1// SPDX-License-Identifier: GPL-2.0
2/*
3 * module.c - module sysfs fun for drivers
4 */
5#include <linux/device.h>
6#include <linux/module.h>
7#include <linux/errno.h>
8#include <linux/slab.h>
9#include <linux/string.h>
10#include "base.h"
11
12static char *make_driver_name(struct device_driver *drv)
13{
14	char *driver_name;
15
16	driver_name = kasprintf(GFP_KERNEL, "%s:%s", drv->bus->name, drv->name);
17	if (!driver_name)
18		return NULL;
19
20	return driver_name;
21}
22
23static void module_create_drivers_dir(struct module_kobject *mk)
24{
25	static DEFINE_MUTEX(drivers_dir_mutex);
26
27	mutex_lock(&drivers_dir_mutex);
28	if (mk && !mk->drivers_dir)
29		mk->drivers_dir = kobject_create_and_add("drivers", &mk->kobj);
30	mutex_unlock(&drivers_dir_mutex);
31}
32
33void module_add_driver(struct module *mod, struct device_driver *drv)
34{
35	char *driver_name;
36	int no_warn;
37	struct module_kobject *mk = NULL;
38
39	if (!drv)
40		return;
41
42	if (mod)
43		mk = &mod->mkobj;
44	else if (drv->mod_name) {
45		struct kobject *mkobj;
46
47		/* Lookup built-in module entry in /sys/modules */
48		mkobj = kset_find_obj(module_kset, drv->mod_name);
49		if (mkobj) {
50			mk = container_of(mkobj, struct module_kobject, kobj);
51			/* remember our module structure */
52			drv->p->mkobj = mk;
53			/* kset_find_obj took a reference */
54			kobject_put(mkobj);
55		}
56	}
57
58	if (!mk)
59		return;
60
61	/* Don't check return codes; these calls are idempotent */
62	no_warn = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module");
63	driver_name = make_driver_name(drv);
64	if (driver_name) {
65		module_create_drivers_dir(mk);
66		no_warn = sysfs_create_link(mk->drivers_dir, &drv->p->kobj,
67					    driver_name);
68		kfree(driver_name);
69	}
70}
71
72void module_remove_driver(struct device_driver *drv)
73{
74	struct module_kobject *mk = NULL;
75	char *driver_name;
76
77	if (!drv)
78		return;
79
80	sysfs_remove_link(&drv->p->kobj, "module");
81
82	if (drv->owner)
83		mk = &drv->owner->mkobj;
84	else if (drv->p->mkobj)
85		mk = drv->p->mkobj;
86	if (mk && mk->drivers_dir) {
87		driver_name = make_driver_name(drv);
88		if (driver_name) {
89			sysfs_remove_link(mk->drivers_dir, driver_name);
90			kfree(driver_name);
91		}
92	}
93}
94