drivers/base/module.c

   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
  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
  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
  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
  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 }