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 
make_driver_name(struct device_driver * drv)12 static 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 
module_create_drivers_dir(struct module_kobject * mk)23 static 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 
module_add_driver(struct module * mod,struct device_driver * drv)33 void 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 
module_remove_driver(struct device_driver * drv)72 void 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