vkd3d: Update the descriptor next index before getting a reference for writing.

Fixes a race condition where the descriptor is modified between getting
its object and resetting the `next` index. The new object would never be
written. While it is invalid for the app to write descriptors used by a
command list which has been submitted to a queue, unused descriptors may
be written. This change also supports writing descriptors in a worker
thread.
This commit is contained in:
Conor McCarthy 2023-07-30 13:25:56 +10:00 committed by Alexandre Julliard
parent 21491d1bbb
commit 70962ae7d8
Notes: Alexandre Julliard 2023-12-14 23:31:17 +01:00
Approved-by: Giovanni Mascellani (@giomasce)
Approved-by: Henri Verbeet (@hverbeet)
Approved-by: Alexandre Julliard (@julliard)
Merge-Request: https://gitlab.winehq.org/wine/vkd3d/-/merge_requests/292

View File

@ -2632,20 +2632,18 @@ void d3d12_desc_flush_vk_heap_updates_locked(struct d3d12_descriptor_heap *descr
for (; i != UINT_MAX; i = next)
{
src = &descriptors[i];
next = (int)src->next >> 1;
next = vkd3d_atomic_exchange(&src->next, 0);
next = (int)next >> 1;
/* A race exists here between updating src->next and getting the current object. The best
* we can do is get the object last, which may result in a harmless rewrite later. */
u.object = d3d12_desc_get_object_ref(src, device);
if (!u.object)
{
vkd3d_atomic_exchange(&src->next, 0);
continue;
}
writes.held_refs[writes.held_ref_count++] = u.object;
d3d12_desc_write_vk_heap(descriptor_heap, i, &writes, u.object, device);
vkd3d_atomic_exchange(&src->next, 0);
}
/* Avoid thunk calls wherever possible. */