driver-core: implement 'sysdev' functionality for regular devices and buses

All sysdev classes and sysdev devices will converted to regular devices
and buses to properly hook userspace into the event processing.

There is no interesting difference between a 'sysdev' and 'device' which
would justify to roll an entire own subsystem with different userspace
export semantics. Userspace relies on events and generic sysfs subsystem
infrastructure from sysdev devices, which are currently not properly
available.

Every converted sysdev class will create a regular device with the class
name in /sys/devices/system and all registered devices will becom a children
of theses devices.

For compatibility reasons, the sysdev class-wide attributes are created
at this parent device. (Do not copy that logic for anything new, subsystem-
wide properties belong to the subsystem, not to some fake parent device
created in /sys/devices.)

Every sysdev driver is implemented as a simple subsystem interface now,
and no longer called a driver.

After all sysdev classes are ported to regular driver core entities, the
sysdev implementation will be entirely removed from the kernel.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 69 insertions, 16 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 82c86545..a31ea19 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -117,6 +117,56 @@ static const struct sysfs_ops dev_sysfs_ops = {
 	.store	= dev_attr_store,
 };
 
+#define to_ext_attr(x) container_of(x, struct dev_ext_attribute, attr)
+
+ssize_t device_store_ulong(struct device *dev,
+			   struct device_attribute *attr,
+			   const char *buf, size_t size)
+{
+	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	char *end;
+	unsigned long new = simple_strtoul(buf, &end, 0);
+	if (end == buf)
+		return -EINVAL;
+	*(unsigned long *)(ea->var) = new;
+	/* Always return full write size even if we didn't consume all */
+	return size;
+}
+EXPORT_SYMBOL_GPL(device_store_ulong);
+
+ssize_t device_show_ulong(struct device *dev,
+			  struct device_attribute *attr,
+			  char *buf)
+{
+	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
+}
+EXPORT_SYMBOL_GPL(device_show_ulong);
+
+ssize_t device_store_int(struct device *dev,
+			 struct device_attribute *attr,
+			 const char *buf, size_t size)
+{
+	struct dev_ext_attribute *ea = to_ext_attr(attr);
+	char *end;
+	long new = simple_strtol(buf, &end, 0);
+	if (end == buf || new > INT_MAX || new < INT_MIN)
+		return -EINVAL;
+	*(int *)(ea->var) = new;
+	/* Always return full write size even if we didn't consume all */
+	return size;
+}
+EXPORT_SYMBOL_GPL(device_store_int);
+
+ssize_t device_show_int(struct device *dev,
+			struct device_attribute *attr,
+			char *buf)
+{
+	struct dev_ext_attribute *ea = to_ext_attr(attr);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
+}
+EXPORT_SYMBOL_GPL(device_show_int);
 
 /**
  *	device_release - free device structure.
@@ -463,7 +513,7 @@ static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
 static struct device_attribute devt_attr =
 	__ATTR(dev, S_IRUGO, show_dev, NULL);
 
-/* kset to create /sys/devices/  */
+/* /sys/devices/ */
 struct kset *devices_kset;
 
 /**
@@ -710,6 +760,10 @@ static struct kobject *get_device_parent(struct device *dev,
 		return k;
 	}
 
+	/* subsystems can specify a default root directory for their devices */
+	if (!parent && dev->bus && dev->bus->dev_root)
+		return &dev->bus->dev_root->kobj;
+
 	if (parent)
 		return &parent->kobj;
 	return NULL;
@@ -730,14 +784,6 @@ static void cleanup_device_parent(struct device *dev)
 	cleanup_glue_dir(dev, dev->kobj.parent);
 }
 
-static void setup_parent(struct device *dev, struct device *parent)
-{
-	struct kobject *kobj;
-	kobj = get_device_parent(dev, parent);
-	if (kobj)
-		dev->kobj.parent = kobj;
-}
-
 static int device_add_class_symlinks(struct device *dev)
 {
 	int error;
@@ -890,6 +936,7 @@ int device_private_init(struct device *dev)
 int device_add(struct device *dev)
 {
 	struct device *parent = NULL;
+	struct kobject *kobj;
 	struct class_interface *class_intf;
 	int error = -EINVAL;
 
@@ -913,6 +960,10 @@ int device_add(struct device *dev)
 		dev->init_name = NULL;
 	}
 
+	/* subsystems can specify simple device enumeration */
+	if (!dev_name(dev) && dev->bus && dev->bus->dev_name)
+		dev_set_name(dev, "%s%u", dev->bus->dev_name, dev->id);
+
 	if (!dev_name(dev)) {
 		error = -EINVAL;
 		goto name_error;
@@ -921,7 +972,9 @@ int device_add(struct device *dev)
 	pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
 
 	parent = get_device(dev->parent);
-	setup_parent(dev, parent);
+	kobj = get_device_parent(dev, parent);
+	if (kobj)
+		dev->kobj.parent = kobj;
 
 	/* use parent numa_node */
 	if (parent)
@@ -981,17 +1034,17 @@ int device_add(struct device *dev)
 			       &parent->p->klist_children);
 
 	if (dev->class) {
-		mutex_lock(&dev->class->p->class_mutex);
+		mutex_lock(&dev->class->p->mutex);
 		/* tie the class to the device */
 		klist_add_tail(&dev->knode_class,
 			       &dev->class->p->klist_devices);
 
 		/* notify any interfaces that the device is here */
 		list_for_each_entry(class_intf,
-				    &dev->class->p->class_interfaces, node)
+				    &dev->class->p->interfaces, node)
 			if (class_intf->add_dev)
 				class_intf->add_dev(dev, class_intf);
-		mutex_unlock(&dev->class->p->class_mutex);
+		mutex_unlock(&dev->class->p->mutex);
 	}
 done:
 	put_device(dev);
@@ -1106,15 +1159,15 @@ void device_del(struct device *dev)
 	if (dev->class) {
 		device_remove_class_symlinks(dev);
 
-		mutex_lock(&dev->class->p->class_mutex);
+		mutex_lock(&dev->class->p->mutex);
 		/* notify any interfaces that the device is now gone */
 		list_for_each_entry(class_intf,
-				    &dev->class->p->class_interfaces, node)
+				    &dev->class->p->interfaces, node)
 			if (class_intf->remove_dev)
 				class_intf->remove_dev(dev, class_intf);
 		/* remove the device from the class list */
 		klist_del(&dev->knode_class);
-		mutex_unlock(&dev->class->p->class_mutex);
+		mutex_unlock(&dev->class->p->mutex);
 	}
 	device_remove_file(dev, &uevent_attr);
 	device_remove_attrs(dev);