Bluetooth: Add support hdev to allocate private data

This patch adds support hdev to allocate extra size for private data.
The size of private data is specified in the hdev_alloc_size(priv_size)
and the allocated buffer can be accessed with hci_get_priv(hdev).
Signed-off-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci_core.h

@@ -1224,10 +1224,21 @@ static inline void hci_set_drvdata(struct hci_dev *hdev, void *data)
 	dev_set_drvdata(&hdev->dev, data);
 }
 
+static inline void *hci_get_priv(struct hci_dev *hdev)
+{
+	return (char *)hdev + sizeof(*hdev);
+}
+
 struct hci_dev *hci_dev_get(int index);
 struct hci_dev *hci_get_route(bdaddr_t *dst, bdaddr_t *src, u8 src_type);
 
-struct hci_dev *hci_alloc_dev(void);
+struct hci_dev *hci_alloc_dev_priv(int sizeof_priv);
+
+static inline struct hci_dev *hci_alloc_dev(void)
+{
+	return hci_alloc_dev_priv(0);
+}
+
 void hci_free_dev(struct hci_dev *hdev);
 int hci_register_dev(struct hci_dev *hdev);
 void hci_unregister_dev(struct hci_dev *hdev);

net/bluetooth/hci_core.c

@@ -3751,11 +3751,18 @@ static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action,
 }
 
 /* Alloc HCI device */
-struct hci_dev *hci_alloc_dev(void)
+struct hci_dev *hci_alloc_dev_priv(int sizeof_priv)
 {
 	struct hci_dev *hdev;
+	unsigned int alloc_size;
 
-	hdev = kzalloc(sizeof(*hdev), GFP_KERNEL);
+	alloc_size = sizeof(*hdev);
+	if (sizeof_priv) {
+		/* Fixme: May need ALIGN-ment? */
+		alloc_size += sizeof_priv;
+	}
+
+	hdev = kzalloc(alloc_size, GFP_KERNEL);
 	if (!hdev)
 		return NULL;
 
@@ -3869,7 +3876,7 @@ struct hci_dev *hci_alloc_dev(void)
 
 	return hdev;
 }
-EXPORT_SYMBOL(hci_alloc_dev);
+EXPORT_SYMBOL(hci_alloc_dev_priv);
 
 /* Free HCI device */
 void hci_free_dev(struct hci_dev *hdev)