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   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/slab.h>
  11 #include <linux/string.h>
  12 #include "base.h"
  13
  14 static char *make_driver_name(struct device_driver *drv)
  15 {
  16         char *driver_name;
  17
  18         driver_name = kmalloc(strlen(drv->name) + strlen(drv->bus->name) + 2,
  19                               GFP_KERNEL);
  20         if (!driver_name)
  21                 return NULL;
  22
  23         sprintf(driver_name, "%s:%s", drv->bus->name, drv->name);
  24         return driver_name;
  25 }
  26
  27 static void module_create_drivers_dir(struct module_kobject *mk)
  28 {
  29         if (!mk || mk->drivers_dir)
  30                 return;
  31
  32         mk->drivers_dir = kobject_create_and_add("drivers", &mk->kobj);
  33 }
  34
  35 void module_add_driver(struct module *mod, struct device_driver *drv)
  36 {
  37         char *driver_name;
  38         int no_warn;
  39         struct module_kobject *mk = NULL;
  40
  41         if (!drv)
  42                 return;
  43
  44         if (mod)
  45                 mk = &mod->mkobj;
  46         else if (drv->mod_name) {
  47                 struct kobject *mkobj;
  48
  49                 /* Lookup built-in module entry in /sys/modules */
  50                 mkobj = kset_find_obj(module_kset, drv->mod_name);
  51                 if (mkobj) {
  52                         mk = container_of(mkobj, struct module_kobject, kobj);
  53                         /* remember our module structure */
  54                         drv->p->mkobj = mk;
  55                         /* kset_find_obj took a reference */
  56                         kobject_put(mkobj);
  57                 }
  58         }
  59
  60         if (!mk)
  61                 return;
  62
  63         /* Don't check return codes; these calls are idempotent */
  64         no_warn = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module");
  65         driver_name = make_driver_name(drv);
  66         if (driver_name) {
  67                 module_create_drivers_dir(mk);
  68                 no_warn = sysfs_create_link(mk->drivers_dir, &drv->p->kobj,
  69                                             driver_name);
  70                 kfree(driver_name);
  71         }
  72 }
  73
  74 void module_remove_driver(struct device_driver *drv)
  75 {
  76         struct module_kobject *mk = NULL;
  77         char *driver_name;
  78
  79         if (!drv)
  80                 return;
  81
  82         sysfs_remove_link(&drv->p->kobj, "module");
  83
  84         if (drv->owner)
  85                 mk = &drv->owner->mkobj;
  86         else if (drv->p->mkobj)
  87                 mk = drv->p->mkobj;
  88         if (mk && mk->drivers_dir) {
  89                 driver_name = make_driver_name(drv);
  90                 if (driver_name) {
  91                         sysfs_remove_link(mk->drivers_dir, driver_name);
  92                         kfree(driver_name);
  93                 }
  94         }
  95 }