The original design of QIOTask was intended to simplify lifecycle management by automatically freeing it when the task was marked as complete. This overlooked the fact that when a QIOTask is used in combination with a GSource, there may be times when the source callback is never invoked. This is typically when a GSource is released before any I/O event arrives. In such cases it is not desirable to mark a QIOTask as complete, but it still needs to be freed. To satisfy this, the task must be released manually. Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com> --- include/io/task.h | 29 +++++++++++++++++++++-------- io/channel-tls.c | 4 ++++ io/channel-websock.c | 3 +++ io/task.c | 8 ++++++-- tests/unit/test-io-task.c | 26 ++++++++++++++++++++++++++ 5 files changed, 60 insertions(+), 10 deletions(-) diff --git a/include/io/task.h b/include/io/task.h index 0b5342ee84..98847f5994 100644 --- a/include/io/task.h +++ b/include/io/task.h @@ -96,7 +96,7 @@ typedef void (*QIOTaskWorker)(QIOTask *task, * 1000, * myobject_operation_timer, * task, - * NULL); + * qio_task_free); * } * </programlisting> * </example> @@ -138,9 +138,8 @@ typedef void (*QIOTaskWorker)(QIOTask *task, * the callback func 'myobject_operation_notify' shown * earlier to deal with the results. * - * Once this function returns false, object_unref will be called - * automatically on the task causing it to be released and the - * ref on QMyObject dropped too. + * Once this function returns FALSE, the task will be freed, + * causing it release the ref on QMyObject too. * * The QIOTask module can also be used to perform operations * in a background thread context, while still reporting the @@ -208,8 +207,8 @@ typedef void (*QIOTaskWorker)(QIOTask *task, * 'err' attribute in the task object to determine if * the operation was successful or not. * - * The returned task will be released when qio_task_complete() - * is invoked. + * The returned task must be released by calling + * qio_task_free() when no longer required. * * Returns: the task struct */ @@ -218,6 +217,19 @@ QIOTask *qio_task_new(Object *source, gpointer opaque, GDestroyNotify destroy); +/** + * qio_task_free: + * task: the task object to free + * + * Free the resources associated with the task. Typically + * the qio_task_complete() method will be called immediately + * before this to trigger the task callback, however, it is + * permissible to free the task in the case of cancellation. + * The destroy callback will be used to release the opaque + * data provided to qio_task_new(). + */ +void qio_task_free(QIOTask *task); + /** * qio_task_run_in_thread: * @task: the task struct @@ -268,8 +280,9 @@ void qio_task_wait_thread(QIOTask *task); * qio_task_complete: * @task: the task struct * - * Invoke the completion callback for @task and - * then free its memory. + * Invoke the completion callback for @task. This should typically + * only be invoked once on a task, and then qio_task_free() used + * to free it. */ void qio_task_complete(QIOTask *task); diff --git a/io/channel-tls.c b/io/channel-tls.c index b0cec27cb9..07274c12df 100644 --- a/io/channel-tls.c +++ b/io/channel-tls.c @@ -170,6 +170,7 @@ static void qio_channel_tls_handshake_task(QIOChannelTLS *ioc, trace_qio_channel_tls_handshake_fail(ioc); qio_task_set_error(task, err); qio_task_complete(task); + qio_task_free(task); return; } @@ -183,6 +184,7 @@ static void qio_channel_tls_handshake_task(QIOChannelTLS *ioc, trace_qio_channel_tls_credentials_allow(ioc); } qio_task_complete(task); + qio_task_free(task); } else { GIOCondition condition; QIOChannelTLSData *data = g_new0(typeof(*data), 