WARNING: Absolutely untested beyond "gcc isn't dying in agony".
Implicit fencing done properly needs to treat the implicit fencing
slots like a funny kind of IPC mailbox. In other words it needs to be
explicitly. This is the only way it will mesh well with explicit
fencing userspace like vk, and
Docs for struct dma_resv are fairly clear:
"A reservation object can have attached one exclusive fence (normally
associated with write operations) or N shared fences (read
operations)."
https://dri.freedesktop.org/docs/drm/driver-api/dma-buf.html#reservation-objects
Furthermore a review across
