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Message-ID: <ed444e22-5eeb-444d-5164-a67be2b55bd5@opensource.wdc.com>
Date:   Fri, 12 Aug 2022 11:24:26 -0700
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Subject: Re: [PATCH 0/6] libsas and drivers: NCQ error handling
Content-Language: en-US
To:     John Garry <john.garry@huawei.com>, jejb@linux.ibm.com,
        martin.petersen@oracle.com, jinpu.wang@cloud.ionos.com,
        yangxingui@huawei.com, chenxiang66@hisilicon.com, hare@suse.de
Cc:     linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1658489049-232850-1-git-send-email-john.garry@huawei.com>
 <d2e27cb7-d90a-2f0a-1848-e1ec8faf7899@opensource.wdc.com>
 <437abe43-7ddd-6f49-9386-d8ed04c659bf@huawei.com>
 <15bfd5e0-7fcd-fdee-a546-7720b55eb108@opensource.wdc.com>
 <34bdd9a8-26bf-95b0-ed62-a6af5db05654@huawei.com>
From:   Damien Le Moal <damien.lemoal@opensource.wdc.com>
Organization: Western Digital Research
In-Reply-To: <34bdd9a8-26bf-95b0-ed62-a6af5db05654@huawei.com>
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On 2022/08/12 9:33, John Garry wrote:
> On 12/08/2022 16:39, Damien Le Moal wrote:
>>> For this specific test we don't seem to run a hardreset after the
>>> autopsy, but we do seem to be getting an NCQ error. That's interesting.
>>>
>>> We have noticed this scenario for hisi_sas NCQ error, whereby the
>>> autopsy decided a reset is not required or useful, such as a medium
>>> error. Anyway the pm8001 driver relies on the reset being run always for
>>> the NCQ error. So I am thinking of tweaking sas_ata_link_abort() as follows:
>>>
>>> void sas_ata_link_abort(struct domain_device *device)
>>> {
>>> 	struct ata_port *ap = device->sata_dev.ap;
>>> 	struct ata_link *link = &ap->link;
>>>
>>> 	link->eh_info.err_mask |= AC_ERR_DEV;
>>> +	link->eh_info.action |= ATA_EH_RESET;
>>> 	ata_link_abort(link);
>>> }
>>>
>>> This should force a reset.
>> This is an unaligned write to a sequential write required zone on SMR. So
>> definitely not worth a reset. Forcing hard resetting the link for such error is
>> an overkill. I think it is better to let ata_link_abort() -> ... -> scsi & ata
>> EH decide on the disposition.
> 
> Do you know if this triggered the pm8001 IO_XFER_ERROR_ABORTED_NCQ_MODE 
>   error?
> 
> If I do not set ATA_EH_RESET then I need to trust that libata will 
> always decide to do the reset for pm8001 IO_XFER_ERROR_ABORTED_NCQ_MODE 
> error. That is because it is in the reset that I send the pm8001 "abort 
> all" command - I could not find a better place for it.

Not sure what error it was. Will need to add a print of it to check. Easy to do.

> 
>>
>> Note that patch 3 did not apply cleanly to the current Linus tree. So a rebase
>> for the series is needed.
>>
> 
> That might be just git am, which always seems temperamental. The patches 
> still apply from cherry-pick'ing for me. Anyway, I'll send a new version 
> next week.

Yes, it was a "bad ancestor" thing. Direct patching worked just fine.

> 
> Thanks,
> John
> 


-- 
Damien Le Moal
Western Digital Research