[Mesa-dev] [PATCH v2 3/6] vulkan/wsi/wayland: Use per-display event queue

[Lionel Landwerlin]

On 05/05/17 17:47, Daniel Stone wrote:
> Calling random callbacks on the display's event queue is hostile, as
> we may call into client code when it least expects it. Create our own
> event queue, one per wsi_wl_display, and use that for the registry.
>
> Signed-off-by: Daniel Stone <daniels at collabora.com>
> Cc: mesa-stable at lists.freedesktop.org
> ---
>   src/vulkan/wsi/wsi_common_wayland.c | 44 +++++++++++++++++++++++++++----------
>   1 file changed, 32 insertions(+), 12 deletions(-)
>
> diff --git a/src/vulkan/wsi/wsi_common_wayland.c b/src/vulkan/wsi/wsi_common_wayland.c
> index 014ea13d65..c67ba089f9 100644
> --- a/src/vulkan/wsi/wsi_common_wayland.c
> +++ b/src/vulkan/wsi/wsi_common_wayland.c
> @@ -45,7 +45,11 @@
>   struct wsi_wayland;
>   
>   struct wsi_wl_display {
> -   struct wl_display *                          display;
> +   /* The real wl_display */
> +   struct wl_display *                          wl_display;
> +   /* Actually a proxy wrapper around the event queue */
> +   struct wl_display *                          wl_display_wrapper;
> +   struct wl_event_queue *                      queue;
>      struct wl_drm *                              drm;
>   
>      struct wsi_wayland *wsi_wl;
> @@ -250,6 +254,10 @@ wsi_wl_display_destroy(struct wsi_wayland *wsi, struct wsi_wl_display *display)
>      u_vector_finish(&display->formats);
>      if (display->drm)
>         wl_drm_destroy(display->drm);
> +   if (display->wl_display_wrapper)
> +      wl_proxy_wrapper_destroy(display->wl_display_wrapper);
> +   if (display->queue)
> +      wl_event_queue_destroy(display->queue);
>      vk_free(wsi->alloc, display);
>   }
>   
> @@ -264,26 +272,38 @@ wsi_wl_display_create(struct wsi_wayland *wsi, struct wl_display *wl_display)
>   
>      memset(display, 0, sizeof(*display));
>   
> -   display->display = wl_display;
>      display->wsi_wl = wsi;
> +   display->wl_display = wl_display;
>   
>      if (!u_vector_init(&display->formats, sizeof(VkFormat), 8))
>         goto fail;
>   
> -   struct wl_registry *registry = wl_display_get_registry(wl_display);
> +   display->queue = wl_display_create_queue(wl_display);
> +   if (!display->queue)
> +      goto fail;
> +
> +   display->wl_display_wrapper = wl_proxy_create_wrapper(wl_display);
> +   if (!display->wl_display_wrapper)
> +      goto fail;
> +
> +   wl_proxy_set_queue((struct wl_proxy *) display->wl_display_wrapper,
> +                      display->queue);
> +
> +   struct wl_registry *registry =
> +      wl_display_get_registry(display->wl_display_wrapper);
>      if (!registry)
>         goto fail;
>   
>      wl_registry_add_listener(registry, &registry_listener, display);
>   
> -   /* Round-rip to get the wl_drm global */
> -   wl_display_roundtrip(wl_display);
> +   /* Round-trip to get the wl_drm global */
> +   wl_display_roundtrip_queue(display->wl_display, display->queue);
>   
>      if (!display->drm)
>         goto fail_registry;
>   
> -   /* Round-rip to get wl_drm formats and capabilities */
> -   wl_display_roundtrip(wl_display);
> +   /* Round-trip to get wl_drm formats and capabilities */
> +   wl_display_roundtrip_queue(display->wl_display, display->queue);
>   
>      /* We need prime support */
>      if (!(display->capabilities & WL_DRM_CAPABILITY_PRIME))
> @@ -535,7 +555,7 @@ wsi_wl_swapchain_acquire_next_image(struct wsi_swapchain *wsi_chain,
>   {
>      struct wsi_wl_swapchain *chain = (struct wsi_wl_swapchain *)wsi_chain;
>   
> -   int ret = wl_display_dispatch_queue_pending(chain->display->display,
> +   int ret = wl_display_dispatch_queue_pending(chain->display->wl_display,
>                                                  chain->queue);

I'm not a wayland expert, so this might be a dumb question.
Why do you keep using chain->queue instead of chain->display->queue in a 
few places?

>      /* XXX: I'm not sure if out-of-date is the right error here.  If
>       * wl_display_dispatch_queue_pending fails it most likely means we got
> @@ -557,7 +577,7 @@ wsi_wl_swapchain_acquire_next_image(struct wsi_swapchain *wsi_chain,
>         /* This time we do a blocking dispatch because we can't go
>          * anywhere until we get an event.
>          */
> -      int ret = wl_display_roundtrip_queue(chain->display->display,
> +      int ret = wl_display_roundtrip_queue(chain->display->wl_display,
>                                              chain->queue);
>         if (ret < 0)
>            return VK_ERROR_OUT_OF_DATE_KHR;
> @@ -587,7 +607,7 @@ wsi_wl_swapchain_queue_present(struct wsi_swapchain *wsi_chain,
>   
>      if (chain->base.present_mode == VK_PRESENT_MODE_FIFO_KHR) {
>         while (!chain->fifo_ready) {
> -         int ret = wl_display_dispatch_queue(chain->display->display,
> +         int ret = wl_display_dispatch_queue(chain->display->wl_display,
>                                                chain->queue);
>            if (ret < 0)
>               return VK_ERROR_OUT_OF_DATE_KHR;
> @@ -619,7 +639,7 @@ wsi_wl_swapchain_queue_present(struct wsi_swapchain *wsi_chain,
>   
>      chain->images[image_index].busy = true;
>      wl_surface_commit(chain->surface);
> -   wl_display_flush(chain->display->display);
> +   wl_display_flush(chain->display->wl_display);
>   
>      return VK_SUCCESS;
>   }
> @@ -765,7 +785,7 @@ wsi_wl_surface_create_swapchain(VkIcdSurfaceBase *icd_surface,
>         goto fail;
>      }
>   
> -   chain->queue = wl_display_create_queue(chain->display->display);
> +   chain->queue = wl_display_create_queue(chain->display->wl_display);
>      if (!chain->queue) {
>         result = VK_ERROR_INITIALIZATION_FAILED;
>         goto fail;