Bluetooth: Track received events in hdev

This patch adds tracking of received HCI events to the hci_dev struct.
This is necessary so that a subsequent patch can implement a function
for sending a single command synchronously and returning the resulting
command complete parameters in the function return value.
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci_core.h

@@ -244,6 +244,7 @@ struct hci_dev {
 	struct sk_buff_head	raw_q;
 	struct sk_buff_head	cmd_q;
 
+	struct sk_buff		*recv_evt;
 	struct sk_buff		*sent_cmd;
 	struct sk_buff		*reassembly[NUM_REASSEMBLY];
 

net/bluetooth/hci_core.c

@@ -1136,6 +1136,9 @@ static int hci_dev_do_close(struct hci_dev *hdev)
 		hdev->sent_cmd = NULL;
 	}
 
+	kfree_skb(hdev->recv_evt);
+	hdev->recv_evt = NULL;
+
 	/* After this point our queues are empty
 	 * and no tasks are scheduled. */
 	hdev->close(hdev);

net/bluetooth/hci_event.c

@@ -3699,6 +3699,18 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 	struct hci_event_hdr *hdr = (void *) skb->data;
 	__u8 event = hdr->evt;
 
+	hci_dev_lock(hdev);
+
+	/* Received events are (currently) only needed when a request is
+	 * ongoing so avoid unnecessary memory allocation.
+	 */
+	if (hdev->req_status == HCI_REQ_PEND) {
+		kfree_skb(hdev->recv_evt);
+		hdev->recv_evt = skb_clone(skb, GFP_KERNEL);
+	}
+
+	hci_dev_unlock(hdev);
+
 	skb_pull(skb, HCI_EVENT_HDR_SIZE);
 
 	switch (event) {