From: Jason Yan <yanaijie@huawei.com>
To: Cong Wang <xiyou.wangcong@gmail.com>, John Garry <john.garry@huawei.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>,
LKML <linux-kernel@vger.kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Praveen Murali <pmurali@logicube.com>,
"James E.J. Bottomley" <jejb@linux.vnet.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
chenxiang <chenxiang66@hisilicon.com>
Subject: Re: [PATCH] libsas: flush pending destruct work in sas_unregister_domain_devices()
Date: Fri, 8 Dec 2017 15:54:54 +0800 [thread overview]
Message-ID: <5A2A454E.6050108@huawei.com> (raw)
In-Reply-To: <CAM_iQpVWmeq5BMvxJmD2FP6Zm6s7O05+NqzYQ6uCAp7iE1asnw@mail.gmail.com>
On 2017/12/8 6:57, Cong Wang wrote:
> On Thu, Dec 7, 2017 at 5:37 AM, John Garry <john.garry@huawei.com> 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.
>
We have sent a patchset to fix this and to enhance libsas hotplug.
Please refer to https://lkml.org/lkml/2017/9/6/142
And I'm going to send a new version soon.
Jason
>>
>> The device destruct takes place in a separate worker from which
>> sas_deform_port() is called, but the same queue. So we have this queued
>> destruct happen after the port is fully deformed -> hence the WARN.
>>
>> I guess you only tested your patch on disks attached through an expander.
>
> I have very limited scsi hardware, so my testing is limited too.
>
> .
>
next prev parent reply other threads:[~2017-12-08 7:56 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-28 0:24 [PATCH] libsas: flush pending destruct work in sas_unregister_domain_devices() Cong Wang
2017-11-28 8:20 ` Johannes Thumshirn
2017-11-28 11:18 ` John Garry
2017-11-28 17:04 ` Cong Wang
2017-12-07 13:37 ` John Garry
2017-12-07 22:57 ` Cong Wang
2017-12-08 0:40 ` Cong Wang
2017-12-08 1:04 ` Cong Wang
2017-12-08 7:54 ` Jason Yan [this message]
2017-12-09 19:51 ` Cong Wang
2017-11-28 17:00 ` Cong Wang
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