HID: bt: Wait for ACK on Sent Reports

Wait for an ACK from the device before returning from
hidp_output_raw_report(). This way, failures can be returned to the user
application. Also, it prevents ACK/NAK packets from an output packet from
being confused with ACK/NAK packets from an input request packet.
Signed-off-by: Alan Ott <alan@signal11.us>
Acked-by: Gustavo F. Padovan <padovan@profusion.mobi>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

net/bluetooth/hidp/core.c

@@ -316,6 +316,9 @@ static int hidp_send_report(struct hidp_session *session, struct hid_report *rep
 static int hidp_output_raw_report(struct hid_device *hid, unsigned char *data, size_t count,
 		unsigned char report_type)
 {
+	struct hidp_session *session = hid->driver_data;
+	int ret;
+
 	switch (report_type) {
 	case HID_FEATURE_REPORT:
 		report_type = HIDP_TRANS_SET_REPORT | HIDP_DATA_RTYPE_FEATURE;
@@ -327,10 +330,47 @@ static int hidp_output_raw_report(struct hid_device *hid, unsigned char *data, s
 		return -EINVAL;
 	}
 
+	if (mutex_lock_interruptible(&session->report_mutex))
+		return -ERESTARTSYS;
+
+	/* Set up our wait, and send the report request to the device. */
+	set_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);
 	if (hidp_send_ctrl_message(hid->driver_data, report_type,
-			data, count))
-		return -ENOMEM;
-	return count;
+			data, count)) {
+		ret = -ENOMEM;
+		goto err;
+	}
+
+	/* Wait for the ACK from the device. */
+	while (test_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags)) {
+		int res;
+
+		res = wait_event_interruptible_timeout(session->report_queue,
+			!test_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags),
+			10*HZ);
+		if (res == 0) {
+			/* timeout */
+			ret = -EIO;
+			goto err;
+		}
+		if (res < 0) {
+			/* signal */
+			ret = -ERESTARTSYS;
+			goto err;
+		}
+	}
+
+	if (!session->output_report_success) {
+		ret = -EIO;
+		goto err;
+	}
+
+	ret = count;
+
+err:
+	clear_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);
+	mutex_unlock(&session->report_mutex);
+	return ret;
 }
 
 static void hidp_idle_timeout(unsigned long arg)
@@ -357,10 +397,12 @@ static void hidp_process_handshake(struct hidp_session *session,
 					unsigned char param)
 {
 	BT_DBG("session %p param 0x%02x", session, param);
+	session->output_report_success = 0; /* default condition */
 
 	switch (param) {
 	case HIDP_HSHK_SUCCESSFUL:
 		/* FIXME: Call into SET_ GET_ handlers here */
+		session->output_report_success = 1;
 		break;
 
 	case HIDP_HSHK_NOT_READY:
@@ -385,6 +427,12 @@ static void hidp_process_handshake(struct hidp_session *session,
 			HIDP_TRANS_HANDSHAKE | HIDP_HSHK_ERR_INVALID_PARAMETER, NULL, 0);
 		break;
 	}
+
+	/* Wake up the waiting thread. */
+	if (test_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags)) {
+		clear_bit(HIDP_WAITING_FOR_SEND_ACK, &session->flags);
+		wake_up_interruptible(&session->report_queue);
+	}
 }
 
 static void hidp_process_hid_control(struct hidp_session *session,

net/bluetooth/hidp/hidp.h

@@ -80,6 +80,7 @@
 #define HIDP_VIRTUAL_CABLE_UNPLUG	0
 #define HIDP_BOOT_PROTOCOL_MODE		1
 #define HIDP_BLUETOOTH_VENDOR_ID	9
+#define HIDP_WAITING_FOR_SEND_ACK	11
 
 struct hidp_connadd_req {
 	int   ctrl_sock;	// Connected control socket
@@ -154,6 +155,9 @@ struct hidp_session {
 	struct sk_buff_head ctrl_transmit;
 	struct sk_buff_head intr_transmit;
 
+	/* Used in hidp_output_raw_report() */
+	int output_report_success; /* boolean */
+
 	/* Report descriptor */
 	__u8 *rd_data;
 	uint rd_size;