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1// SPDX-License-Identifier: GPL-2.0-only2#include <linux/module.h>3 4#include "notifier-error-inject.h"5 6static int debugfs_errno_set(void *data, u64 val)7{8 *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);9 return 0;10}11 12static int debugfs_errno_get(void *data, u64 *val)13{14 *val = *(int *)data;15 return 0;16}17 18DEFINE_SIMPLE_ATTRIBUTE_SIGNED(fops_errno, debugfs_errno_get, debugfs_errno_set,19 "%lld\n");20 21static 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 27static 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 47struct dentry *notifier_err_inject_dir;48EXPORT_SYMBOL_GPL(notifier_err_inject_dir);49 50struct 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. If72 * notifier call chain is called with action->val, it will73 * fail with the error code74 */75 debugfs_create_errno("error", mode, action_dir, &action->error);76 }77 return dir;78}79EXPORT_SYMBOL_GPL(notifier_err_inject_init);80 81static 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 89static void __exit err_inject_exit(void)90{91 debugfs_remove_recursive(notifier_err_inject_dir);92}93 94module_init(err_inject_init);95module_exit(err_inject_exit);96 97MODULE_DESCRIPTION("Notifier error injection module");98MODULE_LICENSE("GPL");99MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");100