->usage -= val;
75}
76
77void res_counter_uncharge(struct res_counter *counter, unsigned long val)
78{
79	unsigned long flags;
80	struct res_counter *c;
81
82	local_irq_save(flags);
83	for (c = counter; c != NULL; c = c->parent) {
84		spin_lock(&c->lock);
85		res_counter_uncharge_locked(c, val);
86		spin_unlock(&c->lock);
87	}
88	local_irq_restore(flags);
89}
90
91
92static inline unsigned long long *
93res_counter_member(struct res_counter *counter, int member)
94{
95	switch (member) {
96	case RES_USAGE:
97		return &counter->usage;
98	case RES_MAX_USAGE:
99		return &counter->max_usage;
100	case RES_LIMIT:
101		return &counter->limit;
102	case RES_FAILCNT:
103		return &counter->failcnt;
104	case RES_SOFT_LIMIT:
105		return &counter->soft_limit;
106	};
107
108	BUG();
109	return NULL;
110}
111
112ssize_t res_counter_read(struct res_counter *counter, int member,
113		const char __user *userbuf, size_t nbytes, loff_t *pos,
114		int (*read_strategy)(unsigned long long val, char *st_buf))
115{
116	unsigned long long *val;
117	char buf[64], *s;
118
119	s = buf;
120	val = res_counter_member(counter, member);
121	if (read_strategy)
122		s += read_strategy(*val, s);
123	else
124		s += sprintf(s, "%llu\n", *val);
125	return simple_read_from_buffer((void __user *)userbuf, nbytes,
126			pos, buf, s - buf);
127}
128
129u64 res_counter_read_u64(struct res_counter *counter, int member)
130{
131	return *res_counter_member(counter, member);
132}
133
134int res_counter_memparse_write_strategy(const char *buf,
135					unsigned long long *res)
136{
137	char *end;
138
139	/* return RESOURCE_MAX(unlimited) if "-1" is specified */
140	if (*buf == '-') {
141		*res = simple_strtoull(buf + 1, &end, 10);
142		if (*res != 1 || *end != '\0')
143			return -EINVAL;
144		*res = RESOURCE_MAX;
145		return 0;
146	}
147
148	*res = memparse((char *)buf, &end);
149	if (*end != '\0')
150		return -EINVAL;
151
152	*res = PAGE_ALIGN(*res);
153	return 0;
154}
155
156int res_counter_write(struct res_counter *counter, int member,
157		      const char *buf, write_strategy_fn write_strategy)
158{
159	char *end;
160	unsigned long flags;
161	unsigned long long tmp, *val;
162
163	if (write_strategy) {
164		if (write_strategy(buf, &tmp))
165			return -EINVAL;
166	} else {
167		tmp = simple_strtoull(buf, &end, 10);
168		if (*end != '\0')
169			return -EINVAL;
170	}
171	spin_lock_irqsave(&counter->lock, flags);
172	val = res_counter_member(counter, member);
173	*val = tmp;
174	spin_unlock_irqrestore(&counter->lock, flags);
175	return 0;
176}
177