[Bluetooth] Support concurrent connect requests

Most Bluetooth chips don't support concurrent connect requests, because
this would involve a multiple baseband page with only one radio. In the
case an upper layer like L2CAP requests a concurrent connect these chips
return the error "Command Disallowed" for the second request. If this
happens it the responsibility of the Bluetooth core to queue the request
and try again after the previous connect attempt has been completed.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci_core.h

@@ -153,6 +153,7 @@ struct hci_conn {
 	__u8             mode;
 	__u8		 type;
 	__u8		 out;
+	__u8		 attempt;
 	__u8		 dev_class[3];
 	__u8             features[8];
 	__u16            interval;
@@ -289,6 +290,22 @@ static inline struct hci_conn *hci_conn_hash_lookup_ba(struct hci_dev *hdev,
 	return NULL;
 }
 
+static inline struct hci_conn *hci_conn_hash_lookup_state(struct hci_dev *hdev,
+					__u8 type, __u16 state)
+{
+	struct hci_conn_hash *h = &hdev->conn_hash;
+	struct list_head *p;
+	struct hci_conn  *c;
+
+	list_for_each(p, &h->list) {
+		c = list_entry(p, struct hci_conn, list);
+		if (c->type == type && c->state == state)
+			return c;
+	}
+	return NULL;
+}
+
+void hci_acl_connect(struct hci_conn *conn);
 void hci_acl_disconn(struct hci_conn *conn, __u8 reason);
 void hci_add_sco(struct hci_conn *conn, __u16 handle);
 

net/bluetooth/af_bluetooth.c

@@ -48,7 +48,7 @@
 #define BT_DBG(D...)
 #endif
 
-#define VERSION "2.10"
+#define VERSION "2.11"
 
 /* Bluetooth sockets */
 #define BT_MAX_PROTO	8

net/bluetooth/hci_conn.c

@@ -51,7 +51,7 @@
 #define BT_DBG(D...)
 #endif
 
-static void hci_acl_connect(struct hci_conn *conn)
+void hci_acl_connect(struct hci_conn *conn)
 {
 	struct hci_dev *hdev = conn->hdev;
 	struct inquiry_entry *ie;
@@ -63,6 +63,8 @@ static void hci_acl_connect(struct hci_conn *conn)
 	conn->out   = 1;
 	conn->link_mode = HCI_LM_MASTER;
 
+	conn->attempt++;
+
 	memset(&cp, 0, sizeof(cp));
 	bacpy(&cp.bdaddr, &conn->dst);
 	cp.pscan_rep_mode = 0x02;

net/bluetooth/hci_event.c

@@ -414,9 +414,12 @@ static inline void hci_cs_create_conn(struct hci_dev *hdev, __u8 status)
 
 	if (status) {
 		if (conn && conn->state == BT_CONNECT) {
+			if (status != 0x0c || conn->attempt > 2) {
 				conn->state = BT_CLOSED;
 				hci_proto_connect_cfm(conn, status);
 				hci_conn_del(conn);
+			} else
+				conn->state = BT_CONNECT2;
 		}
 	} else {
 		if (!conn) {
@@ -728,7 +731,7 @@ static inline void hci_conn_request_evt(struct hci_dev *hdev, struct sk_buff *sk
 static inline void hci_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *skb)
 {
 	struct hci_ev_conn_complete *ev = (struct hci_ev_conn_complete *) skb->data;
-	struct hci_conn *conn;
+	struct hci_conn *conn, *pend;
 
 	BT_DBG("%s", hdev->name);
 
@@ -801,6 +804,10 @@ static inline void hci_conn_complete_evt(struct hci_dev *hdev, struct sk_buff *s
 	if (ev->status)
 		hci_conn_del(conn);
 
+	pend = hci_conn_hash_lookup_state(hdev, ACL_LINK, BT_CONNECT2);
+	if (pend)
+		hci_acl_connect(pend);
+
 	hci_dev_unlock(hdev);
 }