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From:   Pauli Virtanen <pav@iki.fi>
To:     linux-bluetooth@vger.kernel.org
Cc:     Pauli Virtanen <pav@iki.fi>
Subject: [PATCH BlueZ v2 2/2] bap: wait for CIG to become configurable before recreating CIS
Date:   Sun,  2 Jul 2023 21:43:05 +0300
Message-ID: <db38b1f94e45c0be70fcce66590ddbf4dcc705f9.1688323254.git.pav@iki.fi>
In-Reply-To: <09443d89e7486d890b346d47ebc5c6a8f5eb30af.1688323254.git.pav@iki.fi>
References: <09443d89e7486d890b346d47ebc5c6a8f5eb30af.1688323254.git.pav@iki.fi>
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ISO sockets cannot be reconnected before all sockets in the same CIG
have been closed, if the CIG was previously active.

Keep track which endpoints have active CIG, and postpone connecting CIS
until their CIG is no longer active.

This addresses getting EBUSY from connect() when multiple CIS in the
same CIG move streaming -> qos at the same time, which disconnects CIS
and recreates them.  The EBUSY originates from COMMAND_DISALLOWED
response to Set CIG Parameters.

This requires the kernel side do the Disconnect CIS / Remove CIG / Set
CIG Parameters HCI command steps in the right order, when all old
sockets are closed first before connecting new ones.
---

Notes:
    v2: no changes

 profiles/audio/bap.c | 107 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 97 insertions(+), 10 deletions(-)

diff --git a/profiles/audio/bap.c b/profiles/audio/bap.c
index 8e2fc1556..d7ce9e038 100644
--- a/profiles/audio/bap.c
+++ b/profiles/audio/bap.c
@@ -68,6 +68,7 @@ struct bap_ep {
 	GIOChannel *io;
 	unsigned int io_id;
 	bool recreate;
+	bool cig_active;
 	struct iovec *caps;
 	struct iovec *metadata;
 	struct bt_bap_qos qos;
@@ -525,6 +526,7 @@ static void bap_io_close(struct bap_ep *ep)
 
 	g_io_channel_unref(ep->io);
 	ep->io = NULL;
+	ep->cig_active = false;
 }
 
 static DBusMessage *set_configuration(DBusConnection *conn, DBusMessage *msg,
@@ -988,7 +990,7 @@ drop:
 	g_io_channel_shutdown(io, TRUE, NULL);
 }
 
-static void bap_accept_io(struct bap_data *data, struct bt_bap_stream *stream,
+static void bap_accept_io(struct bap_ep *ep, struct bt_bap_stream *stream,
 							int fd, int defer)
 {
 	char c;
@@ -1025,12 +1027,52 @@ static void bap_accept_io(struct bap_data *data, struct bt_bap_stream *stream,
 		}
 	}
 
+	ep->cig_active = true;
+
 	return;
 
 fail:
 	close(fd);
 }
 
+struct cig_busy_data {
+	struct btd_adapter *adapter;
+	uint8_t cig;
+};
+
+static bool cig_busy_ep(const void *data, const void *match_data)
+{
+	const struct bap_ep *ep = data;
+	const struct cig_busy_data *info = match_data;
+
+	return (ep->qos.ucast.cig_id == info->cig) && ep->cig_active;
+}
+
+static bool cig_busy_session(const void *data, const void *match_data)
+{
+	const struct bap_data *session = data;
+	const struct cig_busy_data *info = match_data;
+
+	if (device_get_adapter(session->device) != info->adapter)
+		return false;
+
+	return queue_find(session->snks, cig_busy_ep, match_data) ||
+			queue_find(session->srcs, cig_busy_ep, match_data);
+}
+
+static bool is_cig_busy(struct bap_data *data, uint8_t cig)
+{
+	struct cig_busy_data info;
+
+	if (cig == BT_ISO_QOS_CIG_UNSET)
+		return false;
+
+	info.adapter = device_get_adapter(data->device);
+	info.cig = cig;
+
+	return queue_find(sessions, cig_busy_session, &info);
+}
+
 static void bap_create_io(struct bap_data *data, struct bap_ep *ep,
 				struct bt_bap_stream *stream, int defer);
 
