[PATCH v2 1/2] drm/amdgpu: add optional fence out-parameter to amdgpu_vm_clear_freed

[Nicolai Hähnle]

From: Nicolai Hähnle <nicolai.haehnle at amd.com>

We will add the fence to freed buffer objects in a later commit, to ensure
that the underlying memory can only be re-used after all references in
page tables have been cleared.

Signed-off-by: Nicolai Hähnle <nicolai.haehnle at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c  |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c  | 21 +++++++++++++++------
 drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h  |  3 ++-
 4 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 55d553a..85e6070 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -778,21 +778,21 @@ static int amdgpu_bo_vm_update_pte(struct amdgpu_cs_parser *p)
 	int i, r;
 
 	r = amdgpu_vm_update_page_directory(adev, vm);
 	if (r)
 		return r;
 
 	r = amdgpu_sync_fence(adev, &p->job->sync, vm->page_directory_fence);
 	if (r)
 		return r;
 
-	r = amdgpu_vm_clear_freed(adev, vm);
+	r = amdgpu_vm_clear_freed(adev, vm, NULL);
 	if (r)
 		return r;
 
 	r = amdgpu_vm_bo_update(adev, fpriv->prt_va, false);
 	if (r)
 		return r;
 
 	r = amdgpu_sync_fence(adev, &p->job->sync,
 			      fpriv->prt_va->last_pt_update);
 	if (r)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index be9fb2c..4a53c43 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -535,21 +535,21 @@ static void amdgpu_gem_va_update_vm(struct amdgpu_device *adev,
 
 	r = amdgpu_vm_validate_pt_bos(adev, vm, amdgpu_gem_va_check,
 				      NULL);
 	if (r)
 		goto error;
 
 	r = amdgpu_vm_update_page_directory(adev, vm);
 	if (r)
 		goto error;
 
-	r = amdgpu_vm_clear_freed(adev, vm);
+	r = amdgpu_vm_clear_freed(adev, vm, NULL);
 	if (r)
 		goto error;
 
 	if (operation == AMDGPU_VA_OP_MAP ||
 	    operation == AMDGPU_VA_OP_REPLACE)
 		r = amdgpu_vm_bo_update(adev, bo_va, false);
 
 error:
 	if (r && r != -ERESTARTSYS)
 		DRM_ERROR("Couldn't update BO_VA (%d)\n", r);
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index dd7df45..2c95a75 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1397,48 +1397,57 @@ static void amdgpu_vm_prt_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
 	}
 
 	kfree(shared);
 }
 
 /**
  * amdgpu_vm_clear_freed - clear freed BOs in the PT
  *
  * @adev: amdgpu_device pointer
  * @vm: requested vm
+ * @fence: optional resulting fence (unchanged if no work needed to be done
+ * or if an error occurred)
  *
  * Make sure all freed BOs are cleared in the PT.
  * Returns 0 for success.
  *
  * PTs have to be reserved and mutex must be locked!
  */
 int amdgpu_vm_clear_freed(struct amdgpu_device *adev,
-			  struct amdgpu_vm *vm)
+			  struct amdgpu_vm *vm,
+			  struct fence **fence)
 {
 	struct amdgpu_bo_va_mapping *mapping;
-	struct fence *fence = NULL;
+	struct fence *f = NULL;
 	int r;
 
 	while (!list_empty(&vm->freed)) {
 		mapping = list_first_entry(&vm->freed,
 			struct amdgpu_bo_va_mapping, list);
 		list_del(&mapping->list);
 
 		r = amdgpu_vm_bo_split_mapping(adev, NULL, 0, NULL, vm, mapping,
-					       0, 0, &fence);
-		amdgpu_vm_free_mapping(adev, vm, mapping, fence);
+					       0, 0, &f);
+		amdgpu_vm_free_mapping(adev, vm, mapping, f);
 		if (r) {
-			fence_put(fence);
+			fence_put(f);
 			return r;
 		}
+	}
 
+	if (fence && f) {
+		fence_put(*fence);
+		*fence = f;
+	} else {
+		fence_put(f);
 	}
-	fence_put(fence);
+
 	return 0;
 
 }
 
 /**
  * amdgpu_vm_clear_invalids - clear invalidated BOs in the PT
  *
  * @adev: amdgpu_device pointer
  * @vm: requested vm
  *
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index ff10fa5..9d5a572 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -187,21 +187,22 @@ int amdgpu_vm_alloc_pts(struct amdgpu_device *adev,
 			struct amdgpu_vm *vm,
 			uint64_t saddr, uint64_t size);
 int amdgpu_vm_grab_id(struct amdgpu_vm *vm, struct amdgpu_ring *ring,
 		      struct amdgpu_sync *sync, struct fence *fence,
 		      struct amdgpu_job *job);
 int amdgpu_vm_flush(struct amdgpu_ring *ring, struct amdgpu_job *job);
 void amdgpu_vm_reset_id(struct amdgpu_device *adev, unsigned vm_id);
 int amdgpu_vm_update_page_directory(struct amdgpu_device *adev,
 				    struct amdgpu_vm *vm);
 int amdgpu_vm_clear_freed(struct amdgpu_device *adev,
-			  struct amdgpu_vm *vm);
+			  struct amdgpu_vm *vm,
+			  struct fence **fence);
 int amdgpu_vm_clear_invalids(struct amdgpu_device *adev, struct amdgpu_vm *vm,
 			     struct amdgpu_sync *sync);
 int amdgpu_vm_bo_update(struct amdgpu_device *adev,
 			struct amdgpu_bo_va *bo_va,
 			bool clear);
 void amdgpu_vm_bo_invalidate(struct amdgpu_device *adev,
 			     struct amdgpu_bo *bo);
 struct amdgpu_bo_va *amdgpu_vm_bo_find(struct amdgpu_vm *vm,
 				       struct amdgpu_bo *bo);
 struct amdgpu_bo_va *amdgpu_vm_bo_add(struct amdgpu_device *adev,
-- 
2.9.3