[PATCH] Driver Core: remove driver model detach_state

The driver model has a "detach_state" mechanism that:

 - Has never been used by any in-kernel drive;
 - Is superfluous, since driver remove() methods can do the same thing;
 - Became buggy when the suspend() parameter changed semantics and type;
 - Could self-deadlock when called from certain suspend contexts;
 - Is effectively wasted documentation, object code, and headspace.

This removes that "detach_state" mechanism; net code shrink, as well
as a per-device saving in the driver model and sysfs.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

6 files changed, 1 insertions, 83 deletions

diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index 6662b54..a47928a2 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -1,6 +1,6 @@
 # Makefile for the Linux device tree
 
-obj-y			:= core.o sys.o interface.o bus.o \
+obj-y			:= core.o sys.o bus.o \
 			   driver.o class.o class_simple.o platform.o \
 			   cpu.o firmware.o init.o map.o dmapool.o \
 			   attribute_container.o transport_class.o
diff --git a/drivers/base/bus.c b/drivers/base/bus.c
index 2b3902c..3cb04bb 100644
--- a/drivers/base/bus.c
+++ b/drivers/base/bus.c
@@ -390,7 +390,6 @@ void device_release_driver(struct device * dev)
 		sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
 		sysfs_remove_link(&dev->kobj, "driver");
 		list_del_init(&dev->driver_list);
-		device_detach_shutdown(dev);
 		if (drv->remove)
 			drv->remove(dev);
 		dev->driver = NULL;
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 268a9c8..d21eb77 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -31,8 +31,6 @@ int (*platform_notify_remove)(struct device * dev) = NULL;
 #define to_dev(obj) container_of(obj, struct device, kobj)
 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
 
-extern struct attribute * dev_default_attrs[];
-
 static ssize_t
 dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
 {
@@ -89,7 +87,6 @@ static void device_release(struct kobject * kobj)
 static struct kobj_type ktype_device = {
 	.release	= device_release,
 	.sysfs_ops	= &dev_sysfs_ops,
-	.default_attrs	= dev_default_attrs,
 };
 
 
diff --git a/drivers/base/interface.c b/drivers/base/interface.c
deleted file mode 100644
index bd51584..0000000
--- a/drivers/base/interface.c
+++ /dev/null
@@ -1,51 +0,0 @@
-/*
- * drivers/base/interface.c - common driverfs interface that's exported to
- * 	the world for all devices.
- *
- * Copyright (c) 2002-3 Patrick Mochel
- * Copyright (c) 2002-3 Open Source Development Labs
- *
- * This file is released under the GPLv2
- *
- */
-
-#include <linux/device.h>
-#include <linux/err.h>
-#include <linux/stat.h>
-#include <linux/string.h>
-
-/**
- *	detach_state - control the default power state for the device.
- *
- *	This is the state the device enters when it's driver module is
- *	unloaded. The value is an unsigned integer, in the range of 0-4.
- *	'0' indicates 'On', so no action will be taken when the driver is
- *	unloaded. This is the default behavior.
- *	'4' indicates 'Off', meaning the driver core will call the driver's
- *	shutdown method to quiesce the device.
- *	1-3 indicate a low-power state for the device to enter via the
- *	driver's suspend method.
- */
-
-static ssize_t detach_show(struct device * dev, char * buf)
-{
-	return sprintf(buf, "%u\n", dev->detach_state);
-}
-
-static ssize_t detach_store(struct device * dev, const char * buf, size_t n)
-{
-	u32 state;
-	state = simple_strtoul(buf, NULL, 10);
-	if (state > 4)
-		return -EINVAL;
-	dev->detach_state = state;
-	return n;
-}
-
-static DEVICE_ATTR(detach_state, 0644, detach_show, detach_store);
-
-
-struct attribute * dev_default_attrs[] = {
-	&dev_attr_detach_state.attr,
-	NULL,
-};
diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
index e5eda74..2e700d7 100644
--- a/drivers/base/power/power.h
+++ b/drivers/base/power/power.h
@@ -1,18 +1,7 @@
-
-
-enum {
-	DEVICE_PM_ON,
-	DEVICE_PM1,
-	DEVICE_PM2,
-	DEVICE_PM3,
-	DEVICE_PM_OFF,
-};
-
 /*
  * shutdown.c
  */
 
-extern int device_detach_shutdown(struct device *);
 extern void device_shutdown(void);
 
 
diff --git a/drivers/base/power/shutdown.c b/drivers/base/power/shutdown.c
index 9797990..f50a08b 100644
--- a/drivers/base/power/shutdown.c
+++ b/drivers/base/power/shutdown.c
@@ -19,22 +19,6 @@
 extern struct subsystem devices_subsys;
 
 
-int device_detach_shutdown(struct device * dev)
-{
-	if (!dev->detach_state)
-		return 0;
-
-	if (dev->detach_state == DEVICE_PM_OFF) {
-		if (dev->driver && dev->driver->shutdown) {
-			dev_dbg(dev, "shutdown\n");
-			dev->driver->shutdown(dev);
-		}
-		return 0;
-	}
-	return dpm_runtime_suspend(dev, dev->detach_state);
-}
-
-
 /**
  * We handle system devices differently - we suspend and shut them
  * down last and resume them first. That way, we don't do anything stupid like