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6ff1cb35 AM |
1 | #include <linux/kernel.h> |
2 | #include <linux/init.h> | |
3 | #include <linux/random.h> | |
4 | #include <linux/stat.h> | |
5 | #include <linux/types.h> | |
6 | #include <linux/fs.h> | |
7 | #include <linux/module.h> | |
f4f154fd | 8 | #include <linux/interrupt.h> |
6ff1cb35 AM |
9 | #include <linux/fault-inject.h> |
10 | ||
11 | /* | |
12 | * setup_fault_attr() is a helper function for various __setup handlers, so it | |
13 | * returns 0 on error, because that is what __setup handlers do. | |
14 | */ | |
15 | int __init setup_fault_attr(struct fault_attr *attr, char *str) | |
16 | { | |
17 | unsigned long probability; | |
18 | unsigned long interval; | |
19 | int times; | |
20 | int space; | |
21 | ||
22 | /* "<interval>,<probability>,<space>,<times>" */ | |
23 | if (sscanf(str, "%lu,%lu,%d,%d", | |
24 | &interval, &probability, &space, ×) < 4) { | |
25 | printk(KERN_WARNING | |
26 | "FAULT_INJECTION: failed to parse arguments\n"); | |
27 | return 0; | |
28 | } | |
29 | ||
30 | attr->probability = probability; | |
31 | attr->interval = interval; | |
32 | atomic_set(&attr->times, times); | |
33 | atomic_set(&attr->space, space); | |
34 | ||
35 | return 1; | |
36 | } | |
37 | ||
38 | static void fail_dump(struct fault_attr *attr) | |
39 | { | |
40 | if (attr->verbose > 0) | |
41 | printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure\n"); | |
42 | if (attr->verbose > 1) | |
43 | dump_stack(); | |
44 | } | |
45 | ||
46 | #define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0) | |
47 | ||
f4f154fd AM |
48 | static int fail_task(struct fault_attr *attr, struct task_struct *task) |
49 | { | |
50 | return !in_interrupt() && task->make_it_fail; | |
51 | } | |
52 | ||
6ff1cb35 AM |
53 | /* |
54 | * This code is stolen from failmalloc-1.0 | |
55 | * http://www.nongnu.org/failmalloc/ | |
56 | */ | |
57 | ||
58 | int should_fail(struct fault_attr *attr, ssize_t size) | |
59 | { | |
f4f154fd AM |
60 | if (attr->task_filter && !fail_task(attr, current)) |
61 | return 0; | |
62 | ||
6ff1cb35 AM |
63 | if (atomic_read(&attr->times) == 0) |
64 | return 0; | |
65 | ||
66 | if (atomic_read(&attr->space) > size) { | |
67 | atomic_sub(size, &attr->space); | |
68 | return 0; | |
69 | } | |
70 | ||
71 | if (attr->interval > 1) { | |
72 | attr->count++; | |
73 | if (attr->count % attr->interval) | |
74 | return 0; | |
75 | } | |
76 | ||
77 | if (attr->probability > random32() % 100) | |
78 | goto fail; | |
79 | ||
80 | return 0; | |
81 | ||
82 | fail: | |
83 | fail_dump(attr); | |
84 | ||
85 | if (atomic_read(&attr->times) != -1) | |
86 | atomic_dec_not_zero(&attr->times); | |
87 | ||
88 | return 1; | |
89 | } | |
90 | ||
91 | #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS | |
92 | ||
93 | static void debugfs_ul_set(void *data, u64 val) | |
94 | { | |
95 | *(unsigned long *)data = val; | |
96 | } | |
97 | ||
98 | static u64 debugfs_ul_get(void *data) | |
99 | { | |
100 | return *(unsigned long *)data; | |
101 | } | |
102 | ||
103 | DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n"); | |
104 | ||
105 | static struct dentry *debugfs_create_ul(const char *name, mode_t mode, | |
106 | struct dentry *parent, unsigned long *value) | |
107 | { | |
