drm/amdgpu: stop using TTMs fault callback

Implement the fault handler ourself using the provided TTM functions.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/392324/

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

@@ -1341,19 +1341,14 @@ void amdgpu_bo_release_notify(struct ttm_buffer_object *bo)
  * Returns:
  * 0 for success or a negative error code on failure.
  */
-int amdgpu_bo_fault_reserve_notify(struct ttm_buffer_object *bo)
+vm_fault_t amdgpu_bo_fault_reserve_notify(struct ttm_buffer_object *bo)
 {
 	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->bdev);
 	struct ttm_operation_ctx ctx = { false, false };
-	struct amdgpu_bo *abo;
+	struct amdgpu_bo *abo = ttm_to_amdgpu_bo(bo);
 	unsigned long offset, size;
 	int r;
 
-	if (!amdgpu_bo_is_amdgpu_bo(bo))
-		return 0;
-
-	abo = ttm_to_amdgpu_bo(bo);
-
 	/* Remember that this BO was accessed by the CPU */
 	abo->flags |= AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED;
 
@@ -1367,7 +1362,7 @@ int amdgpu_bo_fault_reserve_notify(struct ttm_buffer_object *bo)
 
 	/* Can't move a pinned BO to visible VRAM */
 	if (abo->tbo.pin_count > 0)
-		return -EINVAL;
+		return VM_FAULT_SIGBUS;
 
 	/* hurrah the memory is not visible ! */
 	atomic64_inc(&adev->num_vram_cpu_page_faults);
@@ -1379,15 +1374,18 @@ int amdgpu_bo_fault_reserve_notify(struct ttm_buffer_object *bo)
 	abo->placement.busy_placement = &abo->placements[1];
 
 	r = ttm_bo_validate(bo, &abo->placement, &ctx);
-	if (unlikely(r != 0))
-		return r;
+	if (unlikely(r == -EBUSY || r == -ERESTARTSYS))
+		return VM_FAULT_NOPAGE;
+	else if (unlikely(r))
+		return VM_FAULT_SIGBUS;
 
 	offset = bo->mem.start << PAGE_SHIFT;
 	/* this should never happen */
 	if (bo->mem.mem_type == TTM_PL_VRAM &&
 	    (offset + size) > adev->gmc.visible_vram_size)
-		return -EINVAL;
+		return VM_FAULT_SIGBUS;
 
+	ttm_bo_move_to_lru_tail_unlocked(bo);
 	return 0;
 }
 

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

@@ -284,7 +284,7 @@ void amdgpu_bo_move_notify(struct ttm_buffer_object *bo,
 			   bool evict,
 			   struct ttm_resource *new_mem);
 void amdgpu_bo_release_notify(struct ttm_buffer_object *bo);
-int amdgpu_bo_fault_reserve_notify(struct ttm_buffer_object *bo);
+vm_fault_t amdgpu_bo_fault_reserve_notify(struct ttm_buffer_object *bo);
 void amdgpu_bo_fence(struct amdgpu_bo *bo, struct dma_fence *fence,
 		     bool shared);
 int amdgpu_bo_sync_wait_resv(struct amdgpu_device *adev, struct dma_resv *resv,

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

@@ -1708,7 +1708,6 @@ static struct ttm_bo_driver amdgpu_bo_driver = {
 	.verify_access = &amdgpu_verify_access,
 	.move_notify = &amdgpu_bo_move_notify,
 	.release_notify = &amdgpu_bo_release_notify,
-	.fault_reserve_notify = &amdgpu_bo_fault_reserve_notify,
 	.io_mem_reserve = &amdgpu_ttm_io_mem_reserve,
 	.io_mem_pfn = amdgpu_ttm_io_mem_pfn,
 	.access_memory = &amdgpu_ttm_access_memory,
@@ -2088,15 +2087,48 @@ void amdgpu_ttm_set_buffer_funcs_status(struct amdgpu_device *adev, bool enable)
 	adev->mman.buffer_funcs_enabled = enable;
 }
 
+static vm_fault_t amdgpu_ttm_fault(struct vm_fault *vmf)
+{
+	struct ttm_buffer_object *bo = vmf->vma->vm_private_data;
+	vm_fault_t ret;
+
+	ret = ttm_bo_vm_reserve(bo, vmf);
+	if (ret)
+		return ret;
+
+	ret = amdgpu_bo_fault_reserve_notify(bo);
+	if (ret)
+		goto unlock;
+
+	ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
+				       TTM_BO_VM_NUM_PREFAULT, 1);
+	if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
+		return ret;
+
+unlock:
+	dma_resv_unlock(bo->base.resv);
+	return ret;
+}
+
+static struct vm_operations_struct amdgpu_ttm_vm_ops = {
+	.fault = amdgpu_ttm_fault,
+	.open = ttm_bo_vm_open,
+	.close = ttm_bo_vm_close,
+	.access = ttm_bo_vm_access
+};
+
 int amdgpu_mmap(struct file *filp, struct vm_area_struct *vma)
 {
 	struct drm_file *file_priv = filp->private_data;
 	struct amdgpu_device *adev = drm_to_adev(file_priv->minor->dev);
+	int r;
 
-	if (adev == NULL)
-		return -EINVAL;
+	r = ttm_bo_mmap(filp, vma, &adev->mman.bdev);
+	if (unlikely(r != 0))
+		return r;
 
-	return ttm_bo_mmap(filp, vma, &adev->mman.bdev);
+	vma->vm_ops = &amdgpu_ttm_vm_ops;
+	return 0;
 }
 
 int amdgpu_copy_buffer(struct amdgpu_ring *ring, uint64_t src_offset,