drm/amdgpu: add optional fence out-parameter to amdgpu_vm_clear_freed

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@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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 419fab50dc54..e83a6dcf2f68 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -785,7 +785,7 @@ static int amdgpu_bo_vm_update_pte(struct amdgpu_cs_parser *p)
         if (r)
                 return r;
 
-        r = amdgpu_vm_clear_freed(adev, vm);
+        r = amdgpu_vm_clear_freed(adev, vm, NULL);
         if (r)
                 return r;
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index c71c087727b8..5e068eefcaec 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -540,7 +540,7 @@ static void amdgpu_gem_va_update_vm(struct amdgpu_device *adev,
         if (r)
                 goto error;
 
-        r = amdgpu_vm_clear_freed(adev, vm);
+        r = amdgpu_vm_clear_freed(adev, vm, NULL);
         if (r)
                 goto error;
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 4fe892e3600d..696860132f04 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1382,6 +1382,8 @@ static void amdgpu_vm_prt_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
  *
  * @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.
@@ -1389,10 +1391,11 @@ static void amdgpu_vm_prt_fini(struct amdgpu_device *adev, struct amdgpu_vm *vm)
  * 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 dma_fence **fence)
 {
         struct amdgpu_bo_va_mapping *mapping;
-        struct dma_fence *fence = NULL;
+        struct dma_fence *f = NULL;
         int r;
 
         while (!list_empty(&vm->freed)) {
@@ -1401,15 +1404,21 @@ int amdgpu_vm_clear_freed(struct amdgpu_device *adev,
                 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) {
-                        dma_fence_put(fence);
+                        dma_fence_put(f);
                         return r;
                 }
+        }
 
+        if (fence && f) {
+                dma_fence_put(*fence);
+                *fence = f;
+        } else {
+                dma_fence_put(f);
         }
-        dma_fence_put(fence);
+
         return 0;
 
 }
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
index ab0429d12992..cbef85bef296 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
@@ -190,7 +190,8 @@ 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 dma_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,