108 | return debugfs_create_file(name, mode, parent, value, &fops_ul); | |
109 | } | |
110 | ||
111 | static void debugfs_atomic_t_set(void *data, u64 val) | |
112 | { | |
113 | atomic_set((atomic_t *)data, val); | |
114 | } | |
115 | ||
116 | static u64 debugfs_atomic_t_get(void *data) | |
117 | { | |
118 | return atomic_read((atomic_t *)data); | |
119 | } | |
120 | ||
121 | DEFINE_SIMPLE_ATTRIBUTE(fops_atomic_t, debugfs_atomic_t_get, | |
122 | debugfs_atomic_t_set, "%lld\n"); | |
123 | ||
124 | static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode, | |
125 | struct dentry *parent, atomic_t *value) | |
126 | { | |
127 | return debugfs_create_file(name, mode, parent, value, &fops_atomic_t); | |
128 | } | |
129 | ||
130 | void cleanup_fault_attr_dentries(struct fault_attr *attr) | |
131 | { | |
132 | debugfs_remove(attr->dentries.probability_file); | |
133 | attr->dentries.probability_file = NULL; | |
134 | ||
135 | debugfs_remove(attr->dentries.interval_file); | |
136 | attr->dentries.interval_file = NULL; | |
137 | ||
138 | debugfs_remove(attr->dentries.times_file); | |
139 | attr->dentries.times_file = NULL; | |
140 | ||
141 | debugfs_remove(attr->dentries.space_file); | |
142 | attr->dentries.space_file = NULL; | |
143 | ||
144 | debugfs_remove(attr->dentries.verbose_file); | |
145 | attr->dentries.verbose_file = NULL; | |
146 | ||
f4f154fd AM |
147 | debugfs_remove(attr->dentries.task_filter_file); |
148 | attr->dentries.task_filter_file = NULL; | |
149 | ||
6ff1cb35 AM |
150 | if (attr->dentries.dir) |
151 | WARN_ON(!simple_empty(attr->dentries.dir)); | |
152 | ||
153 | debugfs_remove(attr->dentries.dir); | |
154 | attr->dentries.dir = NULL; | |
155 | } | |
156 | ||
157 | int init_fault_attr_dentries(struct fault_attr *attr, const char *name) | |
158 | { | |
159 | mode_t mode = S_IFREG | S_IRUSR | S_IWUSR; | |
160 | struct dentry *dir; | |
161 | ||
162 | memset(&attr->dentries, 0, sizeof(attr->dentries)); | |
163 | ||
164 | dir = debugfs_create_dir(name, NULL); | |
165 | if (!dir) | |
166 | goto fail; | |
167 | attr->dentries.dir = dir; | |
168 | ||
169 | attr->dentries.probability_file = | |
170 | debugfs_create_ul("probability", mode, dir, &attr->probability); | |
171 | ||
172 | attr->dentries.interval_file = | |
173 | debugfs_create_ul("interval", mode, dir, &attr->interval); | |
174 | ||
175 | attr->dentries.times_file = | |
176 | debugfs_create_atomic_t("times", mode, dir, &attr->times); | |
177 | ||
178 | attr->dentries.space_file = | |
179 | debugfs_create_atomic_t("space", mode, dir, &attr->space); | |
180 | ||
181 | attr->dentries.verbose_file = | |
182 | debugfs_create_ul("verbose", mode, dir, &attr->verbose); | |
183 | ||
f4f154fd AM |
184 | attr->dentries.task_filter_file = debugfs_create_bool("task-filter", |
185 | mode, dir, &attr->task_filter); | |
186 | ||
6ff1cb35 AM |
187 | if (!attr->dentries.probability_file || !attr->dentries.interval_file |
188 | || !attr->dentries.times_file || !attr->dentries.space_file | |
f4f154fd | 189 | || !attr->dentries.verbose_file || !attr->dentries.task_filter_file) |
6ff1cb35 AM |
190 | goto fail; |
191 | ||
192 | return 0; | |
193 | fail: | |
194 | cleanup_fault_attr_dentries(attr); | |
195 | return -ENOMEM; | |
196 | } | |
197 | ||
198 | #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ |