[PATCH v2] drm/amdgpu: Force signal hw_fences that are embedded in non-sched jobs

[YuBiao Wang]

v2: Add comments to clarify in the code.

[Why]
For engines not supporting soft reset, i.e. VCN, there will be a failed
ib test before mode 1 reset during asic reset. The fences in this case
are never signaled and next time when we try to free the sa_bo, kernel
will hang.

[How]
During pre_asic_reset, driver will clear job fences and afterwards the
fences' refcount will be reduced to 1. For drm_sched_jobs it will be
released in job_free_cb, and for non-sched jobs like ib_test, it's meant
to be released in sa_bo_free but only when the fences are signaled. So
we have to force signal the non_sched bad job's fence during
pre_asic_reset or the clear is not complete.

Signed-off-by: YuBiao Wang <YuBiao.Wang at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
index faff4a3f96e6..ad7c5b70c35a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c
@@ -673,6 +673,7 @@ void amdgpu_fence_driver_clear_job_fences(struct amdgpu_ring *ring)
 {
 	int i;
 	struct dma_fence *old, **ptr;
+	struct amdgpu_job *job;
 
 	for (i = 0; i <= ring->fence_drv.num_fences_mask; i++) {
 		ptr = &ring->fence_drv.fences[i];
@@ -680,6 +681,13 @@ void amdgpu_fence_driver_clear_job_fences(struct amdgpu_ring *ring)
 		if (old && old->ops == &amdgpu_job_fence_ops) {
 			RCU_INIT_POINTER(*ptr, NULL);
 			dma_fence_put(old);
+			/* For non-sched bad job, i.e. failed ib test, we need to force
+			 * signal it right here or we won't be able to track them in fence drv
+			 * and they will remain unsignaled during sa_bo free.
+			 */
+			job = container_of(old, struct amdgpu_job, hw_fence);
+			if (!job->base.s_fence && !dma_fence_is_signaled(old))
+				dma_fence_signal(old);
 		}
 	}
 }
-- 
2.25.1