@@ -1047,6 +1089,48 @@ static gboolean bap_io_recreate(void *user_data)
 	return FALSE;
 }
 
+static void recreate_cig_ep(void *data, void *match_data)
+{
+	struct bap_ep *ep = (struct bap_ep *)data;
+	struct cig_busy_data *info = match_data;
+
+	if (ep->qos.ucast.cig_id != info->cig || !ep->recreate || ep->io_id)
+		return;
+
+	ep->recreate = false;
+	ep->io_id = g_idle_add(bap_io_recreate, ep);
+}
+
+static void recreate_cig_session(void *data, void *match_data)
+{
+	struct bap_data *session = data;
+	struct cig_busy_data *info = match_data;
+
+	if (device_get_adapter(session->device) != info->adapter)
+		return;
+
+	queue_foreach(session->snks, recreate_cig_ep, match_data);
+	queue_foreach(session->srcs, recreate_cig_ep, match_data);
+}
+
+static void recreate_cig(struct bap_ep *ep)
+{
+	struct bap_data *data = ep->data;
+	struct cig_busy_data info;
+
+	info.adapter = device_get_adapter(data->device);
+	info.cig = ep->qos.ucast.cig_id;
+
+	DBG("adapter %p ep %p recreate CIG %d", info.adapter, ep, info.cig);
+
+	if (ep->qos.ucast.cig_id == BT_ISO_QOS_CIG_UNSET) {
+		recreate_cig_ep(ep, &info);
+		return;
+	}
+
+	queue_foreach(sessions, recreate_cig_session, &info);
+}
+
 static gboolean bap_io_disconnected(GIOChannel *io, GIOCondition cond,
 							gpointer user_data)
 {
@@ -1059,10 +1143,8 @@ static gboolean bap_io_disconnected(GIOChannel *io, GIOCondition cond,
 	bap_io_close(ep);
 
 	/* Check if connecting recreate IO */
-	if (ep->recreate) {
-		ep->recreate = false;
-		ep->io_id = g_idle_add(bap_io_recreate, ep);
-	}
+	if (!is_cig_busy(ep->data, ep->qos.ucast.cig_id))
+		recreate_cig(ep);
 
 	return FALSE;
 }
@@ -1087,18 +1169,22 @@ static void bap_connect_io(struct bap_data *data, struct bap_ep *ep,
 	int fd;
 
 	/* If IO already set skip creating it again */
-	if (bt_bap_stream_get_io(stream))
+	if (bt_bap_stream_get_io(stream)) {
+		DBG("ep %p stream %p has existing io", ep, stream);
 		return;
+	}
 
 	if (bt_bap_stream_io_is_connecting(stream, &fd)) {
-		bap_accept_io(data, stream, fd, defer);
+		bap_accept_io(ep, stream, fd, defer);
 		return;
 	}
 
-	/* If IO channel still up wait for it to be disconnected and then
-	 * recreate.
+	/* If IO channel still up or CIG is busy, wait for it to be
+	 * disconnected and then recreate.
 	 */
-	if (ep->io) {
+	if (ep->io || is_cig_busy(data, ep->qos.ucast.cig_id)) {
+		DBG("ep %p stream %p defer %s wait recreate", ep, stream,
+						defer ? "true" : "false");
 		ep->recreate = true;
 		return;
 	}
@@ -1131,6 +1217,7 @@ static void bap_connect_io(struct bap_data *data, struct bap_ep *ep,
 						bap_io_disconnected, ep);
 
 	ep->io = io;
+	ep->cig_active = !defer;
 
 	bt_bap_stream_io_connecting(stream, g_io_channel_unix_get_fd(io));
 }
-- 
2.41.0