Bluetooth: Add second hci_request callback option for full skb

This patch adds a second possible callback for HCI requests where the
callback will receive the full skb of the last successfully completed
HCI command. This API is useful for cases where we want to use a request
to read some data and the existing hci_event.c handlers do not store it
e.g. in the hci_dev struct.

The reason the patch is a bit bigger than just adding the new API is
because the hci_req_cmd_complete() functions required some refactoring
to enable it: now hci_req_cmd_complete() is simply used to request the
callback pointers if any, and the actual calling of them happens from a
single place at the end of hci_event_packet(). The reason for this is
that we need to pass the original skb (without any skb_pull, etc
modifications done to it) and it's simplest to keep track of it within
the hci_event_packet() function.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

1 files changed, 52 insertions, 24 deletions

diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 87e5bee..7c69eb3 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -2731,17 +2731,19 @@ unlock:
 	hci_dev_unlock(hdev);
 }
 
-static void hci_cmd_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
+static void hci_cmd_complete_evt(struct hci_dev *hdev, struct sk_buff *skb,
+				 u16 *opcode, u8 *status,
+				 hci_req_complete_t *req_complete,
+				 hci_req_complete_skb_t *req_complete_skb)
 {
 	struct hci_ev_cmd_complete *ev = (void *) skb->data;
-	u8 status = skb->data[sizeof(*ev)];
-	__u16 opcode;
 
-	skb_pull(skb, sizeof(*ev));
+	*opcode = __le16_to_cpu(ev->opcode);
+	*status = skb->data[sizeof(*ev)];
 
-	opcode = __le16_to_cpu(ev->opcode);
+	skb_pull(skb, sizeof(*ev));
 
-	switch (opcode) {
+	switch (*opcode) {
 	case HCI_OP_INQUIRY_CANCEL:
 		hci_cc_inquiry_cancel(hdev, skb);
 		break;
@@ -3019,32 +3021,36 @@ static void hci_cmd_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 		break;
 
 	default:
-		BT_DBG("%s opcode 0x%4.4x", hdev->name, opcode);
+		BT_DBG("%s opcode 0x%4.4x", hdev->name, *opcode);
 		break;
 	}
 
-	if (opcode != HCI_OP_NOP)
+	if (*opcode != HCI_OP_NOP)
 		cancel_delayed_work(&hdev->cmd_timer);
 
 	if (ev->ncmd && !test_bit(HCI_RESET, &hdev->flags))
 		atomic_set(&hdev->cmd_cnt, 1);
 
-	hci_req_cmd_complete(hdev, opcode, status);
+	hci_req_cmd_complete(hdev, *opcode, *status, req_complete,
+			     req_complete_skb);
 
 	if (atomic_read(&hdev->cmd_cnt) && !skb_queue_empty(&hdev->cmd_q))
 		queue_work(hdev->workqueue, &hdev->cmd_work);
 }
 
-static void hci_cmd_status_evt(struct hci_dev *hdev, struct sk_buff *skb)
+static void hci_cmd_status_evt(struct hci_dev *hdev, struct sk_buff *skb,
+			       u16 *opcode, u8 *status,
+			       hci_req_complete_t *req_complete,
+			       hci_req_complete_skb_t *req_complete_skb)
 {
 	struct hci_ev_cmd_status *ev = (void *) skb->data;
-	__u16 opcode;
 
 	skb_pull(skb, sizeof(*ev));
 
-	opcode = __le16_to_cpu(ev->opcode);
+	*opcode = __le16_to_cpu(ev->opcode);
+	*status = ev->status;
 
-	switch (opcode) {
+	switch (*opcode) {
 	case HCI_OP_INQUIRY:
 		hci_cs_inquiry(hdev, ev->status);
 		break;
@@ -3114,11 +3120,11 @@ static void hci_cmd_status_evt(struct hci_dev *hdev, struct sk_buff *skb)
 		break;
 
 	default:
-		BT_DBG("%s opcode 0x%4.4x", hdev->name, opcode);
+		BT_DBG("%s opcode 0x%4.4x", hdev->name, *opcode);
 		break;
 	}
 
