// SPDX-License-Identifier: GPL-2.0/* * module.c - module sysfs fun for drivers */#include <linux/device.h>#include <linux/module.h>#include <linux/errno.h>#include <linux/slab.h>#include <linux/string.h>#include <linux/rcupdate.h>#include "base.h" static char *make_driver_name(const struct device_driver *drv){	char *driver_name; 	driver_name = kasprintf(GFP_KERNEL, "%s:%s", drv->bus->name, drv->name);	if (!driver_name)		return NULL; 	return driver_name;} static void module_create_drivers_dir(struct module_kobject *mk){	static DEFINE_MUTEX(drivers_dir_mutex); 	mutex_lock(&drivers_dir_mutex);	if (mk && !mk->drivers_dir)		mk->drivers_dir = kobject_create_and_add("drivers", &mk->kobj);	mutex_unlock(&drivers_dir_mutex);} int module_add_driver(struct module *mod, const struct device_driver *drv){	char *driver_name;	struct module_kobject *mk = NULL;	int ret; 	if (!drv)		return 0; 	if (mod)		mk = &mod->mkobj;	else if (drv->mod_name) {		struct kobject *mkobj; 		/* Lookup built-in module entry in /sys/modules */		mkobj = kset_find_obj(module_kset, drv->mod_name);		if (mkobj) {			mk = container_of(mkobj, struct module_kobject, kobj);			/* remember our module structure */			drv->p->mkobj = mk;			/* kset_find_obj took a reference */			kobject_put(mkobj);		}	} 	if (!mk)		return 0; 	ret = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module");	if (ret)		return ret; 	driver_name = make_driver_name(drv);	if (!driver_name) {		ret = -ENOMEM;		goto out;	} 	module_create_drivers_dir(mk);	if (!mk->drivers_dir) {		ret = -EINVAL;		goto out;	} 	ret = sysfs_create_link(mk->drivers_dir, &drv->p->kobj, driver_name);	if (ret)		goto out; 	kfree(driver_name); 	return 0;out:	sysfs_remove_link(&drv->p->kobj, "module");	sysfs_remove_link(mk->drivers_dir, driver_name);	kfree(driver_name); 	return ret;} void module_remove_driver(const struct device_driver *drv){	struct module_kobject *mk = NULL;	char *driver_name; 	if (!drv)		return; 	/* Synchronize with dev_uevent() */	synchronize_rcu(); 	sysfs_remove_link(&drv->p->kobj, "module"); 	if (drv->owner)		mk = &drv->owner->mkobj;	else if (drv->p->mkobj)		mk = drv->p->mkobj;	if (mk && mk->drivers_dir) {		driver_name = make_driver_name(drv);		if (driver_name) {			sysfs_remove_link(mk->drivers_dir, driver_name);			kfree(driver_name);		}	}}