Bluetooth: hci_core: Detect if an ISO link has stalled

This attempts to detect if an ISO link has been waiting for an ISO
buffer for longer than the maximum allowed transport latency then
proceed to use hci_link_tx_to which prints an error and disconnects.

Signed-off-by: Luiz Augusto von Dentz <[e-mail]>

include/net/bluetooth/hci.h

···
 #define HCI_AUTO_OFF_TIMEOUT	msecs_to_jiffies(2000)	/* 2 seconds */
 #define HCI_ACL_CONN_TIMEOUT	msecs_to_jiffies(20000)	/* 20 seconds */
 #define HCI_LE_CONN_TIMEOUT	msecs_to_jiffies(20000)	/* 20 seconds */
+#define HCI_ISO_TX_TIMEOUT	usecs_to_jiffies(0x7fffff) /* 8388607 usecs */
 
 /* HCI data types */
 #define HCI_COMMAND_PKT		0x01

include/net/bluetooth/hci_core.h

···
 
 	unsigned long	acl_last_tx;
 	unsigned long	le_last_tx;
+	unsigned long	iso_last_tx;
 
 	__u8		le_tx_def_phys;
 	__u8		le_rx_def_phys;

net/bluetooth/hci_core.c

···
 
 static void __check_timeout(struct hci_dev *hdev, unsigned int cnt, u8 type)
 {
-	unsigned long last_tx;
+	unsigned long timeout;
 
 	if (hci_dev_test_flag(hdev, HCI_UNCONFIGURED))
 		return;
 
 	switch (type) {
+	case ACL_LINK:
+		/* tx timeout must be longer than maximum link supervision
+		 * timeout (40.9 seconds)
+		 */
+		timeout = hdev->acl_last_tx + HCI_ACL_TX_TIMEOUT;
+		break;
 	case LE_LINK:
-		last_tx = hdev->le_last_tx;
+		/* tx timeout must be longer than maximum link supervision
+		 * timeout (40.9 seconds)
+		 */
+		timeout = hdev->le_last_tx + HCI_ACL_TX_TIMEOUT;
+		break;
+	case CIS_LINK:
+	case BIS_LINK:
+	case PA_LINK:
+		/* tx timeout must be longer than the maximum transport latency
+		 * (8.388607 seconds)
+		 */
+		timeout = hdev->iso_last_tx + HCI_ISO_TX_TIMEOUT;
 		break;
 	default:
-		last_tx = hdev->acl_last_tx;
-		break;
+		return;
 	}
 
-	/* tx timeout must be longer than maximum link supervision timeout
-	 * (40.9 seconds)
-	 */
-	if (!cnt && time_after(jiffies, last_tx + HCI_ACL_TX_TIMEOUT))
+	if (!cnt && time_after(jiffies, timeout))
 		hci_link_tx_to(hdev, type);
 }
 
···
 		return;
 
 	cnt = &hdev->iso_cnt;
+
+	__check_timeout(hdev, *cnt, type);
+
 	while (*cnt && (conn = hci_low_sent(hdev, type, &quote))) {
 		while (quote-- && (skb = skb_dequeue(&conn->data_q))) {
 			BT_DBG("skb %p len %d", skb, skb->len);
+
 			hci_send_conn_frame(hdev, conn, skb);
+			hdev->iso_last_tx = jiffies;
 
 			conn->sent++;
 			if (conn->sent == ~0)