drm/sched: Make sure we wait for all dependencies in kill_jobs_cb()

drm/sched: Make sure we wait for all dependencies in kill_jobs_cb()

drm_sched_entity_kill_jobs_cb() logic is omitting the last fence popped
from the dependency array that was waited upon before
drm_sched_entity_kill() was called (drm_sched_entity::dependency field),
so we're basically waiting for all dependencies except one.

In theory, this wait shouldn't be needed because resources should have
their users registered to the dma_resv object, thus guaranteeing that
future jobs wanting to access these resources wait on all the previous
users (depending on the access type, of course). But we want to keep
these explicit waits in the kill entity path just in case.

Let's make sure we keep all dependencies in the array in
drm_sched_job_dependency(), so we can iterate over the array and wait
in drm_sched_entity_kill_jobs_cb().

We also make sure we wait on drm_sched_fence::finished if we were
originally asked to wait on drm_sched_fence::scheduled. In that case,
we assume the intent was to delegate the wait to the firmware/GPU or
rely on the pipelining done at the entity/scheduler level, but when
killing jobs, we really want to wait for completion not just scheduling.

v2:
- Don't evict deps in drm_sched_job_dependency()

v3:
- Always wait for drm_sched_fence::finished fences in
  drm_sched_entity_kill_jobs_cb() when we see a sched_fence

v4:
- Fix commit message
- Fix a use-after-free bug

v5:
- Flag deps on which we should only wait for the scheduled event
  at insertion time

v6:
- Back to v4 implementation
- Add Christian's R-b

Cc: Frank Binns <frank.binns@imgtec.com>
Cc: Sarah Walker <sarah.walker@imgtec.com>
Cc: Donald Robson <donald.robson@imgtec.com>
Cc: Luben Tuikov <luben.tuikov@amd.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Suggested-by: "Christian König" <christian.koenig@amd.com>
Reviewed-by: "Christian König" <christian.koenig@amd.com>
Acked-by: Luben Tuikov <luben.tuikov@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230619071921.3465992-1-boris.brezillon@collabora.com