Merge tag 'upstream-3.7-rc1' of git://git.infradead.org/linux-ubifs
[linux-3.10.git] / kernel / res_counter.c
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
17 void 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
25 int res_counter_charge_locked(struct res_counter *counter, unsigned long val,
26                               bool force)
27 {
28         int ret = 0;
29
30         if (counter->usage + val > counter->limit) {
31                 counter->failcnt++;
32                 ret = -ENOMEM;
33                 if (!force)
34                         return ret;
35         }
36
37         counter->usage += val;
38         if (counter->usage > counter->max_usage)
39                 counter->max_usage = counter->usage;
40         return ret;
41 }
42
43 static int __res_counter_charge(struct res_counter *counter, unsigned long val,
44                                 struct res_counter **limit_fail_at, bool force)
45 {
46         int ret, r;
47         unsigned long flags;
48         struct res_counter *c, *u;
49
50         r = ret = 0;
51         *limit_fail_at = NULL;
52         local_irq_save(flags);
53         for (c = counter; c != NULL; c = c->parent) {
54                 spin_lock(&c->lock);
55                 r = res_counter_charge_locked(c, val, force);
56                 spin_unlock(&c->lock);
57                 if (r < 0 && !ret) {
58                         ret = r;
59                         *limit_fail_at = c;
60                         if (!force)
61                                 break;
62                 }
63         }
64
65         if (ret < 0 && !force) {
66                 for (u = counter; u != c; u = u->parent) {
67                         spin_lock(&u->lock);
68                         res_counter_uncharge_locked(u, val);
69                         spin_unlock(&u->lock);
70                 }
71         }
72         local_irq_restore(flags);
73
74         return ret;
75 }
76
77 int res_counter_charge(struct res_counter *counter, unsigned long val,
78                         struct res_counter **limit_fail_at)
79 {
80         return __res_counter_charge(counter, val, limit_fail_at, false);
81 }
82
83 int res_counter_charge_nofail(struct res_counter *counter, unsigned long val,
84                               struct res_counter **limit_fail_at)
85 {
86         return __res_counter_charge(counter, val, limit_fail_at, true);
87 }
88
89 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
90 {
91         if (WARN_ON(counter->usage < val))
92                 val = counter->usage;
93
94         counter->usage -= val;
95 }
96
97 void res_counter_uncharge_until(struct res_counter *counter,
98                                 struct res_counter *top,
99                                 unsigned long val)
100 {
101         unsigned long flags;
102         struct res_counter *c;
103
104         local_irq_save(flags);
105         for (c = counter; c != top; c = c->parent) {
106                 spin_lock(&c->lock);
107                 res_counter_uncharge_locked(c, val);
108                 spin_unlock(&c->lock);
109         }
110         local_irq_restore(flags);
111 }
112
113 void res_counter_uncharge(struct res_counter *counter, unsigned long val)
114 {
115         res_counter_uncharge_until(counter, NULL, val);
116 }
117
118 static inline unsigned long long *
119 res_counter_member(struct res_counter *counter, int member)
120 {
121         switch (member) {
122         case RES_USAGE:
123                 return &counter->usage;
124         case RES_MAX_USAGE:
125                 return &counter->max_usage;
126         case RES_LIMIT:
127                 return &counter->limit;
128         case RES_FAILCNT:
129                 return &counter->failcnt;
130         case RES_SOFT_LIMIT:
131                 return &counter->soft_limit;
132         };
133
134         BUG();
135         return NULL;
136 }
137
138 ssize_t res_counter_read(struct res_counter *counter, int member,
139                 const char __user *userbuf, size_t nbytes, loff_t *pos,
140                 int (*read_strategy)(unsigned long long val, char *st_buf))
141 {
142         unsigned long long *val;
143         char buf[64], *s;
144
145         s = buf;
146         val = res_counter_member(counter, member);
147         if (read_strategy)
148                 s += read_strategy(*val, s);
149         else
150                 s += sprintf(s, "%llu\n", *val);
151         return simple_read_from_buffer((void __user *)userbuf, nbytes,
152                         pos, buf, s - buf);
153 }
154
155 #if BITS_PER_LONG == 32
156 u64 res_counter_read_u64(struct res_counter *counter, int member)
157 {
158         unsigned long flags;
159         u64 ret;
160
161         spin_lock_irqsave(&counter->lock, flags);
162         ret = *res_counter_member(counter, member);
163         spin_unlock_irqrestore(&counter->lock, flags);
164
165         return ret;
166 }
167 #else
168 u64 res_counter_read_u64(struct res_counter *counter, int member)
169 {
170         return *res_counter_member(counter, member);
171 }
172 #endif
173
174 int res_counter_memparse_write_strategy(const char *buf,
175                                         unsigned long long *res)
176 {
177         char *end;
178
179         /* return RESOURCE_MAX(unlimited) if "-1" is specified */
180         if (*buf == '-') {
181                 *res = simple_strtoull(buf + 1, &end, 10);
182                 if (*res != 1 || *end != '\0')
183                         return -EINVAL;
184                 *res = RESOURCE_MAX;
185                 return 0;
186         }
187
188         *res = memparse(buf, &end);
189         if (*end != '\0')
190                 return -EINVAL;
191
192         *res = PAGE_ALIGN(*res);
193         return 0;
194 }
195
196 int res_counter_write(struct res_counter *counter, int member,
197                       const char *buf, write_strategy_fn write_strategy)
198 {
199         char *end;
200         unsigned long flags;
201         unsigned long long tmp, *val;
202
203         if (write_strategy) {
204                 if (write_strategy(buf, &tmp))
205                         return -EINVAL;
206         } else {
207                 tmp = simple_strtoull(buf, &end, 10);
208                 if (*end != '\0')
209                         return -EINVAL;
210         }
211         spin_lock_irqsave(&counter->lock, flags);
212         val = res_counter_member(counter, member);
213         *val = tmp;
214         spin_unlock_irqrestore(&counter->lock, flags);
215         return 0;
216 }