1 files changed, 53 insertions, 24 deletions

diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index 3f7a82f10fe9..4a633c1b6882 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -457,6 +457,9 @@ struct l2cap_chan *l2cap_chan_create(void)
 	/* Set default lock nesting level */
 	atomic_set(&chan->nesting, L2CAP_NESTING_NORMAL);
 
+	/* Available receive buffer space is initially unknown */
+	chan->rx_avail = -1;
+
 	write_lock(&chan_list_lock);
 	list_add(&chan->global_l, &chan_list);
 	write_unlock(&chan_list_lock);
@@ -538,6 +541,28 @@ void l2cap_chan_set_defaults(struct l2cap_chan *chan)
 }
 EXPORT_SYMBOL_GPL(l2cap_chan_set_defaults);
 
+static __u16 l2cap_le_rx_credits(struct l2cap_chan *chan)
+{
+	size_t sdu_len = chan->sdu ? chan->sdu->len : 0;
+
+	if (chan->mps == 0)
+		return 0;
+
+	/* If we don't know the available space in the receiver buffer, give
+	 * enough credits for a full packet.
+	 */
+	if (chan->rx_avail == -1)
+		return (chan->imtu / chan->mps) + 1;
+
+	/* If we know how much space is available in the receive buffer, give
+	 * out as many credits as would fill the buffer.
+	 */
+	if (chan->rx_avail <= sdu_len)
+		return 0;
+
+	return DIV_ROUND_UP(chan->rx_avail - sdu_len, chan->mps);
+}
+
 static void l2cap_le_flowctl_init(struct l2cap_chan *chan, u16 tx_credits)
 {
 	chan->sdu = NULL;
@@ -546,8 +571,7 @@ static void l2cap_le_flowctl_init(struct l2cap_chan *chan, u16 tx_credits)
 	chan->tx_credits = tx_credits;
 	/* Derive MPS from connection MTU to stop HCI fragmentation */
 	chan->mps = min_t(u16, chan->imtu, chan->conn->mtu - L2CAP_HDR_SIZE);
-	/* Give enough credits for a full packet */
-	chan->rx_credits = (chan->imtu / chan->mps) + 1;
+	chan->rx_credits = l2cap_le_rx_credits(chan);
 
 	skb_queue_head_init(&chan->tx_q);
 }
@@ -559,7 +583,7 @@ static void l2cap_ecred_init(struct l2cap_chan *chan, u16 tx_credits)
 	/* L2CAP implementations shall support a minimum MPS of 64 octets */
 	if (chan->mps < L2CAP_ECRED_MIN_MPS) {
 		chan->mps = L2CAP_ECRED_MIN_MPS;
-		chan->rx_credits = (chan->imtu / chan->mps) + 1;
+		chan->rx_credits = l2cap_le_rx_credits(chan);
 	}
 }
 
@@ -3906,7 +3930,7 @@ static inline int l2cap_command_rej(struct l2cap_conn *conn,
 }
 
 static void l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd,
-			  u8 *data, u8 rsp_code, u8 amp_id)
+			  u8 *data, u8 rsp_code)
 {
 	struct l2cap_conn_req *req = (struct l2cap_conn_req *) data;
 	struct l2cap_conn_rsp rsp;
@@ -3985,17 +4009,8 @@ static void l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd,
 				status = L2CAP_CS_AUTHOR_PEND;
 				chan->ops->defer(chan);
 			} else {
-				/* Force pending result for AMP controllers.
-				 * The connection will succeed after the
-				 * physical link is up.
-				 */
-				if (amp_id == AMP_ID_BREDR) {
-					l2cap_state_change(chan, BT_CONFIG);
-					result = L2CAP_CR_SUCCESS;
-				} else {
-					l2cap_state_change(chan, BT_CONNECT2);
-					result = L2CAP_CR_PEND;
-				}
+				l2cap_state_change(chan, BT_CONNECT2);
+				result = L2CAP_CR_PEND;
 				status = L2CAP_CS_NO_INFO;
 			}
 		} else {
@@ -4060,7 +4075,7 @@ static int l2cap_connect_req(struct l2cap_conn *conn,
 		mgmt_device_connected(hdev, hcon, NULL, 0);
 	hci_dev_unlock(hdev);
 
-	l2cap_connect(conn, cmd, data, L2CAP_CONN_RSP, 0);
+	l2cap_connect(conn, cmd, data, L2CAP_CONN_RSP);
 	return 0;
 }
 
@@ -6513,9 +6528,7 @@ static void l2cap_chan_le_send_credits(struct l2cap_chan *chan)
 {
 	struct l2cap_conn *conn = chan->conn;
 	struct l2cap_le_credits pkt;
-	u16 return_credits;
-
-	return_credits = (chan->imtu / chan->mps) + 1;
+	u16 return_credits = l2cap_le_rx_credits(chan);
 
 	if (chan->rx_credits >= return_credits)
 		return;
@@ -6534,6 +6547,19 @@ static void l2cap_chan_le_send_credits(struct l2cap_chan *chan)
 	l2cap_send_cmd(conn, chan->ident, L2CAP_LE_CREDITS, sizeof(pkt), &pkt);
 }
 
+void l2cap_chan_rx_avail(struct l2cap_chan *chan, ssize_t rx_avail)
+{
+	if (chan->rx_avail == rx_avail)
+		return;
+
+	BT_DBG("chan %p has %zd bytes avail for rx", chan, rx_avail);
+
+	chan->rx_avail = rx_avail;
+
+	if (chan->state == BT_CONNECTED)
+		l2cap_chan_le_send_credits(chan);
+}
+
 static int l2cap_ecred_recv(struct l2cap_chan *chan, struct sk_buff *skb)
 {
 	int err;
@@ -6543,6 +6569,12 @@ static int l2cap_ecred_recv(struct l2cap_chan *chan, struct sk_buff *skb)
 	/* Wait recv to confirm reception before updating the credits */
 	err = chan->ops->recv(chan, skb);
 
+	if (err < 0 && chan->rx_avail != -1) {
+		BT_ERR("Queueing received LE L2CAP data failed");
+		l2cap_send_disconn_req(chan, ECONNRESET);
+		return err;
+	}
+
 	/* Update credits whenever an SDU is received */
 	l2cap_chan_le_send_credits(chan);
 
@@ -6565,7 +6597,8 @@ static int l2cap_ecred_data_rcv(struct l2cap_chan *chan, struct sk_buff *skb)
 	}
 
 	chan->rx_credits--;
-	BT_DBG("rx_credits %u -> %u", chan->rx_credits + 1, chan->rx_credits);
+	BT_DBG("chan %p: rx_credits %u -> %u",
+	       chan, chan->rx_credits + 1, chan->rx_credits);
 
 	/* Update if remote had run out of credits, this should only happens
 	 * if the remote is not using the entire MPS.
@@ -7453,10 +7486,6 @@ void l2cap_recv_acldata(struct hci_conn *hcon, struct sk_buff *skb, u16 flags)
 	struct l2cap_conn *conn = hcon->l2cap_data;
 	int len;
 
-	/* For AMP controller do not create l2cap conn */
-	if (!conn && hcon->hdev->dev_type != HCI_PRIMARY)
-		goto drop;
-
 	if (!conn)
 		conn = l2cap_conn_add(hcon);