Re: [PATCH] libsas: flush pending destruct work in sas_unregister_domain_devices()

[Cong Wang]

On Thu, Dec 7, 2017 at 4:40 PM, Cong Wang <xiyou.wangcong@xxxxxxxxx> wrote:
> On Thu, Dec 7, 2017 at 2:57 PM, Cong Wang <xiyou.wangcong@xxxxxxxxx> wrote:
>> On Thu, Dec 7, 2017 at 5:37 AM, John Garry <john.garry@xxxxxxxxxx> wrote:
>>> On 28/11/2017 17:04, Cong Wang wrote:
>>>>
>>>> I don't understand, the only caller of sas_unregister_domain_devices()
>>>> is sas_deform_port().
>>>>
>>>
>>> And sas_deform_port() may be called from another worker on the same queue,
>>> right? As in sas_phye_loss_of_signal()->sas_deform_port()
>>
>> Oh, good catch! I didn't notice this subtle call path.
>>
>> Do you have any better idea to fix this? We saw this on 4.9 too.
>>
>
> I think we can just cancel the destruct work before calling
> sas_port_delete(). This should work even if it is called in
> another work.
>

This assumes sas_port_delete() could release resources recursively
in the hierarchy, this is true for sysfs but perhaps not true for other
resources...