1); @@ -270,11 +272,13 @@ static void qio_channel_tls_bye_task(QIOChannelTLS *ioc, QIOTask *task, trace_qio_channel_tls_bye_fail(ioc); qio_task_set_error(task, err); qio_task_complete(task); + qio_task_free(task); return; } if (status == QCRYPTO_TLS_BYE_COMPLETE) { qio_task_complete(task); + qio_task_free(task); return; } diff --git a/io/channel-websock.c b/io/channel-websock.c index d0929ba232..100faba6b3 100644 --- a/io/channel-websock.c +++ b/io/channel-websock.c @@ -545,6 +545,7 @@ static gboolean qio_channel_websock_handshake_send(QIOChannel *ioc, trace_qio_channel_websock_handshake_fail(ioc, error_get_pretty(err)); qio_task_set_error(task, err); qio_task_complete(task); + qio_task_free(task); wioc->hs_io_tag = 0; return FALSE; } @@ -561,6 +562,7 @@ static gboolean qio_channel_websock_handshake_send(QIOChannel *ioc, trace_qio_channel_websock_handshake_complete(ioc); qio_task_complete(task); } + qio_task_free(task); wioc->hs_io_tag = 0; return FALSE; } @@ -588,6 +590,7 @@ static gboolean qio_channel_websock_handshake_io(QIOChannel *ioc, trace_qio_channel_websock_handshake_fail(ioc, error_get_pretty(err)); qio_task_set_error(task, err); qio_task_complete(task); + qio_task_free(task); wioc->hs_io_tag = 0; return FALSE; } diff --git a/io/task.c b/io/task.c index da79d31782..c3615d2d74 100644 --- a/io/task.c +++ b/io/task.c @@ -70,8 +70,12 @@ QIOTask *qio_task_new(Object *source, return task; } -static void qio_task_free(QIOTask *task) +void qio_task_free(QIOTask *task) { + if (!task) { + return; + } + qemu_mutex_lock(&task->thread_lock); if (task->thread) { if (task->thread->destroy) { @@ -108,6 +112,7 @@ static gboolean qio_task_thread_result(gpointer opaque) trace_qio_task_thread_result(task); qio_task_complete(task); + qio_task_free(task); return FALSE; } @@ -194,7 +199,6 @@ void qio_task_complete(QIOTask *task) { task->func(task, task->opaque); trace_qio_task_complete(task); - qio_task_free(task); } diff --git a/tests/unit/test-io-task.c b/tests/unit/test-io-task.c index 115dba8970..b1c8ecb7ab 100644 --- a/tests/unit/test-io-task.c +++ b/tests/unit/test-io-task.c @@ -73,6 +73,7 @@ static void test_task_complete(void) src = qio_task_get_source(task); qio_task_complete(task); + qio_task_free(task); g_assert(obj == src); @@ -84,6 +85,28 @@ static void test_task_complete(void) } +static void test_task_cancel(void) +{ + QIOTask *task; + Object *obj = object_new(TYPE_DUMMY); + Object *src; + struct TestTaskData data = { NULL, NULL, false }; + + task = qio_task_new(obj, task_callback, &data, NULL); + src = qio_task_get_source(task); + + qio_task_free(task); + + g_assert(obj == src); + + object_unref(obj); + + g_assert(data.source == NULL); + g_assert(data.err == NULL); + g_assert(data.freed == false); +} + + static void task_data_free(gpointer opaque) { struct TestTaskData *data = opaque; @@ -101,6 +124,7 @@ static void test_task_data_free(void) task = qio_task_new(obj, task_callback, &data, task_data_free); qio_task_complete(task); + qio_task_free(task); object_unref(obj); @@ -123,6 +147,7 @@ static void test_task_failure(void) qio_task_set_error(task, err); qio_task_complete(task); + qio_task_free(task); object_unref(obj); @@ -260,6 +285,7 @@ int main(int argc, char **argv) module_call_init(MODULE_INIT_QOM); type_register_static(&dummy_info); g_test_add_func("/crypto/task/complete", test_task_complete); + g_test_add_func("/crypto/task/cancel", test_task_cancel); g_test_add_func("/crypto/task/datafree", test_task_data_free); g_test_add_func("/crypto/task/failure", test_task_failure); g_test_add_func("/crypto/task/thread_complete", test_task_thread_complete); -- 2.53.0