Re: [PATCH v1 04/12] f2fs: cache: introduce writeback thread

Hi Chao,

> cache_thread->cache_wb_task = kthread_run(f2fs_cache_writeback_kthread,
> 						sbi, "%s", name);
> if (IS_ERR(cache_thread->cache_wb_task))
> 	return PTR_ERR(cache_thread->cache_wb_task);

After `kthread_run()` returns an error pointer, `cache_wb_task` retains that
value.  The later startup and stop paths distinguish only NULL from non-NULL,
and the stop path passes a non-NULL value to `kthread_stop()`.

Is `cache_wb_task` expected to remain an error pointer after
`f2fs_start_cache_wb_thread()` returns an error?