On 04/11/2017 03:29 AM, Jan Kara wrote:
> When CFQ calls wbt_disable_default(), it will call
> blk_stat_remove_callback() to stop gathering IO statistics for the
> purposes of writeback throttling. Later, when request_queue is
> unregistered, wbt_exit() will call blk_stat_remove_callback() again
>
When CFQ calls wbt_disable_default(), it will call
blk_stat_remove_callback() to stop gathering IO statistics for the
purposes of writeback throttling. Later, when request_queue is
unregistered, wbt_exit() will call blk_stat_remove_callback() again
which will try to delete callback from the list ag