drm/lima: check vm != NULL in lima_vm_put

No need to handle this check before calling lima_vm_put.
Tested-by: Bhushan Shah <bshah@kde.org>
Reviewed-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200421133551.31481-4-yuq825@gmail.com

drivers/gpu/drm/lima/lima_sched.c

@@ -252,8 +252,7 @@ static struct dma_fence *lima_sched_run_job(struct drm_sched_job *job)
 			lima_mmu_switch_vm(pipe->mmu[i], vm);
 	}
 
-	if (last_vm)
-		lima_vm_put(last_vm);
+	lima_vm_put(last_vm);
 
 	trace_lima_task_run(task);
 
@@ -416,9 +415,7 @@ static void lima_sched_timedout_job(struct drm_sched_job *job)
 			lima_mmu_page_fault_resume(pipe->mmu[i]);
 	}
 
-	if (pipe->current_vm)
-		lima_vm_put(pipe->current_vm);
-
+	lima_vm_put(pipe->current_vm);
 	pipe->current_vm = NULL;
 	pipe->current_task = NULL;
 

drivers/gpu/drm/lima/lima_vm.h

@@ -54,7 +54,8 @@ static inline struct lima_vm *lima_vm_get(struct lima_vm *vm)
 
 static inline void lima_vm_put(struct lima_vm *vm)
 {
-	kref_put(&vm->refcount, lima_vm_release);
+	if (vm)
+		kref_put(&vm->refcount, lima_vm_release);
 }
 
 void lima_vm_print(struct lima_vm *vm);