Re: [RFC] scsi: reduce protection of scan_mutex in scsi_remove_device

Song Liu
2017-04-21T22:32:32Z

> On Apr 21, 2017, at 2:20 PM, Bart Van Assche <Bart.VanAssche@sandisk.com> wrote:
>
> On Fri, 2017-04-21 at 14:13 -0700, Song Liu wrote:
>> On the other hand, some devices do long latency IO during deletion,
>> for example, sd_shutdown() may do sync cache and/or start_stop.
>> It is not necessary for these commands to run in series.
>
> Have you noticed my patch series that makes sd_shutdown() submit the
> SYNCHRONIZE CACHE command asynchronously? Have you tried whether that
> patch series would be a good alternative?
>
> Thanks,
>
> Bart.

The asynchronous SYNCHRONIZE CACHE will not help our use case, where the
latency comes from sd_start_stop_device(). Seems it is not easy to make
the START STOP UNIT command async.

Thanks,
Song