v4.19.13 snapshot.
diff --git a/drivers/base/module.c b/drivers/base/module.c
new file mode 100644
index 0000000..46ad4d6
--- /dev/null
+++ b/drivers/base/module.c
@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * module.c - module sysfs fun for drivers
+ */
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include "base.h"
+
+static char *make_driver_name(struct device_driver *drv)
+{
+ char *driver_name;
+
+ driver_name = kasprintf(GFP_KERNEL, "%s:%s", drv->bus->name, drv->name);
+ if (!driver_name)
+ return NULL;
+
+ return driver_name;
+}
+
+static void module_create_drivers_dir(struct module_kobject *mk)
+{
+ static DEFINE_MUTEX(drivers_dir_mutex);
+
+ mutex_lock(&drivers_dir_mutex);
+ if (mk && !mk->drivers_dir)
+ mk->drivers_dir = kobject_create_and_add("drivers", &mk->kobj);
+ mutex_unlock(&drivers_dir_mutex);
+}
+
+void module_add_driver(struct module *mod, struct device_driver *drv)
+{
+ char *driver_name;
+ int no_warn;
+ struct module_kobject *mk = NULL;
+
+ if (!drv)
+ return;
+
+ if (mod)
+ mk = &mod->mkobj;
+ else if (drv->mod_name) {
+ struct kobject *mkobj;
+
+ /* Lookup built-in module entry in /sys/modules */
+ mkobj = kset_find_obj(module_kset, drv->mod_name);
+ if (mkobj) {
+ mk = container_of(mkobj, struct module_kobject, kobj);
+ /* remember our module structure */
+ drv->p->mkobj = mk;
+ /* kset_find_obj took a reference */
+ kobject_put(mkobj);
+ }
+ }
+
+ if (!mk)
+ return;
+
+ /* Don't check return codes; these calls are idempotent */
+ no_warn = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module");
+ driver_name = make_driver_name(drv);
+ if (driver_name) {
+ module_create_drivers_dir(mk);
+ no_warn = sysfs_create_link(mk->drivers_dir, &drv->p->kobj,
+ driver_name);
+ kfree(driver_name);
+ }
+}
+
+void module_remove_driver(struct device_driver *drv)
+{
+ struct module_kobject *mk = NULL;
+ char *driver_name;
+
+ if (!drv)
+ return;
+
+ sysfs_remove_link(&drv->p->kobj, "module");
+
+ if (drv->owner)
+ mk = &drv->owner->mkobj;
+ else if (drv->p->mkobj)
+ mk = drv->p->mkobj;
+ if (mk && mk->drivers_dir) {
+ driver_name = make_driver_name(drv);
+ if (driver_name) {
+ sysfs_remove_link(mk->drivers_dir, driver_name);
+ kfree(driver_name);
+ }
+ }
+}