[PATCH] driver core: fix built-in drivers sysfs links

built-in drivers had broken sysfs links that caused bootup hangs for
certain driver unregistry sequences.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 15 insertions, 4 deletions

diff --git a/include/linux/device.h b/include/linux/device.h
index caad9bba9652..5cf30e95c8b6 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -128,6 +128,7 @@ struct device_driver {
 
         struct module           * owner;
         const char              * mod_name;     /* used for built-in modules */
+        struct module_kobject   * mkobj;
 
         int     (*probe)        (struct device * dev);
         int     (*remove)       (struct device * dev);
diff --git a/kernel/module.c b/kernel/module.c
index fbc51de6444e..dcdb32b8b13c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2384,8 +2384,13 @@ void module_add_driver(struct module *mod, struct device_driver *drv)
 
                 /* Lookup built-in module entry in /sys/modules */
                 mkobj = kset_find_obj(&module_subsys.kset, drv->mod_name);
-                if (mkobj)
+                if (mkobj) {
                         mk = container_of(mkobj, struct module_kobject, kobj);
+                        /* remember our module structure */
+                        drv->mkobj = mk;
+                        /* kset_find_obj took a reference */
+                        kobject_put(mkobj);
+                }
         }
 
         if (!mk)
@@ -2405,17 +2410,22 @@ EXPORT_SYMBOL(module_add_driver);
 
 void module_remove_driver(struct device_driver *drv)
 {
+        struct module_kobject *mk = NULL;
         char *driver_name;
 
         if (!drv)
                 return;
 
         sysfs_remove_link(&drv->kobj, "module");
-        if (drv->owner && drv->owner->mkobj.drivers_dir) {
+
+        if (drv->owner)
+                mk = &drv->owner->mkobj;
+        else if (drv->mkobj)
+                mk = drv->mkobj;
+        if (mk && mk->drivers_dir) {
                 driver_name = make_driver_name(drv);
                 if (driver_name) {
-                        sysfs_remove_link(drv->owner->mkobj.drivers_dir,
-                                          driver_name);
+                        sysfs_remove_link(mk->drivers_dir, driver_name);
                         kfree(driver_name);
                 }
         }