drm/i915: Add reference count to request structure

The plan is to use request structures everywhere that seqno values were
previously used. This means saving pointers to structures in places that used to
be simple integers. In turn, that means that the target structure now needs much
more stringent lifetime tracking. That is, it must not be freed while some other
random object still holds a pointer to it.

To achieve this tracking, a reference count needs to be added. Whenever a
pointer to the structure is saved away, the count must be incremented and the
free must only occur when all references have been released.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 9fe13075e5f..fbeaa3ad620 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1870,7 +1870,7 @@ void intel_cleanup_ring_buffer(struct intel_engine_cs *ring)
 
 	intel_unpin_ringbuffer_obj(ringbuf);
 	intel_destroy_ringbuffer_obj(ringbuf);
-	ring->preallocated_lazy_request = NULL;
+	i915_gem_request_assign(&ring->preallocated_lazy_request, NULL);
 	ring->outstanding_lazy_seqno = 0;
 
 	if (ring->cleanup)
@@ -2043,6 +2043,8 @@ intel_ring_alloc_seqno(struct intel_engine_cs *ring)
 	if (request == NULL)
 		return -ENOMEM;
 
+	kref_init(&request->ref);
+
 	ret = i915_gem_get_seqno(ring->dev, &ring->outstanding_lazy_seqno);
 	if (ret) {
 		kfree(request);