drivers/base/module.c

   1 /*
   2  * module.c - module sysfs fun for drivers
   3  *
   4  * This file is released under the GPLv2
   5  *
   6  */
   7 #include <linux/device.h>
   8 #include <linux/module.h>
   9 #include <linux/errno.h>
  10 #include <linux/string.h>
  11 #include "base.h"
  12
  13 static char *make_driver_name(struct device_driver *drv)
  14 {
  15         char *driver_name;
  16
  17         driver_name = kmalloc(strlen(drv->name) + strlen(drv->bus->name) + 2,
  18                               GFP_KERNEL);
  19         if (!driver_name)
  20                 return NULL;
  21
  22         sprintf(driver_name, "%s:%s", drv->bus->name, drv->name);
  23         return driver_name;
  24 }
  25
  26 static void module_create_drivers_dir(struct module_kobject *mk)
  27 {
  28         if (!mk || mk->drivers_dir)
  29                 return;
  30
  31         mk->drivers_dir = kobject_create_and_add("drivers", &mk->kobj);
  32 }
  33
  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
  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         sysfs_remove_link(&drv->p->kobj, "module");
  82
  83         if (drv->owner)
  84                 mk = &drv->owner->mkobj;
  85         else if (drv->p->mkobj)
  86                 mk = drv->p->mkobj;
  87         if (mk && mk->drivers_dir) {
  88                 driver_name = make_driver_name(drv);
  89                 if (driver_name) {
  90                         sysfs_remove_link(mk->drivers_dir, driver_name);
  91                         kfree(driver_name);
  92                 }
  93         }
  94 }