xref: /kernel/linux/linux-5.10/drivers/base/module.c (revision 8c2ecf20) 
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 <linux/rcupdate.h>
11#include "base.h"
12
13static char *make_driver_name(struct device_driver *drv)
14{
15	char *driver_name;
16
17	driver_name = kasprintf(GFP_KERNEL, "%s:%s", drv->bus->name, drv->name);
18	if (!driver_name)
19		return NULL;
20
21	return driver_name;
22}
23
24static void module_create_drivers_dir(struct module_kobject *mk)
25{
26	static DEFINE_MUTEX(drivers_dir_mutex);
27
28	mutex_lock(&drivers_dir_mutex);
29	if (mk && !mk->drivers_dir)
30		mk->drivers_dir = kobject_create_and_add("drivers", &mk->kobj);
31	mutex_unlock(&drivers_dir_mutex);
32}
33
34void module_add_driver(struct module *mod, struct device_driver *drv)
35{
36	char *driver_name;
37	int no_warn;
38	struct module_kobject *mk = NULL;
39
40	if (!drv)
41		return;
42
43	if (mod)
44		mk = &mod->mkobj;
45	else if (drv->mod_name) {
46		struct kobject *mkobj;
47
48		/* Lookup built-in module entry in /sys/modules */
49		mkobj = kset_find_obj(module_kset, drv->mod_name);
50		if (mkobj) {
51			mk = container_of(mkobj, struct module_kobject, kobj);
52			/* remember our module structure */
53			drv->p->mkobj = mk;
54			/* kset_find_obj took a reference */
55			kobject_put(mkobj);
56		}
57	}
58
59	if (!mk)
60		return;
61
62	/* Don't check return codes; these calls are idempotent */
63	no_warn = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module");
64	driver_name = make_driver_name(drv);
65	if (driver_name) {
66		module_create_drivers_dir(mk);
67		no_warn = sysfs_create_link(mk->drivers_dir, &drv->p->kobj,
68					    driver_name);
69		kfree(driver_name);
70	}
71}
72
73void module_remove_driver(struct device_driver *drv)
74{
75	struct module_kobject *mk = NULL;
76	char *driver_name;
77
78	if (!drv)
79		return;
80
81	/* Synchronize with dev_uevent() */
82	synchronize_rcu();
83
84	sysfs_remove_link(&drv->p->kobj, "module");
85
86	if (drv->owner)
87		mk = &drv->owner->mkobj;
88	else if (drv->p->mkobj)
89		mk = drv->p->mkobj;
90	if (mk && mk->drivers_dir) {
91		driver_name = make_driver_name(drv);
92		if (driver_name) {
93			sysfs_remove_link(mk->drivers_dir, driver_name);
94			kfree(driver_name);
95		}
96	}
97}
98