1 files changed, 82 insertions, 1 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index ee0a51a3a41..be9aba4dc2f 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -27,6 +27,9 @@
 
 int (*platform_notify)(struct device *dev) = NULL;
 int (*platform_notify_remove)(struct device *dev) = NULL;
+static struct kobject *dev_kobj;
+struct kobject *sysfs_dev_char_kobj;
+struct kobject *sysfs_dev_block_kobj;
 
 #ifdef CONFIG_BLOCK
 static inline int device_is_not_partition(struct device *dev)
@@ -776,6 +779,54 @@ int dev_set_name(struct device *dev, const char *fmt, ...)
 EXPORT_SYMBOL_GPL(dev_set_name);
 
 /**
+ * device_to_dev_kobj - select a /sys/dev/ directory for the device
+ * @dev: device
+ *
+ * By default we select char/ for new entries.  Setting class->dev_obj
+ * to NULL prevents an entry from being created.  class->dev_kobj must
+ * be set (or cleared) before any devices are registered to the class
+ * otherwise device_create_sys_dev_entry() and
+ * device_remove_sys_dev_entry() will disagree about the the presence
+ * of the link.
+ */
+static struct kobject *device_to_dev_kobj(struct device *dev)
+{
+	struct kobject *kobj;
+
+	if (dev->class)
+		kobj = dev->class->dev_kobj;
+	else
+		kobj = sysfs_dev_char_kobj;
+
+	return kobj;
+}
+
+static int device_create_sys_dev_entry(struct device *dev)
+{
+	struct kobject *kobj = device_to_dev_kobj(dev);
+	int error = 0;
+	char devt_str[15];
+
+	if (kobj) {
+		format_dev_t(devt_str, dev->devt);
+		error = sysfs_create_link(kobj, &dev->kobj, devt_str);
+	}
+
+	return error;
+}
+
+static void device_remove_sys_dev_entry(struct device *dev)
+{
+	struct kobject *kobj = device_to_dev_kobj(dev);
+	char devt_str[15];
+
+	if (kobj) {
+		format_dev_t(devt_str, dev->devt);
+		sysfs_remove_link(kobj, devt_str);
+	}
+}
+
+/**
  * device_add - add device to device hierarchy.
  * @dev: device.
  *
@@ -829,6 +880,10 @@ int device_add(struct device *dev)
 		error = device_create_file(dev, &devt_attr);
 		if (error)
 			goto ueventattrError;
+
+		error = device_create_sys_dev_entry(dev);
+		if (error)
+			goto devtattrError;
 	}
 
 	error = device_add_class_symlinks(dev);
@@ -873,6 +928,9 @@ int device_add(struct device *dev)
 	device_remove_class_symlinks(dev);
  SymlinkError:
 	if (MAJOR(dev->devt))
+		device_remove_sys_dev_entry(dev);
+ devtattrError:
+	if (MAJOR(dev->devt))
 		device_remove_file(dev, &devt_attr);
  ueventattrError:
 	device_remove_file(dev, &uevent_attr);
@@ -948,8 +1006,10 @@ void device_del(struct device *dev)
 	device_pm_remove(dev);
 	if (parent)
 		klist_del(&dev->knode_parent);
-	if (MAJOR(dev->devt))
+	if (MAJOR(dev->devt)) {
+		device_remove_sys_dev_entry(dev);
 		device_remove_file(dev, &devt_attr);
+	}
 	if (dev->class) {
 		device_remove_class_symlinks(dev);
 
@@ -1074,7 +1134,25 @@ int __init devices_init(void)
 	devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
 	if (!devices_kset)
 		return -ENOMEM;
+	dev_kobj = kobject_create_and_add("dev", NULL);
+	if (!dev_kobj)
+		goto dev_kobj_err;
+	sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
+	if (!sysfs_dev_block_kobj)
+		goto block_kobj_err;
+	sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
+	if (!sysfs_dev_char_kobj)
+		goto char_kobj_err;
+
 	return 0;
+
+ char_kobj_err:
+	kobject_put(sysfs_dev_block_kobj);
+ block_kobj_err:
+	kobject_put(dev_kobj);
+ dev_kobj_err:
+	kset_unregister(devices_kset);
+	return -ENOMEM;
 }
 
 EXPORT_SYMBOL_GPL(device_for_each_child);
@@ -1447,4 +1525,7 @@ void device_shutdown(void)
 			dev->driver->shutdown(dev);
 		}
 	}
+	kobject_put(sysfs_dev_char_kobj);
+	kobject_put(sysfs_dev_block_kobj);
+	kobject_put(dev_kobj);
 }