Bluetooth: Track both local and remote L2CAP fixed channel mask

To pave the way for future fixed channels to be added easily we should
track both the local and remote mask on a per-L2CAP connection (struct
l2cap_conn) basis. So far the code has used a global variable in a racy
way which anyway needs fixing.

This patch renames the existing conn->fixed_chan_mask that tracked
the remote mask to conn->remote_fixed_chan and adds a new variable
conn->local_fixed_chan to track the local mask. Since the HS support
info is now available in the local mask we can remove the
conn->hs_enabled variable.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/l2cap.h

@@ -619,8 +619,8 @@ struct l2cap_conn {
 	unsigned int		mtu;
 
 	__u32			feat_mask;
-	__u8			fixed_chan_mask;
-	bool			hs_enabled;
+	__u8			remote_fixed_chan;
+	__u8			local_fixed_chan;
 
 	__u8			info_state;
 	__u8			info_ident;

net/bluetooth/l2cap_core.c

@@ -46,7 +46,6 @@
 bool disable_ertm;
 
 static u32 l2cap_feat_mask = L2CAP_FEAT_FIXED_CHAN | L2CAP_FEAT_UCD;
-static u8 l2cap_fixed_chan[8] = { L2CAP_FC_SIG_BREDR | L2CAP_FC_CONNLESS, };
 
 static LIST_HEAD(chan_list);
 static DEFINE_RWLOCK(chan_list_lock);
@@ -1120,10 +1119,10 @@ static bool __amp_capable(struct l2cap_chan *chan)
 	struct hci_dev *hdev;
 	bool amp_available = false;
 
-	if (!conn->hs_enabled)
+	if (!(conn->local_fixed_chan & L2CAP_FC_A2MP))
 		return false;
 
-	if (!(conn->fixed_chan_mask & L2CAP_FC_A2MP))
+	if (!(conn->remote_fixed_chan & L2CAP_FC_A2MP))
 		return false;
 
 	read_lock(&hci_dev_list_lock);
@@ -3096,12 +3095,14 @@ static inline __u8 l2cap_select_mode(__u8 mode, __u16 remote_feat_mask)
 
 static inline bool __l2cap_ews_supported(struct l2cap_conn *conn)
 {
-	return conn->hs_enabled && conn->feat_mask & L2CAP_FEAT_EXT_WINDOW;
+	return ((conn->local_fixed_chan & L2CAP_FC_A2MP) &&
+		(conn->feat_mask & L2CAP_FEAT_EXT_WINDOW));
 }
 
 static inline bool __l2cap_efs_supported(struct l2cap_conn *conn)
 {
-	return conn->hs_enabled && conn->feat_mask & L2CAP_FEAT_EXT_FLOW;
+	return ((conn->local_fixed_chan & L2CAP_FC_A2MP) &&
+		(conn->feat_mask & L2CAP_FEAT_EXT_FLOW));
 }
 
 static void __l2cap_set_ertm_timeouts(struct l2cap_chan *chan,
@@ -3330,7 +3331,7 @@ static int l2cap_parse_conf_req(struct l2cap_chan *chan, void *data)
 			break;
 
 		case L2CAP_CONF_EWS:
-			if (!chan->conn->hs_enabled)
+			if (!(chan->conn->local_fixed_chan & L2CAP_FC_A2MP))
 				return -ECONNREFUSED;
 
 			set_bit(FLAG_EXT_CTRL, &chan->flags);
@@ -4334,7 +4335,7 @@ static inline int l2cap_information_req(struct l2cap_conn *conn,
 		if (!disable_ertm)
 			feat_mask |= L2CAP_FEAT_ERTM | L2CAP_FEAT_STREAMING
 				| L2CAP_FEAT_FCS;
-		if (conn->hs_enabled)
+		if (conn->local_fixed_chan & L2CAP_FC_A2MP)
 			feat_mask |= L2CAP_FEAT_EXT_FLOW
 				| L2CAP_FEAT_EXT_WINDOW;
 
@@ -4345,14 +4346,10 @@ static inline int l2cap_information_req(struct l2cap_conn *conn,
 		u8 buf[12];
 		struct l2cap_info_rsp *rsp = (struct l2cap_info_rsp *) buf;
 
-		if (conn->hs_enabled)
-			l2cap_fixed_chan[0] |= L2CAP_FC_A2MP;
-		else
-			l2cap_fixed_chan[0] &= ~L2CAP_FC_A2MP;
-
 		rsp->type   = cpu_to_le16(L2CAP_IT_FIXED_CHAN);
 		rsp->result = cpu_to_le16(L2CAP_IR_SUCCESS);
-		memcpy(rsp->data, l2cap_fixed_chan, sizeof(l2cap_fixed_chan));
+		rsp->data[0] = conn->local_fixed_chan;
+		memset(rsp->data + 1, 0, 7);
 		l2cap_send_cmd(conn, cmd->ident, L2CAP_INFO_RSP, sizeof(buf),
 			       buf);
 	} else {
@@ -4418,7 +4415,7 @@ static inline int l2cap_information_rsp(struct l2cap_conn *conn,
 		break;
 
 	case L2CAP_IT_FIXED_CHAN:
-		conn->fixed_chan_mask = rsp->data[0];
+		conn->remote_fixed_chan = rsp->data[0];
 		conn->info_state |= L2CAP_INFO_FEAT_MASK_REQ_DONE;
 		conn->info_ident = 0;
 
@@ -4442,7 +4439,7 @@ static int l2cap_create_channel_req(struct l2cap_conn *conn,
 	if (cmd_len != sizeof(*req))
 		return -EPROTO;
 
-	if (!conn->hs_enabled)
+	if (!(conn->local_fixed_chan & L2CAP_FC_A2MP))
 		return -EINVAL;
 
 	psm = le16_to_cpu(req->psm);
@@ -4872,7 +4869,7 @@ static inline int l2cap_move_channel_req(struct l2cap_conn *conn,
 
 	BT_DBG("icid 0x%4.4x, dest_amp_id %d", icid, req->dest_amp_id);
 
-	if (!conn->hs_enabled)
+	if (!(conn->local_fixed_chan & L2CAP_FC_A2MP))
 		return -EINVAL;
 
 	chan = l2cap_get_chan_by_dcid(conn, icid);
@@ -6964,9 +6961,11 @@ static struct l2cap_conn *l2cap_conn_add(struct hci_conn *hcon)
 
 	conn->feat_mask = 0;
 
-	if (hcon->type == ACL_LINK)
-		conn->hs_enabled = test_bit(HCI_HS_ENABLED,
-					    &hcon->hdev->dev_flags);
+	conn->local_fixed_chan = L2CAP_FC_SIG_BREDR | L2CAP_FC_CONNLESS;
+
+	if (hcon->type == ACL_LINK &&
+	    test_bit(HCI_HS_ENABLED, &hcon->hdev->dev_flags))
+		conn->local_fixed_chan |= L2CAP_FC_A2MP;
 
 	mutex_init(&conn->ident_lock);
 	mutex_init(&conn->chan_lock);