1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/module.h>
3
4 #include "notifier-error-inject.h"
5
6 static int debugfs_errno_set(void *data, u64 val)
7 {
8 *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
9 return 0;
10 }
11
12 static int debugfs_errno_get(void *data, u64 *val)
13 {
14 *val = *(int *)data;
15 return 0;
16 }
17
18 DEFINE_SIMPLE_ATTRIBUTE_SIGNED(fops_errno, debugfs_errno_get, debugfs_errno_set,
19 "%lld\n");
20
21 static struct dentry *debugfs_create_errno(const char *name, umode_t mode,
22 struct dentry *parent, int *value)
23 {
24 return debugfs_create_file(name, mode, parent, value, &fops_errno);
25 }
26
27 static int notifier_err_inject_callback(struct notifier_block *nb,
28 unsigned long val, void *p)
29 {
30 int err = 0;
31 struct notifier_err_inject *err_inject =
32 container_of(nb, struct notifier_err_inject, nb);
33 struct notifier_err_inject_action *action;
34
35 for (action = err_inject->actions; action->name; action++) {
36 if (action->val == val) {
37 err = action->error;
38 break;
39 }
40 }
41 if (err)
42 pr_info("Injecting error (%d) to %s\n", err, action->name);
43
44 return notifier_from_errno(err);
45 }
46
47 struct dentry *notifier_err_inject_dir;
48 EXPORT_SYMBOL_GPL(notifier_err_inject_dir);
49
50 struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
51 struct notifier_err_inject *err_inject, int priority)
52 {
53 struct notifier_err_inject_action *action;
54 umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
55 struct dentry *dir;
56 struct dentry *actions_dir;
57
58 err_inject->nb.notifier_call = notifier_err_inject_callback;
59 err_inject->nb.priority = priority;
60
61 dir = debugfs_create_dir(name, parent);
62
63 actions_dir = debugfs_create_dir("actions", dir);
64
65 for (action = err_inject->actions; action->name; action++) {
66 struct dentry *action_dir;
67
68 action_dir = debugfs_create_dir(action->name, actions_dir);
69
70 /*
71 * Create debugfs r/w file containing action->error. If
72 * notifier call chain is called with action->val, it will
73 * fail with the error code
74 */
75 debugfs_create_errno("error", mode, action_dir, &action->error);
76 }
77 return dir;
78 }
79 EXPORT_SYMBOL_GPL(notifier_err_inject_init);
80
81 static int __init err_inject_init(void)
82 {
83 notifier_err_inject_dir =
84 debugfs_create_dir("notifier-error-inject", NULL);
85
86 return 0;
87 }
88
89 static void __exit err_inject_exit(void)
90 {
91 debugfs_remove_recursive(notifier_err_inject_dir);
92 }
93
94 module_init(err_inject_init);
95 module_exit(err_inject_exit);
96
97 MODULE_DESCRIPTION("Notifier error injection module");
98 MODULE_LICENSE("GPL");
99 MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
100
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