[PATCH 2/5] drm/amdgpu: add separate last_clear tracking

[Christian König]

Add separate tracking of last cleared of freed mappings and use this as
dependency when freeing GEM handles.

Still heavily oversyncing, but better than undersyncing.

Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c |  4 ++--
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c  | 14 +++++++++-----
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h  |  3 ++-
 3 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index 2e16484bf606..4509a59d499a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -232,12 +232,12 @@ static void amdgpu_gem_object_close(struct drm_gem_object *obj,
 		fence = NULL;
 	}
 
-	r = amdgpu_vm_clear_freed(adev, vm, &fence);
+	r = amdgpu_vm_clear_freed(adev, vm, NULL);
+	fence = vm->last_clear;
 	if (r || !fence)
 		goto out_unlock;
 
 	amdgpu_bo_fence(bo, fence, true);
-	dma_fence_put(fence);
 
 out_unlock:
 	if (unlikely(r < 0))
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 11ebfef6962f..3f73e6097e6c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1286,15 +1286,17 @@ int amdgpu_vm_clear_freed(struct amdgpu_device *adev,
 		}
 	}
 
-	if (fence && f) {
+	if (!f)
+		return 0;
+
+	if (fence) {
 		dma_fence_put(*fence);
-		*fence = f;
-	} else {
-		dma_fence_put(f);
+		*fence = dma_fence_get(f);
 	}
 
+	swap(vm->last_clear, f);
+	dma_fence_put(f);
 	return 0;
-
 }
 
 /**
@@ -2084,6 +2086,7 @@ int amdgpu_vm_init(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 	else
 		vm->update_funcs = &amdgpu_vm_sdma_funcs;
 	vm->last_update = NULL;
+	vm->last_clear = NULL;
 	vm->last_unlocked = dma_fence_get_stub();
 
 	mutex_init(&vm->eviction_lock);
@@ -2198,6 +2201,7 @@ int amdgpu_vm_make_compute(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 		vm->update_funcs = &amdgpu_vm_sdma_funcs;
 	}
 	dma_fence_put(vm->last_update);
+	dma_fence_put(vm->last_clear);
 	vm->last_update = NULL;
 	vm->is_compute_context = true;
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index 1a814fbffff8..be82ef170926 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -272,12 +272,13 @@ struct amdgpu_vm {
 
 	/* BO mappings freed, but not yet updated in the PT */
 	struct list_head	freed;
+	struct dma_fence	*last_clear;
 
 	/* BOs which are invalidated, has been updated in the PTs */
 	struct list_head        done;
 
 	/* contains the page directory */
-	struct amdgpu_vm_bo_base     root;
+	struct amdgpu_vm_bo_base root;
 	struct dma_fence	*last_update;
 
 	/* Scheduler entities for page table updates */
-- 
2.25.1