[PATCH BlueZ v1 04/10] adapter: Don't return Busy when a pending change sets the same value

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

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

Registering an agent sets the adapter bondable, so setting Pairable
right after, e.g. with "pairable on" in bluetoothctl as soon as it
registered its default agent, fails with Busy although the pending
change already does what was requested.

Track the value of pending changes, and when a request sets the same
value, reply to it once the pending change completed with its result,
without sending the command again. Opposing requests still fail with
Busy.

Fixes: 348feb005a12 ("adapter: Return Busy error when setting is pending")
Assisted-by: Claude:claude-opus-5-5
---
 src/adapter.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 77 insertions(+), 4 deletions(-)

diff --git a/src/adapter.c b/src/adapter.c
index edd2fdaf4db9..3c0895d1e241 100644
--- a/src/adapter.c
+++ b/src/adapter.c
@@ -280,6 +280,8 @@ struct btd_adapter {
 	char *short_name;		/* controller short name */
 	uint32_t supported_settings;	/* controller supported settings */
 	uint32_t pending_settings;	/* pending controller settings */
+	uint32_t pending_values;	/* values of pending settings */
+	struct queue *pending_props;	/* requests waiting a pending setting */
 	uint32_t power_state;		/* the power state */
 	uint32_t current_settings;	/* current controller settings */
 
@@ -745,6 +747,44 @@ struct set_mode_data {
 	uint8_t value;
 };
 
+struct pending_prop {
+	uint32_t setting;
+	GDBusPendingPropertySet id;
+	uint8_t status;
+};
+
+static bool reply_pending_prop(const void *data, const void *match_data)
+{
+	const struct pending_prop *prop = data;
+	const struct pending_prop *done = match_data;
+
+	if (!(prop->setting & done->setting))
+		return false;
+
+	if (done->status == MGMT_STATUS_SUCCESS)
+		g_dbus_pending_property_success(prop->id);
+	else if (done->status == MGMT_STATUS_RFKILLED)
+		g_dbus_pending_property_error(prop->id,
+					ERROR_INTERFACE ".Blocked",
+					mgmt_errstr(done->status));
+	else
+		g_dbus_pending_property_error(prop->id,
+					ERROR_INTERFACE ".Failed",
+					mgmt_errstr(done->status));
+
+	return true;
+}
+
+/* Reply to the requests that waited for a pending setting change */
+static void reply_pending_props(struct btd_adapter *adapter,
+					uint32_t setting, uint8_t status)
+{
+	struct pending_prop done = { .setting = setting, .status = status };
+
+	queue_remove_all(adapter->pending_props, reply_pending_prop, &done,
+									free);
+}
+
 static void set_mode_complete(uint8_t status, uint16_t length,
 					const void *param, void *user_data)
 {
@@ -761,6 +801,7 @@ static void set_mode_complete(uint8_t status, uint16_t length,
 		if (status != MGMT_STATUS_RFKILLED &&
 		    data->setting & MGMT_SETTING_POWERED)
 			reset_power_state_target(adapter, data->value);
+		reply_pending_props(adapter, data->setting, status);
 		return;
 	}
 
@@ -770,6 +811,7 @@ static void set_mode_complete(uint8_t status, uint16_t length,
 	 * event handling functions here.
 	 */
 	new_settings_callback(adapter->dev_id, length, param, adapter);
+	reply_pending_props(adapter, data->setting, status);
 }
 
 static void remove_temporary_devices(struct btd_adapter *adapter)
@@ -785,6 +827,17 @@ static void remove_temporary_devices(struct btd_adapter *adapter)
 	}
 }
 
+static void set_pending(struct btd_adapter *adapter, uint32_t setting,
+							uint8_t value)
+{
+	adapter->pending_settings |= setting;
+
+	if (value)
+		adapter->pending_values |= setting;
+	else
+		adapter->pending_values &= ~setting;
+}
+
 static bool set_mode(struct btd_adapter *adapter, uint16_t opcode,
 							uint8_t mode)
 {
@@ -828,7 +881,7 @@ static bool set_mode(struct btd_adapter *adapter, uint16_t opcode,
 	if (mgmt_send(adapter->mgmt, opcode,
 				adapter->dev_id, sizeof(cp), &cp,
 				set_mode_complete, data, g_free) > 0) {
-		adapter->pending_settings |= setting;
+		set_pending(adapter, setting, mode);
 		return true;
 	}
 	g_free(data);
@@ -3149,6 +3202,7 @@ static void property_set_mode_complete(uint8_t status, uint16_t length,
 		if (status != MGMT_STATUS_RFKILLED &&
 		    data->setting & MGMT_SETTING_POWERED)
 			reset_power_state_target(adapter, data->value);
+		reply_pending_props(adapter, data->setting, status);
 		return;
 	}
 
@@ -3160,6 +3214,7 @@ static void property_set_mode_complete(uint8_t status, uint16_t length,
 	 * event handling functions here.
 	 */
 	new_settings_callback(adapter->dev_id, length, param, adapter);
+	reply_pending_props(adapter, data->setting, status);
 }
 
 static void clear_discoverable(struct btd_adapter *adapter)
@@ -3199,9 +3254,23 @@ static void property_set_mode(struct btd_adapter *adapter, uint32_t setting,
 
 	dbus_message_iter_get_basic(value, &enable);
 
+	/* A pending change, e.g. bondable set when an agent registers,
+	 * already does what is requested if it sets the same value: reply
+	 * once it completed instead of sending the command again.
+	 */
 	if (adapter->pending_settings & setting) {
-		g_dbus_pending_property_error(id, ERROR_INTERFACE ".Busy",
-						NULL);
+		struct pending_prop *prop;
+
+		if (!!(adapter->pending_values & setting) != !!enable) {
+			g_dbus_pending_property_error(id,
+						ERROR_INTERFACE ".Busy", NULL);
+			return;
+		}
+
+		prop = new0(struct pending_prop, 1);
+		prop->setting = setting;
+		prop->id = id;
+		queue_push_tail(adapter->pending_props, prop);
 		return;
 	}
 
@@ -3289,7 +3358,7 @@ static void property_set_mode(struct btd_adapter *adapter, uint32_t setting,
 
 	if (mgmt_send(adapter->mgmt, opcode, adapter->dev_id, len, param,
 			property_set_mode_complete, data, g_free) > 0) {
-		adapter->pending_settings |= setting;
+		set_pending(adapter, setting, mode);
 		return;
 	}
 
@@ -6244,6 +6313,9 @@ static void adapter_free(gpointer user_data)
 
 	queue_destroy(adapter->exp_pending, cancel_exp_pending);
 
+	reply_pending_props(adapter, UINT32_MAX, MGMT_STATUS_FAILED);
+	queue_destroy(adapter->pending_props, NULL);
+
 	/*
 	 * Unregister all handlers for this specific index since
 	 * the adapter bound to them is no longer valid.
@@ -7311,6 +7383,7 @@ static struct btd_adapter *btd_adapter_new(uint16_t index)
 	adapter->auths = g_queue_new();
 	adapter->exps = queue_new();
 	adapter->exp_pending = queue_new();
+	adapter->pending_props = queue_new();
 
 	return btd_adapter_ref(adapter);
 }
-- 
2.56.0