Memory Resource Controller use strstrip while parsing arguments
[linux-2.6.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
16 void res_counter_init(struct res_counter *counter)
17 {
18         spin_lock_init(&counter->lock);
19         counter->limit = (unsigned long long)LLONG_MAX;
20 }
21
22 int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
23 {
24         if (counter->usage + val > counter->limit) {
25                 counter->failcnt++;
26                 return -ENOMEM;
27         }
28
29         counter->usage += val;
30         return 0;
31 }
32
33 int res_counter_charge(struct res_counter *counter, unsigned long val)
34 {
35         int ret;
36         unsigned long flags;
37
38         spin_lock_irqsave(&counter->lock, flags);
39         ret = res_counter_charge_locked(counter, val);
40         spin_unlock_irqrestore(&counter->lock, flags);
41         return ret;
42 }
43
44 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
45 {
46         if (WARN_ON(counter->usage < val))
47                 val = counter->usage;
48
49         counter->usage -= val;
50 }
51
52 void res_counter_uncharge(struct res_counter *counter, unsigned long val)
53 {
54         unsigned long flags;
55
56         spin_lock_irqsave(&counter->lock, flags);
57         res_counter_uncharge_locked(counter, val);
58         spin_unlock_irqrestore(&counter->lock, flags);
59 }
60
61
62 static inline unsigned long long *
63 res_counter_member(struct res_counter *counter, int member)
64 {
65         switch (member) {
66         case RES_USAGE:
67                 return &counter->usage;
68         case RES_LIMIT:
69                 return &counter->limit;
70         case RES_FAILCNT:
71                 return &counter->failcnt;
72         };
73
74         BUG();
75         return NULL;
76 }
77
78 ssize_t res_counter_read(struct res_counter *counter, int member,
79                 const char __user *userbuf, size_t nbytes, loff_t *pos,
80                 int (*read_strategy)(unsigned long long val, char *st_buf))
81 {
82         unsigned long long *val;
83         char buf[64], *s;
84
85         s = buf;
86         val = res_counter_member(counter, member);
87         if (read_strategy)
88                 s += read_strategy(*val, s);
89         else
90                 s += sprintf(s, "%llu\n", *val);
91         return simple_read_from_buffer((void __user *)userbuf, nbytes,
92                         pos, buf, s - buf);
93 }
94
95 ssize_t res_counter_write(struct res_counter *counter, int member,
96                 const char __user *userbuf, size_t nbytes, loff_t *pos,
97                 int (*write_strategy)(char *st_buf, unsigned long long *val))
98 {
99         int ret;
100         char *buf, *end;
101         unsigned long flags;
102         unsigned long long tmp, *val;
103
104         buf = kmalloc(nbytes + 1, GFP_KERNEL);
105         ret = -ENOMEM;
106         if (buf == NULL)
107                 goto out;
108
109         buf[nbytes] = '\0';
110         ret = -EFAULT;
111         if (copy_from_user(buf, userbuf, nbytes))
112                 goto out_free;
113
114         ret = -EINVAL;
115
116         strstrip(buf);
117         if (write_strategy) {
118                 if (write_strategy(buf, &tmp)) {
119                         goto out_free;
120                 }
121         } else {
122                 tmp = simple_strtoull(buf, &end, 10);
123                 if (*end != '\0')
124                         goto out_free;
125         }
126         spin_lock_irqsave(&counter->lock, flags);
127         val = res_counter_member(counter, member);
128         *val = tmp;
129         spin_unlock_irqrestore(&counter->lock, flags);
130         ret = nbytes;
131 out_free:
132         kfree(buf);
133 out:
134         return ret;
135 }