Corrected thread problem causing some calls to hang for 25s
Since the connection lock is released for a short while in
_dbus_connection_acquire_io_path there can already be a method return
received by another thread. The fix is to do an extra check after the
I/O path has been aquired both.
Bug: 2881601
Dr No: jsh / eastham
Change-Id: I7d3567d850cc2f8150db5ac68cffeb79a9fe0a72
diff --git a/dbus/dbus-connection-internal.h b/dbus/dbus-connection-internal.h
index 94026a2..fb5e696 100644
--- a/dbus/dbus-connection-internal.h
+++ b/dbus/dbus-connection-internal.h
@@ -75,6 +75,7 @@
dbus_bool_t enabled);
DBusConnection* _dbus_connection_new_for_transport (DBusTransport *transport);
void _dbus_connection_do_iteration_unlocked (DBusConnection *connection,
+ DBusPendingCall *pending,
unsigned int flags,
int timeout_milliseconds);
void _dbus_connection_close_possibly_shared (DBusConnection *connection);
diff --git a/dbus/dbus-connection.c b/dbus/dbus-connection.c
index 6a3de5b..1ad054f 100644
--- a/dbus/dbus-connection.c
+++ b/dbus/dbus-connection.c
@@ -316,6 +316,8 @@
static DBusDispatchStatus _dbus_connection_flush_unlocked (DBusConnection *connection);
static void _dbus_connection_close_possibly_shared_and_unlock (DBusConnection *connection);
static dbus_bool_t _dbus_connection_get_is_connected_unlocked (DBusConnection *connection);
+static dbus_bool_t _dbus_connection_peek_for_reply_unlocked (DBusConnection *connection,
+ dbus_uint32_t client_serial);
static DBusMessageFilter *
_dbus_message_filter_ref (DBusMessageFilter *filter)
@@ -1113,14 +1115,22 @@
* you specify DBUS_ITERATION_BLOCK; in that case the function
* returns immediately.
*
+ * If pending is not NULL then a check is made if the pending call
+ * is completed after the io path has been required. If the call
+ * has been completed nothing is done. This must be done since
+ * the _dbus_connection_acquire_io_path releases the connection
+ * lock for a while.
+ *
* Called with connection lock held.
*
* @param connection the connection.
+ * @param pending the pending call that should be checked or NULL
* @param flags iteration flags.
* @param timeout_milliseconds maximum blocking time, or -1 for no limit.
*/
void
_dbus_connection_do_iteration_unlocked (DBusConnection *connection,
+ DBusPendingCall *pending,
unsigned int flags,
int timeout_milliseconds)
{
@@ -1136,8 +1146,22 @@
{
HAVE_LOCK_CHECK (connection);
- _dbus_transport_do_iteration (connection->transport,
- flags, timeout_milliseconds);
+ if ( (pending != NULL) && _dbus_pending_call_get_completed_unlocked(pending))
+ {
+ _dbus_verbose ("pending call completed while acquiring I/O path");
+ }
+ else if ( (pending != NULL) &&
+ _dbus_connection_peek_for_reply_unlocked (connection,
+ _dbus_pending_call_get_reply_serial_unlocked (pending)))
+ {
+ _dbus_verbose ("pending call completed while acquiring I/O path (reply found in queue)");
+ }
+ else
+ {
+ _dbus_transport_do_iteration (connection->transport,
+ flags, timeout_milliseconds);
+ }
+
_dbus_connection_release_io_path (connection);
}
@@ -1923,6 +1947,7 @@
* out immediately, and otherwise get them queued up
*/
_dbus_connection_do_iteration_unlocked (connection,
+ NULL,
DBUS_ITERATION_DO_WRITING,
-1);
@@ -2091,6 +2116,32 @@
return message;
}
+/*
+ * Peek the incoming queue to see if we got reply for a specific serial
+ */
+static dbus_bool_t
+_dbus_connection_peek_for_reply_unlocked (DBusConnection *connection,
+ dbus_uint32_t client_serial)
+{
+ DBusList *link;
+ HAVE_LOCK_CHECK (connection);
+
+ link = _dbus_list_get_first_link (&connection->incoming_messages);
+
+ while (link != NULL)
+ {
+ DBusMessage *reply = link->data;
+
+ if (dbus_message_get_reply_serial (reply) == client_serial)
+ {
+ _dbus_verbose ("%s reply to %d found in queue\n", _DBUS_FUNCTION_NAME, client_serial);
+ return TRUE;
+ }
+ link = _dbus_list_get_next_link (&connection->incoming_messages, link);
+ }
+
+ return FALSE;
+}
/* This is slightly strange since we can pop a message here without
* the dispatch lock.
@@ -2261,6 +2312,7 @@
/* Now we wait... */
/* always block at least once as we know we don't have the reply yet */
_dbus_connection_do_iteration_unlocked (connection,
+ pending,
DBUS_ITERATION_DO_READING |
DBUS_ITERATION_BLOCK,
timeout_milliseconds);
@@ -2332,6 +2384,7 @@
{
/* block again, we don't have the reply buffered yet. */
_dbus_connection_do_iteration_unlocked (connection,
+ pending,
DBUS_ITERATION_DO_READING |
DBUS_ITERATION_BLOCK,
timeout_milliseconds);
@@ -3228,6 +3281,7 @@
_dbus_verbose ("doing iteration in %s\n", _DBUS_FUNCTION_NAME);
HAVE_LOCK_CHECK (connection);
_dbus_connection_do_iteration_unlocked (connection,
+ NULL,
DBUS_ITERATION_DO_READING |
DBUS_ITERATION_DO_WRITING |
DBUS_ITERATION_BLOCK,
@@ -3309,6 +3363,7 @@
{
_dbus_verbose ("doing iteration in %s\n", _DBUS_FUNCTION_NAME);
_dbus_connection_do_iteration_unlocked (connection,
+ NULL,
DBUS_ITERATION_DO_READING |
DBUS_ITERATION_DO_WRITING |
DBUS_ITERATION_BLOCK,