-	if (opcode != HCI_OP_NOP)
+	if (*opcode != HCI_OP_NOP)
 		cancel_delayed_work(&hdev->cmd_timer);
 
 	if (ev->ncmd && !test_bit(HCI_RESET, &hdev->flags))
@@ -3132,7 +3138,8 @@ static void hci_cmd_status_evt(struct hci_dev *hdev, struct sk_buff *skb)
 	 */
 	if (ev->status ||
 	    (hdev->sent_cmd && !bt_cb(hdev->sent_cmd)->req.event))
-		hci_req_cmd_complete(hdev, opcode, ev->status);
+		hci_req_cmd_complete(hdev, *opcode, ev->status, req_complete,
+				     req_complete_skb);
 
 	if (atomic_read(&hdev->cmd_cnt) && !skb_queue_empty(&hdev->cmd_q))
 		queue_work(hdev->workqueue, &hdev->cmd_work);
@@ -5039,7 +5046,11 @@ static void hci_chan_selected_evt(struct hci_dev *hdev, struct sk_buff *skb)
 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_req_complete_t req_complete = NULL;
+	hci_req_complete_skb_t req_complete_skb = NULL;
+	struct sk_buff *orig_skb = NULL;
+	u8 status = 0, event = hdr->evt;
+	u16 opcode = HCI_OP_NOP;
 
 	hci_dev_lock(hdev);
 
@@ -5053,15 +5064,24 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 
 	hci_dev_unlock(hdev);
 
-	skb_pull(skb, HCI_EVENT_HDR_SIZE);
-
 	if (hdev->sent_cmd && bt_cb(hdev->sent_cmd)->req.event == event) {
 		struct hci_command_hdr *cmd_hdr = (void *) hdev->sent_cmd->data;
-		u16 opcode = __le16_to_cpu(cmd_hdr->opcode);
-
-		hci_req_cmd_complete(hdev, opcode, 0);
+		opcode = __le16_to_cpu(cmd_hdr->opcode);
+		hci_req_cmd_complete(hdev, opcode, status, &req_complete,
+				     &req_complete_skb);
 	}
 
+	/* If it looks like we might end up having to call
+	 * req_complete_skb, store a pristine copy of the skb since the
+	 * various handlers may modify the original one through
+	 * skb_pull() calls, etc.
+	 */
+	if (req_complete_skb || event == HCI_EV_CMD_STATUS ||
+	    event == HCI_EV_CMD_COMPLETE)
+		orig_skb = skb_clone(skb, GFP_KERNEL);
+
+	skb_pull(skb, HCI_EVENT_HDR_SIZE);
+
 	switch (event) {
 	case HCI_EV_INQUIRY_COMPLETE:
 		hci_inquiry_complete_evt(hdev, skb);
@@ -5104,11 +5124,13 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 		break;
 
 	case HCI_EV_CMD_COMPLETE:
-		hci_cmd_complete_evt(hdev, skb);
+		hci_cmd_complete_evt(hdev, skb, &opcode, &status,
+				     &req_complete, &req_complete_skb);
 		break;
 
 	case HCI_EV_CMD_STATUS:
-		hci_cmd_status_evt(hdev, skb);
+		hci_cmd_status_evt(hdev, skb, &opcode, &status, &req_complete,
+				   &req_complete_skb);
 		break;
 
 	case HCI_EV_HARDWARE_ERROR:
@@ -5240,6 +5262,12 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 		break;
 	}
 
+	if (req_complete)
+		req_complete(hdev, status, opcode);
+	else if (req_complete_skb)
+		req_complete_skb(hdev, status, opcode, orig_skb);
+
+	kfree_skb(orig_skb);
 	kfree_skb(skb);
 	hdev->stat.evt_rx++;
 }