1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun #include <linux/module.h>
3*4882a593Smuzhiyun
4*4882a593Smuzhiyun #include "notifier-error-inject.h"
5*4882a593Smuzhiyun
debugfs_errno_set(void * data,u64 val)6*4882a593Smuzhiyun static int debugfs_errno_set(void *data, u64 val)
7*4882a593Smuzhiyun {
8*4882a593Smuzhiyun *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);
9*4882a593Smuzhiyun return 0;
10*4882a593Smuzhiyun }
11*4882a593Smuzhiyun
debugfs_errno_get(void * data,u64 * val)12*4882a593Smuzhiyun static int debugfs_errno_get(void *data, u64 *val)
13*4882a593Smuzhiyun {
14*4882a593Smuzhiyun *val = *(int *)data;
15*4882a593Smuzhiyun return 0;
16*4882a593Smuzhiyun }
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set,
19*4882a593Smuzhiyun "%lld\n");
20*4882a593Smuzhiyun
debugfs_create_errno(const char * name,umode_t mode,struct dentry * parent,int * value)21*4882a593Smuzhiyun static struct dentry *debugfs_create_errno(const char *name, umode_t mode,
22*4882a593Smuzhiyun struct dentry *parent, int *value)
23*4882a593Smuzhiyun {
24*4882a593Smuzhiyun return debugfs_create_file(name, mode, parent, value, &fops_errno);
25*4882a593Smuzhiyun }
26*4882a593Smuzhiyun
notifier_err_inject_callback(struct notifier_block * nb,unsigned long val,void * p)27*4882a593Smuzhiyun static int notifier_err_inject_callback(struct notifier_block *nb,
28*4882a593Smuzhiyun unsigned long val, void *p)
29*4882a593Smuzhiyun {
30*4882a593Smuzhiyun int err = 0;
31*4882a593Smuzhiyun struct notifier_err_inject *err_inject =
32*4882a593Smuzhiyun container_of(nb, struct notifier_err_inject, nb);
33*4882a593Smuzhiyun struct notifier_err_inject_action *action;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun for (action = err_inject->actions; action->name; action++) {
36*4882a593Smuzhiyun if (action->val == val) {
37*4882a593Smuzhiyun err = action->error;
38*4882a593Smuzhiyun break;
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun }
41*4882a593Smuzhiyun if (err)
42*4882a593Smuzhiyun pr_info("Injecting error (%d) to %s\n", err, action->name);
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun return notifier_from_errno(err);
45*4882a593Smuzhiyun }
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun struct dentry *notifier_err_inject_dir;
48*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(notifier_err_inject_dir);
49*4882a593Smuzhiyun
notifier_err_inject_init(const char * name,struct dentry * parent,struct notifier_err_inject * err_inject,int priority)50*4882a593Smuzhiyun struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,
51*4882a593Smuzhiyun struct notifier_err_inject *err_inject, int priority)
52*4882a593Smuzhiyun {
53*4882a593Smuzhiyun struct notifier_err_inject_action *action;
54*4882a593Smuzhiyun umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
55*4882a593Smuzhiyun struct dentry *dir;
56*4882a593Smuzhiyun struct dentry *actions_dir;
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun err_inject->nb.notifier_call = notifier_err_inject_callback;
59*4882a593Smuzhiyun err_inject->nb.priority = priority;
60*4882a593Smuzhiyun
61*4882a593Smuzhiyun dir = debugfs_create_dir(name, parent);
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun actions_dir = debugfs_create_dir("actions", dir);
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun for (action = err_inject->actions; action->name; action++) {
66*4882a593Smuzhiyun struct dentry *action_dir;
67*4882a593Smuzhiyun
68*4882a593Smuzhiyun action_dir = debugfs_create_dir(action->name, actions_dir);
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun /*
71*4882a593Smuzhiyun * Create debugfs r/w file containing action->error. If
72*4882a593Smuzhiyun * notifier call chain is called with action->val, it will
73*4882a593Smuzhiyun * fail with the error code
74*4882a593Smuzhiyun */
75*4882a593Smuzhiyun debugfs_create_errno("error", mode, action_dir, &action->error);
76*4882a593Smuzhiyun }
77*4882a593Smuzhiyun return dir;
78*4882a593Smuzhiyun }
79*4882a593Smuzhiyun EXPORT_SYMBOL_GPL(notifier_err_inject_init);
80*4882a593Smuzhiyun
err_inject_init(void)81*4882a593Smuzhiyun static int __init err_inject_init(void)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun notifier_err_inject_dir =
84*4882a593Smuzhiyun debugfs_create_dir("notifier-error-inject", NULL);
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun if (!notifier_err_inject_dir)
87*4882a593Smuzhiyun return -ENOMEM;
88*4882a593Smuzhiyun
89*4882a593Smuzhiyun return 0;
90*4882a593Smuzhiyun }
91*4882a593Smuzhiyun
err_inject_exit(void)92*4882a593Smuzhiyun static void __exit err_inject_exit(void)
93*4882a593Smuzhiyun {
94*4882a593Smuzhiyun debugfs_remove_recursive(notifier_err_inject_dir);
95*4882a593Smuzhiyun }
96*4882a593Smuzhiyun
97*4882a593Smuzhiyun module_init(err_inject_init);
98*4882a593Smuzhiyun module_exit(err_inject_exit);
99*4882a593Smuzhiyun
100*4882a593Smuzhiyun MODULE_DESCRIPTION("Notifier error injection module");
101*4882a593Smuzhiyun MODULE_LICENSE("GPL");
102*4882a593Smuzhiyun MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");
103