[PATCH] ivi-shell: bugfix, list of surfaces on a layer are cumulated when set render order is called several time in one commitchanges.
Pekka Paalanen
ppaalanen at gmail.com
Fri Aug 14 05:43:29 PDT 2015
On Wed, 5 Aug 2015 16:00:57 +0900
Nobuhiko Tanibata <nobuhiko_tanibata at xddp.denso.co.jp> wrote:
> The final list of surfaces of set render order shall be applied. So link
> of surfaces and list of surfaces in a layer shall be initialized. And
> then the order of surfaces shall be restructured.
>
> Signed-off-by: Nobuhiko Tanibata <nobuhiko_tanibata at xddp.denso.co.jp>
> ---
> ivi-shell/ivi-layout.c | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/ivi-shell/ivi-layout.c b/ivi-shell/ivi-layout.c
> index bb175b0..2b61ff2 100644
> --- a/ivi-shell/ivi-layout.c
> +++ b/ivi-shell/ivi-layout.c
> @@ -2082,14 +2082,14 @@ ivi_layout_layer_set_render_order(struct ivi_layout_layer *ivilayer,
> return IVI_FAILED;
> }
>
> - if (pSurface == NULL) {
> - wl_list_for_each_safe(ivisurf, next, &ivilayer->pending.surface_list, pending.link) {
> - if (!wl_list_empty(&ivisurf->pending.link)) {
> - wl_list_remove(&ivisurf->pending.link);
> - }
> + wl_list_for_each_safe(ivisurf, next,
> + &ivilayer->pending.surface_list, pending.link) {
> + wl_list_init(&ivisurf->pending.link);
> + }
>
> - wl_list_init(&ivisurf->pending.link);
> - }
> + wl_list_init(&ivilayer->pending.surface_list);
Hi,
heh, I don't recall seeing this code pattern before. It looks fragile
or even dangerous, because it is init'ing a link that is part of a
list, and doing that while traversing that list. However, I think it is
safe in this case, because:
- wl_list_for_each_safe protects against removal of the current item by
fetching the pointer to the next item before-hand, so init'ing rather
than removing the current item is still ok, and
- the whole list is always processed through, and finally the list head
is init'd, so all involved pointers are reset.
I've been using another pattern, e.g. src/rpi-renderer.c:1768
while (!wl_list_empty(&output->view_cleanup_list)) {
view = container_of(output->view_cleanup_list.next,
struct rpir_view, link);
rpir_view_destroy(view);
}
I'm not sure if we should prefer one or the other, because I'm
obviously biased in my judgement. :-)
The latter one does not involve temporarily broken list structures...
> +
> + if (pSurface == NULL || number ==0) {
> ivilayer->event_mask |= IVI_NOTIFICATION_REMOVE;
> return IVI_SUCCEEDED;
> }
Reviewed-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
Thanks,
pq
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