[Intel-gfx] [PATCH 6/6] dma-fence: Store the timestamp in the same union as the cb_list

[Chris Wilson]

Quoting Koenig, Christian (2019-08-17 16:20:12)
> Am 17.08.19 um 16:47 schrieb Chris Wilson:
> > diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
> > index 89d96e3e6df6..2c21115b1a37 100644
> > --- a/drivers/dma-buf/dma-fence.c
> > +++ b/drivers/dma-buf/dma-fence.c
> > @@ -129,6 +129,7 @@ EXPORT_SYMBOL(dma_fence_context_alloc);
> >   int dma_fence_signal_locked(struct dma_fence *fence)
> >   {
> >       struct dma_fence_cb *cur, *tmp;
> > +     struct list_head cb_list;
> >   
> >       lockdep_assert_held(fence->lock);
> >   
> > @@ -136,16 +137,16 @@ int dma_fence_signal_locked(struct dma_fence *fence)
> >                                     &fence->flags)))
> >               return -EINVAL;
> >   
> > +     /* Stash the cb_list before replacing it with the timestamp */
> > +     list_replace(&fence->cb_list, &cb_list);
> 
> Stashing the timestamp instead is probably less bytes to modify.

My thinking was to pass the timestamp to the notify callbacks, we need
to stash the list and set the timestamp first.

Nothing that I'm aware of uses the timestamp (just the sync file debug
which weston was considering using at one point)... So I guess we don't
care? But I would say we should do that as a separate step in case
someone does.
-Chris