[PATCH v4 5/5] Bluetooth: hci_core: Detect if an ISO link has stalled

[Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx>]

From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx>

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 <luiz.von.dentz@xxxxxxxxx>
---
 include/net/bluetooth/hci.h      |  1 +
 include/net/bluetooth/hci_core.h |  1 +
 net/bluetooth/hci_core.c         | 34 ++++++++++++++++++++++++--------
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index df1847b74e55..9ecc70baaca9 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -488,6 +488,7 @@ enum {
 #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
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index b060a6a76456..242ff4033ac4 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -485,6 +485,7 @@ struct hci_dev {
 
 	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;
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index e2bffad9816f..4cf4bb1187dc 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -3585,24 +3585,37 @@ static void hci_prio_recalculate(struct hci_dev *hdev, __u8 type)
 
 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);
 }
 
@@ -3759,10 +3772,15 @@ static void hci_sched_iso(struct hci_dev *hdev, __u8 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)
-- 
2.50.1