drm/amdgpu: Get rid of amdgpu_job->external_hw_fence

This is a follow-up cleanup to [1]. See bellow refcount balancing
for calling amdgpu_job_submit_direct after this cleanup as far
as I calculated.

amdgpu_fence_emit
	dma_fence_init 1
	dma_fence_get(fence) 2
	rcu_assign_pointer(*ptr, dma_fence_get(fence) 3

---> amdgpu_job_submit_direct completes before fence signaled
			amdgpu_sa_bo_free
				(*sa_bo)->fence = dma_fence_get(fence) 4

			amdgpu_job_free
				dma_fence_put 3

			amdgpu_vcn_enc_get_destroy_msg
				*fence = dma_fence_get(f) 4
				dma_fence_put(f); 3

			amdgpu_vcn_enc_ring_test_ib
				dma_fence_put(fence) 2

			amdgpu_fence_process
				dma_fence_put 1

			amdgpu_sa_bo_remove_locked
				dma_fence_put 0

---> amdgpu_job_submit_direct completes after fence signaled
			amdgpu_fence_process
				dma_fence_put 2

			amdgpu_job_free
				dma_fence_put 1

			amdgpu_vcn_enc_get_destroy_msg
				*fence = dma_fence_get(f) 2
				dma_fence_put(f); 1

			amdgpu_vcn_enc_ring_test_ib
				dma_fence_put(fence) 0

[1] - https://patchwork.kernel.org/project/dri-devel/cover/20220624180955.485440-1-andrey.grodzovsky@amd.com/Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_device.c

@@ -5230,8 +5230,7 @@ int amdgpu_device_gpu_recover(struct amdgpu_device *adev,
 	 *
 	 * job->base holds a reference to parent fence
 	 */
-	if (job && (job->hw_fence.ops != NULL) &&
-	    dma_fence_is_signaled(&job->hw_fence)) {
+	if (job && dma_fence_is_signaled(&job->hw_fence)) {
 		job_signaled = true;
 		dev_info(adev->dev, "Guilty job already signaled, skipping HW reset");
 		goto skip_hw_reset;

drivers/gpu/drm/amd/amdgpu/amdgpu_job.c

@@ -133,16 +133,10 @@ void amdgpu_job_free_resources(struct amdgpu_job *job)
 {
 	struct amdgpu_ring *ring = to_amdgpu_ring(job->base.sched);
 	struct dma_fence *f;
-	struct dma_fence *hw_fence;
 	unsigned i;
 
-	if (job->hw_fence.ops == NULL)
-		hw_fence = job->external_hw_fence;
-	else
-		hw_fence = &job->hw_fence;
-
 	/* use sched fence if available */
-	f = job->base.s_fence ? &job->base.s_fence->finished : hw_fence;
+	f = job->base.s_fence ? &job->base.s_fence->finished :  &job->hw_fence;
 	for (i = 0; i < job->num_ibs; ++i)
 		amdgpu_ib_free(ring->adev, &job->ibs[i], f);
 }
@@ -156,11 +150,7 @@ static void amdgpu_job_free_cb(struct drm_sched_job *s_job)
 	amdgpu_sync_free(&job->sync);
 	amdgpu_sync_free(&job->sched_sync);
 
-    /* only put the hw fence if has embedded fence */
-	if (job->hw_fence.ops != NULL)
-		dma_fence_put(&job->hw_fence);
-	else
-		kfree(job);
+	dma_fence_put(&job->hw_fence);
 }
 
 void amdgpu_job_free(struct amdgpu_job *job)
@@ -169,11 +159,7 @@ void amdgpu_job_free(struct amdgpu_job *job)
 	amdgpu_sync_free(&job->sync);
 	amdgpu_sync_free(&job->sched_sync);
 
-	/* only put the hw fence if has embedded fence */
-	if (job->hw_fence.ops != NULL)
-		dma_fence_put(&job->hw_fence);
-	else
-		kfree(job);
+	dma_fence_put(&job->hw_fence);
 }
 
 int amdgpu_job_submit(struct amdgpu_job *job, struct drm_sched_entity *entity,
@@ -203,15 +189,12 @@ int amdgpu_job_submit_direct(struct amdgpu_job *job, struct amdgpu_ring *ring,
 	int r;
 
 	job->base.sched = &ring->sched;
-	r = amdgpu_ib_schedule(ring, job->num_ibs, job->ibs, NULL, fence);
-	/* record external_hw_fence for direct submit */
-	job->external_hw_fence = dma_fence_get(*fence);
+	r = amdgpu_ib_schedule(ring, job->num_ibs, job->ibs, job, fence);
+
 	if (r)
 		return r;
 
 	amdgpu_job_free(job);
-	dma_fence_put(*fence);
-
 	return 0;
 }
 

drivers/gpu/drm/amd/amdgpu/amdgpu_job.h

@@ -50,7 +50,6 @@ struct amdgpu_job {
 	struct amdgpu_sync	sync;
 	struct amdgpu_sync	sched_sync;
 	struct dma_fence	hw_fence;
-	struct dma_fence	*external_hw_fence;
 	uint32_t		preamble_status;
 	uint32_t                preemption_status;
 	bool                    vm_needs_flush;