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e552b661 PE |
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_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 *res_counter_member(struct res_counter *counter, | |
63 | 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 | { | |
81 | unsigned long *val; | |
82 | char buf[64], *s; | |
83 | ||
84 | s = buf; | |
85 | val = res_counter_member(counter, member); | |
86 | s += sprintf(s, "%lu\n", *val); | |
87 | return simple_read_from_buffer((void __user *)userbuf, nbytes, | |
88 | pos, buf, s - buf); | |
89 | } | |
90 | ||
91 | ssize_t res_counter_write(struct res_counter *counter, int member, | |
92 | const char __user *userbuf, size_t nbytes, loff_t *pos) | |
93 | { | |
94 | int ret; | |
95 | char *buf, *end; | |
96 | unsigned long tmp, *val; | |
97 | ||
98 | buf = kmalloc(nbytes + 1, GFP_KERNEL); | |
99 | ret = -ENOMEM; | |
100 | if (buf == NULL) | |
101 | goto out; | |
102 | ||
103 | buf[nbytes] = '\0'; | |
104 | ret = -EFAULT; | |
105 | if (copy_from_user(buf, userbuf, nbytes)) | |
106 | goto out_free; | |
107 | ||
108 | ret = -EINVAL; | |
109 | tmp = simple_strtoul(buf, &end, 10); | |
110 | if (*end != '\0') | |
111 | goto out_free; | |
112 | ||
113 | val = res_counter_member(counter, member); | |
114 | *val = tmp; | |
115 | ret = nbytes; | |
116 | out_free: | |
117 | kfree(buf); | |
118 | out: | |
119 | return ret; | |
120 | } |