// SPDX-License-Identifier: GPL-2.0-only#include <linux/module.h> #include "notifier-error-inject.h" static int debugfs_errno_set(void *data, u64 val){	*(int *)data = clamp_t(int, val, -MAX_ERRNO, 0);	return 0;} static int debugfs_errno_get(void *data, u64 *val){	*val = *(int *)data;	return 0;} DEFINE_SIMPLE_ATTRIBUTE_SIGNED(fops_errno, debugfs_errno_get, debugfs_errno_set,			"%lld\n"); static struct dentry *debugfs_create_errno(const char *name, umode_t mode,				struct dentry *parent, int *value){	return debugfs_create_file(name, mode, parent, value, &fops_errno);} static int notifier_err_inject_callback(struct notifier_block *nb,				unsigned long val, void *p){	int err = 0;	struct notifier_err_inject *err_inject =		container_of(nb, struct notifier_err_inject, nb);	struct notifier_err_inject_action *action; 	for (action = err_inject->actions; action->name; action++) {		if (action->val == val) {			err = action->error;			break;		}	}	if (err)		pr_info("Injecting error (%d) to %s\n", err, action->name); 	return notifier_from_errno(err);} struct dentry *notifier_err_inject_dir;EXPORT_SYMBOL_GPL(notifier_err_inject_dir); struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent,			struct notifier_err_inject *err_inject, int priority){	struct notifier_err_inject_action *action;	umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;	struct dentry *dir;	struct dentry *actions_dir; 	err_inject->nb.notifier_call = notifier_err_inject_callback;	err_inject->nb.priority = priority; 	dir = debugfs_create_dir(name, parent); 	actions_dir = debugfs_create_dir("actions", dir); 	for (action = err_inject->actions; action->name; action++) {		struct dentry *action_dir; 		action_dir = debugfs_create_dir(action->name, actions_dir); 		/*		 * Create debugfs r/w file containing action->error. If		 * notifier call chain is called with action->val, it will		 * fail with the error code		 */		debugfs_create_errno("error", mode, action_dir, &action->error);	}	return dir;}EXPORT_SYMBOL_GPL(notifier_err_inject_init); static int __init err_inject_init(void){	notifier_err_inject_dir =		debugfs_create_dir("notifier-error-inject", NULL); 	return 0;} static void __exit err_inject_exit(void){	debugfs_remove_recursive(notifier_err_inject_dir);} module_init(err_inject_init);module_exit(err_inject_exit); MODULE_DESCRIPTION("Notifier error injection module");MODULE_LICENSE("GPL");MODULE_AUTHOR("Akinobu Mita <akinobu.mita@gmail.com>");