linux-kernel - Re: [PATCH 0/6] libsas and drivers: NCQ error handling

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Message-ID: <34bdd9a8-26bf-95b0-ed62-a6af5db05654@huawei.com>
Date:   Fri, 12 Aug 2022 17:33:57 +0100
From:   John Garry <john.garry@...wei.com>
To:     Damien Le Moal <damien.lemoal@...nsource.wdc.com>,
        <jejb@...ux.ibm.com>, <martin.petersen@...cle.com>,
        <jinpu.wang@...ud.ionos.com>, <yangxingui@...wei.com>,
        <chenxiang66@...ilicon.com>, <hare@...e.de>
CC:     <linux-scsi@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 0/6] libsas and drivers: NCQ error handling

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.

> 
> 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.

Thanks,
John