Driver core: move the driver specific module code into the driver core

The module driver specific code should belong in the driver core, not in
the kernel/ directory.  So move this code.  This is done in preparation
for some struct device_driver rework that should be confined to the
driver core code only.

This also lets us keep from exporting these functions, as no external
code should ever be calling it.

Thanks to Andrew Morton for the !CONFIG_MODULES fix.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 104 insertions, 0 deletions

diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index b39ea3f59c9b..ff2696823f8d 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_FW_LOADER)	+= firmware_class.o
 obj-$(CONFIG_NUMA)	+= node.o
 obj-$(CONFIG_MEMORY_HOTPLUG_SPARSE) += memory.o
 obj-$(CONFIG_SMP)	+= topology.o
+obj-$(CONFIG_MODULES)	+= module.o
 obj-$(CONFIG_SYS_HYPERVISOR) += hypervisor.o
 
 ifeq ($(CONFIG_DEBUG_DRIVER),y)
diff --git a/drivers/base/base.h b/drivers/base/base.h
index ca6d273064f8..05472360f6a2 100644
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -73,3 +73,12 @@ extern char *make_class_name(const char *name, struct kobject *kobj);
 extern int devres_release_all(struct device *dev);
 
 extern struct kset *devices_kset;
+
+#ifdef CONFIG_MODULES
+extern void module_add_driver(struct module *mod, struct device_driver *drv);
+extern void module_remove_driver(struct device_driver *drv);
+#else
+static inline void module_add_driver(struct module *mod,
+				     struct device_driver *drv) { }
+static inline void module_remove_driver(struct device_driver *drv) { }
+#endif
diff --git a/drivers/base/module.c b/drivers/base/module.c
new file mode 100644
index 000000000000..cad07be5de1a
--- /dev/null
+++ b/drivers/base/module.c
@@ -0,0 +1,94 @@
+/*
+ * module.c - module sysfs fun for drivers
+ *
+ * This file is released under the GPLv2
+ *
+ */
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include "base.h"
+
+static char *make_driver_name(struct device_driver *drv)
+{
+	char *driver_name;
+
+	driver_name = kmalloc(strlen(drv->name) + strlen(drv->bus->name) + 2,
+			      GFP_KERNEL);
+	if (!driver_name)
+		return NULL;
+
+	sprintf(driver_name, "%s:%s", drv->bus->name, drv->name);
+	return driver_name;
+}
+
+static void module_create_drivers_dir(struct module_kobject *mk)
+{
+	if (!mk || mk->drivers_dir)
+		return;
+
+	mk->drivers_dir = kobject_create_and_add("drivers", &mk->kobj);
+}
+
+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->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->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->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->kobj, "module");
+
+	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(mk->drivers_dir, driver_name);
+			kfree(driver_name);
+		}
+	}
+}