Re: [Qemu-devel] [PATCH v2 01/16] io: store reference to thread information in the QIOTask struct

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

On Wed, Jan 23, 2019 at 6:27 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
>
> Currently the struct QIOTaskThreadData is only needed by the worker
> thread, but a subsequent patch will need to access it from another
> context.
>
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

> ---
>  io/task.c | 53 ++++++++++++++++++++++++++++-------------------------
>  1 file changed, 28 insertions(+), 25 deletions(-)
>
> diff --git a/io/task.c b/io/task.c
> index 2886a2c1bc..d100a754d3 100644
> --- a/io/task.c
> +++ b/io/task.c
> @@ -24,6 +24,14 @@
>  #include "qemu/thread.h"
>  #include "trace.h"
>
> +struct QIOTaskThreadData {
> +    QIOTaskWorker worker;
> +    gpointer opaque;
> +    GDestroyNotify destroy;
> +    GMainContext *context;
> +};
> +
> +
>  struct QIOTask {
>      Object *source;
>      QIOTaskFunc func;
> @@ -32,6 +40,7 @@ struct QIOTask {
>      Error *err;
>      gpointer result;
>      GDestroyNotify destroyResult;
> +    struct QIOTaskThreadData *thread;
>  };
>
>
> @@ -72,31 +81,23 @@ static void qio_task_free(QIOTask *task)
>  }
>
>
> -struct QIOTaskThreadData {
> -    QIOTask *task;
> -    QIOTaskWorker worker;
> -    gpointer opaque;
> -    GDestroyNotify destroy;
> -    GMainContext *context;
> -};
> -
> -
>  static gboolean qio_task_thread_result(gpointer opaque)
>  {
> -    struct QIOTaskThreadData *data = opaque;
> +    QIOTask *task = opaque;
>
> -    trace_qio_task_thread_result(data->task);
> -    qio_task_complete(data->task);
> +    trace_qio_task_thread_result(task);
> +    qio_task_complete(task);
>
> -    if (data->destroy) {
> -        data->destroy(data->opaque);
> +    if (task->thread->destroy) {
> +        task->thread->destroy(task->thread->opaque);
>      }
>
> -    if (data->context) {
> -        g_main_context_unref(data->context);
> +    if (task->thread->context) {
> +        g_main_context_unref(task->thread->context);
>      }
>
> -    g_free(data);
> +    g_free(task->thread);
> +    task->thread = NULL;
>
>      return FALSE;
>  }
> @@ -104,22 +105,23 @@ static gboolean qio_task_thread_result(gpointer opaque)
>
>  static gpointer qio_task_thread_worker(gpointer opaque)
>  {
> -    struct QIOTaskThreadData *data = opaque;
> +    QIOTask *task = opaque;
>      GSource *idle;
>
> -    trace_qio_task_thread_run(data->task);
> -    data->worker(data->task, data->opaque);
> +    trace_qio_task_thread_run(task);
> +
> +    task->thread->worker(task, task->thread->opaque);
>
>      /* We're running in the background thread, and must only
>       * ever report the task results in the main event loop
>       * thread. So we schedule an idle callback to report
>       * the worker results
>       */
> -    trace_qio_task_thread_exit(data->task);
> +    trace_qio_task_thread_exit(task);
>
>      idle = g_idle_source_new();
> -    g_source_set_callback(idle, qio_task_thread_result, data, NULL);
> -    g_source_attach(idle, data->context);
> +    g_source_set_callback(idle, qio_task_thread_result, task, NULL);
> +    g_source_attach(idle, task->thread->context);
>
>      return NULL;
>  }
> @@ -138,17 +140,18 @@ void qio_task_run_in_thread(QIOTask *task,
>          g_main_context_ref(context);
>      }
>
> -    data->task = task;
>      data->worker = worker;
>      data->opaque = opaque;
>      data->destroy = destroy;
>      data->context = context;
>
> +    task->thread = data;
> +
>      trace_qio_task_thread_start(task, worker, opaque);
>      qemu_thread_create(&thread,
>                         "io-task-worker",
>                         qio_task_thread_worker,
> -                       data,
> +                       task,
>                         QEMU_THREAD_DETACHED);
>  }
>
> --
> 2.20.1
>