EDAC: Rip out the edac_subsys reference counting

This was really dumb - reference counting for the main EDAC sysfs
object. While we could've simply registered it as the first thing in the
module init path and then hand it around to what needs it.

Do that and rip out all the code around it, thus simplifying the whole
handling significantly.

Move the edac_subsys node back to edac_module.c.

Signed-off-by: Borislav Petkov <[e-mail]>

drivers/edac/edac_device_sysfs.c

···
 
 	if (!try_module_get(edac_dev->owner)) {
 		err = -ENODEV;
-		goto err_mod_get;
+		goto err_out;
 	}
 
 	/* register */
···
 err_kobj_reg:
 	module_put(edac_dev->owner);
 
-err_mod_get:
-	edac_put_sysfs_subsys();
-
 err_out:
 	return err;
 }
···
 	 *   b) 'kfree' the memory
 	 */
 	kobject_put(&dev->kobj);
-	edac_put_sysfs_subsys();
 }
 
 /* edac_dev -> instance information */

drivers/edac/edac_mc_sysfs.c

···
 	mci_pdev = kzalloc(sizeof(*mci_pdev), GFP_KERNEL);
 	if (!mci_pdev) {
 		err = -ENOMEM;
-		goto out_put_sysfs;
+		goto out;
 	}
 
 	mci_pdev->bus = edac_subsys;
···
 
  out_dev_free:
 	kfree(mci_pdev);
- out_put_sysfs:
-	edac_put_sysfs_subsys();
  out:
 	return err;
 }
···
 void edac_mc_sysfs_exit(void)
 {
 	device_unregister(mci_pdev);
-	edac_put_sysfs_subsys();
 }

drivers/edac/edac_module.c

···
 }
 
 /*
+ * sysfs object: /sys/devices/system/edac
+ *	need to export to other files
+ */
+struct bus_type edac_subsys = {
+	.name = "edac",
+	.dev_name = "edac",
+};
+EXPORT_SYMBOL_GPL(edac_subsys);
+
+static int edac_subsys_init(void)
+{
+	int err;
+
+	/* create the /sys/devices/system/edac directory */
+	err = subsys_system_register(&edac_subsys, NULL);
+	if (err)
+		printk(KERN_ERR "Error registering toplevel EDAC sysfs dir\n");
+
+	return err;
+}
+
+static void edac_subsys_exit(void)
+{
+	bus_unregister(&edac_subsys);
+}
+
+/* return pointer to the 'edac' node in sysfs */
+struct bus_type *edac_get_sysfs_subsys(void)
+{
+	return &edac_subsys;
+}
+EXPORT_SYMBOL_GPL(edac_get_sysfs_subsys);
+/*
  * edac_init
  *      module initialization entry point
  */
···
 	int err = 0;
 
 	edac_printk(KERN_INFO, EDAC_MC, EDAC_VERSION "\n");
+
+	err = edac_subsys_init();
+	if (err)
+		return err;
 
 	/*
 	 * Harvest and clear any boot/initialization PCI parity errors
···
 	edac_mc_sysfs_exit();
 
 err_sysfs:
+	edac_subsys_exit();
+
 	return err;
 }
 
···
 	edac_workqueue_teardown();
 	edac_mc_sysfs_exit();
 	edac_debugfs_exit();
+	edac_subsys_exit();
 }
 
 /*

drivers/edac/edac_pci_sysfs.c

···
 	if (!try_module_get(THIS_MODULE)) {
 		edac_dbg(1, "try_module_get() failed\n");
 		err = -ENODEV;
-		goto mod_get_fail;
+		goto decrement_count_fail;
 	}
 
 	edac_pci_top_main_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
···
 kzalloc_fail:
 	module_put(THIS_MODULE);
 
-mod_get_fail:
-	edac_put_sysfs_subsys();
-
 decrement_count_fail:
 	/* if are on this error exit, nothing to tear down */
 	atomic_dec(&edac_pci_sysfs_refcount);
···
 	if (atomic_dec_return(&edac_pci_sysfs_refcount) == 0) {
 		edac_dbg(0, "called kobject_put on main kobj\n");
 		kobject_put(edac_pci_top_main_kobj);
-		edac_put_sysfs_subsys();
 	}
 }
 

drivers/edac/edac_stub.c

···
 int edac_err_assert = 0;
 EXPORT_SYMBOL_GPL(edac_err_assert);
 
-static atomic_t edac_subsys_valid = ATOMIC_INIT(0);
-
 int edac_report_status = EDAC_REPORTING_ENABLED;
 EXPORT_SYMBOL_GPL(edac_report_status);
 
···
 	edac_err_assert++;
 }
 EXPORT_SYMBOL_GPL(edac_atomic_assert_error);
-
-/*
- * sysfs object: /sys/devices/system/edac
- *	need to export to other files
- */
-struct bus_type edac_subsys = {
-	.name = "edac",
-	.dev_name = "edac",
-};
-EXPORT_SYMBOL_GPL(edac_subsys);
-
-/* return pointer to the 'edac' node in sysfs */
-struct bus_type *edac_get_sysfs_subsys(void)
-{
-	int err = 0;
-
-	if (atomic_read(&edac_subsys_valid))
-		goto out;
-
-	/* create the /sys/devices/system/edac directory */
-	err = subsys_system_register(&edac_subsys, NULL);
-	if (err) {
-		printk(KERN_ERR "Error registering toplevel EDAC sysfs dir\n");
-		return NULL;
-	}
-
-out:
-	atomic_inc(&edac_subsys_valid);
-	return &edac_subsys;
-}
-EXPORT_SYMBOL_GPL(edac_get_sysfs_subsys);
-
-void edac_put_sysfs_subsys(void)
-{
-	/* last user unregisters it */
-	if (atomic_dec_and_test(&edac_subsys_valid))
-		bus_unregister(&edac_subsys);
-}
-EXPORT_SYMBOL_GPL(edac_put_sysfs_subsys);

include/linux/edac.h

···
 extern int edac_handler_set(void);
 extern void edac_atomic_assert_error(void);
 extern struct bus_type *edac_get_sysfs_subsys(void);
-extern void edac_put_sysfs_subsys(void);
 
 enum {
 	EDAC_REPORTING_ENABLED,