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
make_driver_name(struct device_driver *drv)13 static 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
module_create_drivers_dir(struct module_kobject *mk)24 static 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
module_add_driver(struct module *mod, struct device_driver *drv)34 void 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
module_remove_driver(struct device_driver *drv)73 void 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