From: wangyijing <wangyijing@huawei.com>
To: John Garry <john.garry@huawei.com>,
Dan Williams <dan.j.williams@intel.com>
Cc: <jejb@linux.vnet.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
linux-scsi <linux-scsi@vger.kernel.org>,
"John Garry" <john.garry2@mail.dcu.ie>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
<linuxarm@huawei.com>, <lindar_liu@usish.com>,
Tejun Heo <tj@kernel.org>,
Jinpu Wang <jinpu.wang@profitbricks.com>
Subject: Re: [RFC PATCH] scsi: libsas: fix WARN on device removal
Date: Wed, 23 Nov 2016 09:07:32 +0800 [thread overview]
Message-ID: <5834EBD4.5010104@huawei.com> (raw)
In-Reply-To: <96fb83c2-ef02-181c-b27d-bb4c3dbc8194@huawei.com>
>>
>> The events are not lost.
>
> In sas_queue_event(), if there is a particular event pending for a port/PHY, we cannot queue further same event types for that port/PHY. I think my colleagues found issue where we try to enqueue multiple complementary events.
Yes, we found this issue in our local tests.
>
>> The new problem this patch introduces is
>> delaying sas port deletion where it was previously immediate. So now
>> we can get into a situation where the port has gone down and can start
>> processing a port up event before the previous deletion work has run.
>>
>>>>
>>>>> And it's a very noisy warning, as in 6K lines on the console when an
>>>>> expander is unplugged.
>>>>
>>>>
>>>> Does something like this modulate the failure?
>>
>> I'm curious if we simply need to fix the double deletion of the
>> sas_port bsg queue, could you try the changes below?
>>
>
> No, I just tested it on a root port and we get the same WARN.
>
>>>>
>>>> diff --git a/drivers/scsi/scsi_transport_sas.c
>>>> b/drivers/scsi/scsi_transport_sas.c index
>>>> 60b651bfaa01..11401e5c88ba 100644
>>>> --- a/drivers/scsi/scsi_transport_sas.c
>>>> +++ b/drivers/scsi/scsi_transport_sas.c
>>>> @@ -262,9 +262,10 @@ static void sas_bsg_remove(struct Scsi_Host
>>>> *shost, struct sas_rphy *rphy
>>>> {
>>>> struct request_queue *q;
>>>>
>>>> - if (rphy)
>>>> + if (rphy) {
>>>> q = rphy->q;
>>>> - else
>>>> + rphy->q = NULL;
>>>> + } else
>>>> q = to_sas_host_attrs(shost)->q;
>>>>
>>>> if (!q)
>>>>
>>>> .
>>>>
>>>
>>>
>>
>> .
>>
>
>
>
> .
>
prev parent reply other threads:[~2016-11-23 1:11 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-03 14:58 [RFC PATCH] scsi: libsas: fix WARN on device removal John Garry
2016-11-09 12:28 ` John Garry
2016-11-09 17:36 ` John Garry
2016-11-09 19:09 ` Dan Williams
2016-11-09 20:35 ` Dan Williams
2016-11-10 11:53 ` John Garry
2016-11-11 8:12 ` wangyijing
2016-11-11 8:23 ` John Garry
2016-11-11 8:49 ` wangyijing
2016-11-17 15:23 ` John Garry
2016-11-18 1:51 ` Martin K. Petersen
2016-11-18 1:53 ` Dan Williams
2016-11-18 9:00 ` John Garry
2016-11-18 19:08 ` Dan Williams
2016-11-21 15:16 ` John Garry
2016-11-21 17:13 ` Dan Williams
2016-11-22 16:56 ` John Garry
2016-11-23 1:07 ` wangyijing [this message]
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