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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 = RES_COUNTER_MAX;
21 counter->soft_limit = RES_COUNTER_MAX;
22 counter->parent = parent;
23}
24
25static u64 res_counter_uncharge_locked(struct res_counter *counter,
26 unsigned long val)
27{
28 if (WARN_ON(counter->usage < val))
29 val = counter->usage;
30
31 counter->usage -= val;
32 return counter->usage;
33}
34
35static int res_counter_charge_locked(struct res_counter *counter,
36 unsigned long val, bool force)
37{
38 int ret = 0;
39
40 if (counter->usage + val > counter->limit) {
41 counter->failcnt++;
42 ret = -ENOMEM;
43 if (!force)
44 return ret;
45 }
46
47 counter->usage += val;
48 if (counter->usage > counter->max_usage)
49 counter->max_usage = counter->usage;
50 return ret;
51}
52
53static int __res_counter_charge(struct res_counter *counter, unsigned long val,
54 struct res_counter **limit_fail_at, bool force)
55{
56 int ret, r;
57 unsigned long flags;
58 struct res_counter *c, *u;
59
60 r = ret = 0;
61 *limit_fail_at = NULL;
62 local_irq_save(flags);
63 for (c = counter; c != NULL; c = c->parent) {
64 spin_lock(&c->lock);
65 r = res_counter_charge_locked(c, val, force);
66 spin_unlock(&c->lock);
67 if (r < 0 && !ret) {
68 ret = r;
69 *limit_fail_at = c;
70 if (!force)
71 break;
72 }
73 }
74
75 if (ret < 0 && !force) {
76 for (u = counter; u != c; u = u->parent) {
77 spin_lock(&u->lock);
78 res_counter_uncharge_locked(u, val);
79 spin_unlock(&u->lock);
80 }
81 }
82 local_irq_restore(flags);
83
84 return ret;
85}
86
87int res_counter_charge(struct res_counter *counter, unsigned long val,
88 struct res_counter **limit_fail_at)
89{
90 return __res_counter_charge(counter, val, limit_fail_at, false);
91}
92
93int res_counter_charge_nofail(struct res_counter *counter, unsigned long val,
94 struct res_counter **limit_fail_at)
95{
96 return __res_counter_charge(counter, val, limit_fail_at, true);
97}
98
99u64 res_counter_uncharge_until(struct res_counter *counter,
100 struct res_counter *top,
101 unsigned long val)
102{
103 unsigned long flags;
104 struct res_counter *c;
105 u64 ret = 0;
106
107 local_irq_save(flags);
108 for (c = counter; c != top; c = c->parent) {
109 u64 r;
110 spin_lock(&c->lock);
111 r = res_counter_uncharge_locked(c, val);
112 if (c == counter)
113 ret = r;
114 spin_unlock(&c->lock);
115 }
116 local_irq_restore(flags);
117 return ret;
118}
119
120u64 res_counter_uncharge(struct res_counter *counter, unsigned long val)
121{
122 return res_counter_uncharge_until(counter, NULL, val);
123}
124
125static inline unsigned long long *
126res_counter_member(struct res_counter *counter, int member)
127{
128 switch (member) {
129 case RES_USAGE:
130 return &counter->usage;
131 case RES_MAX_USAGE:
132 return &counter->max_usage;
133 case RES_LIMIT:
134 return &counter->limit;
135 case RES_FAILCNT:
136 return &counter->failcnt;
137 case RES_SOFT_LIMIT:
138 return &counter->soft_limit;
139 };
140
141 BUG();
142 return NULL;
143}
144
145ssize_t res_counter_read(struct res_counter *counter, int member,
146 const char __user *userbuf, size_t nbytes, loff_t *pos,
147 int (*read_strategy)(unsigned long long val, char *st_buf))
148{
149 unsigned long long *val;
150 char buf[64], *s;
151
152 s = buf;
153 val = res_counter_member(counter, member);
154 if (read_strategy)
155 s += read_strategy(*val, s);
156 else
157 s += sprintf(s, "%llu\n", *val);
158 return simple_read_from_buffer((void __user *)userbuf, nbytes,
159 pos, buf, s - buf);
160}
161
162#if BITS_PER_LONG == 32
163u64 res_counter_read_u64(struct res_counter *counter, int member)
164{
165 unsigned long flags;
166 u64 ret;
167
168 spin_lock_irqsave(&counter->lock, flags);
169 ret = *res_counter_member(counter, member);
170 spin_unlock_irqrestore(&counter->lock, flags);
171
172 return ret;
173}
174#else
175u64 res_counter_read_u64(struct res_counter *counter, int member)
176{
177 return *res_counter_member(counter, member);
178}
179#endif
180
181int res_counter_memparse_write_strategy(const char *buf,
182 unsigned long long *resp)
183{
184 char *end;
185 unsigned long long res;
186
187
188 if (*buf == '-') {
189 int rc = kstrtoull(buf + 1, 10, &res);
190
191 if (rc)
192 return rc;
193 if (res != 1)
194 return -EINVAL;
195 *resp = RES_COUNTER_MAX;
196 return 0;
197 }
198
199 res = memparse(buf, &end);
200 if (*end != '\0')
201 return -EINVAL;
202
203 if (PAGE_ALIGN(res) >= res)
204 res = PAGE_ALIGN(res);
205 else
206 res = RES_COUNTER_MAX;
207
208 *resp = res;
209
210 return 0;
211}
212
