Revert "HID: fix HID device resource race between HID core and debugging support"

This reverts commit 377c4c7 which is
commit fc43e9c upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I80bbce6f594ca4dd9b58d58598d4191112ea095f
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

Author: gregkh

drivers/hid/hid-core.c

@@ -708,22 +708,15 @@ static void hid_close_report(struct hid_device *device)
  * Free a device structure, all reports, and all fields.
  */
 
-void hiddev_free(struct kref *ref)
+static void hid_device_release(struct device *dev)
 {
-	struct hid_device *hid = container_of(ref, struct hid_device, ref);
+	struct hid_device *hid = to_hid_device(dev);
 
 	hid_close_report(hid);
 	kfree(hid->dev_rdesc);
 	kfree(hid);
 }
 
-static void hid_device_release(struct device *dev)
-{
-	struct hid_device *hid = to_hid_device(dev);
-
-	kref_put(&hid->ref, hiddev_free);
-}
-
 /*
  * Fetch a report description item from the data stream. We support long
  * items, though they are not used yet.
@@ -2821,7 +2814,6 @@ struct hid_device *hid_allocate_device(void)
 	spin_lock_init(&hdev->debug_list_lock);
 	sema_init(&hdev->driver_input_lock, 1);
 	mutex_init(&hdev->ll_open_lock);
-	kref_init(&hdev->ref);
 
 	return hdev;
 }

drivers/hid/hid-debug.c

@@ -1132,7 +1132,6 @@ static int hid_debug_events_open(struct inode *inode, struct file *file)
 		goto out;
 	}
 	list->hdev = (struct hid_device *) inode->i_private;
-	kref_get(&list->hdev->ref);
 	file->private_data = list;
 	mutex_init(&list->read_mutex);
 
@@ -1225,8 +1224,6 @@ static int hid_debug_events_release(struct inode *inode, struct file *file)
 	list_del(&list->node);
 	spin_unlock_irqrestore(&list->hdev->debug_list_lock, flags);
 	kfifo_free(&list->hid_debug_fifo);
-
-	kref_put(&list->hdev->ref, hiddev_free);
 	kfree(list);
 
 	return 0;

include/linux/hid.h

@@ -656,16 +656,13 @@ struct hid_device {							/* device report descriptor */
 	struct list_head debug_list;
 	spinlock_t  debug_list_lock;
 	wait_queue_head_t debug_wait;
-	struct kref			ref;
 
 	unsigned int id;						/* system unique id */
 
 	ANDROID_KABI_USE(1, struct { __s32 battery_charge_status; u32 padding; });
 	ANDROID_KABI_RESERVE(2);
 };
 
-void hiddev_free(struct kref *ref);
-
 #define to_hid_device(pdev) \
 	container_of(pdev, struct hid_device, dev)