drm/amdgpu: Fix double deletion of validate_list

If amdgpu_amdkfd_gpuvm_free_memory_of_gpu() fails after kgd_mem is
removed from validate_list, the mem handle still lingers in the KFD idr.
This means when process is terminated,
kfd_process_free_outstanding_kfd_bos() will call
amdgpu_amdkfd_gpuvm_free_memory_of_gpu() again resulting in double
deletion.

To avoid this -
 (a) Check if list is empty before deleting it
 (b) Rearragne amdgpu_amdkfd_gpuvm_free_memory_of_gpu() such that it can
     be safely called again if it returns failure the first time.

Signed-off-by: Harish Kasiviswanathan <[email protected]>
Reviewed-by: Philip Yang <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
(cherry picked from commit 6ba6034)

Author: hkasivis

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

@@ -1920,21 +1920,21 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
 
 	/* Make sure restore workers don't access the BO any more */
 	mutex_lock(&process_info->lock);
-	list_del(&mem->validate_list);
+	if (!list_empty(&mem->validate_list))
+		list_del_init(&mem->validate_list);
 	mutex_unlock(&process_info->lock);
 
+	ret = reserve_bo_and_cond_vms(mem, NULL, BO_VM_ALL, &ctx);
+	if (unlikely(ret))
+		return ret;
+
 	/* Cleanup user pages and MMU notifiers */
 	if (amdgpu_ttm_tt_get_usermm(mem->bo->tbo.ttm)) {
 		amdgpu_hmm_unregister(mem->bo);
-		mutex_lock(&process_info->notifier_lock);
 		amdgpu_hmm_range_free(mem->range);
-		mutex_unlock(&process_info->notifier_lock);
+		mem->range = NULL;
 	}
 
-	ret = reserve_bo_and_cond_vms(mem, NULL, BO_VM_ALL, &ctx);
-	if (unlikely(ret))
-		return ret;
-
 	amdgpu_amdkfd_remove_eviction_fence(mem->bo,
 					process_info->eviction_fence);
 	pr_debug("Release VA 0x%llx - 0x%llx\n", mem->va,