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Subject: Re: [PATCH] scsi: libsas: set tf to normal in
 sas_ata_device_link_abort()
To:     Xingui Yang <yangxingui@huawei.com>, <jejb@linux.ibm.com>,
        <martin.petersen@oracle.com>, <john.g.garry@oracle.com>
CC:     <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linuxarm@huawei.com>, <prime.zeng@hisilicon.com>,
        <kangfenglong@huawei.com>
References: <20230407035618.25123-1-yangxingui@huawei.com>
From:   Jason Yan <yanaijie@huawei.com>
Message-ID: <d00b38ce-99a8-208b-cdad-714bb3dbf60b@huawei.com>
Date:   Fri, 14 Apr 2023 15:36:47 +0800
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On 2023/4/7 11:56, Xingui Yang wrote:
> If the disk returns UNC for more than five times within a short period, the
> number of retry times for other I/Os may reach scmd->allowed, and the
> default error "Illegal Request" is returned for other I/Os, as follows:
> 
> [  273.801770] hisi_sas_v3_hw 0000:b4:02.0: erroneous completion disk err dev id=2 sas_addr=0x5000000000000605 CQ hdr: 0x400903 0x20103 0x0 0x80470000
> [  273.875286] sas: Enter sas_scsi_recover_host busy: 30 failed: 30
> [  273.879895] sas: trying to find task 0x00000000d9cfc893
> [  273.879896] sas: sas_scsi_find_task: aborting task 0x00000000d9cfc893
> [  273.880054] sas: sas_scsi_find_task: task 0x00000000d9cfc893 is done
> [  273.880055] sas: sas_eh_handle_sas_errors: task 0x00000000d9cfc893 is done
> [  273.880236] ata6.00: failed command: READ FPDMA QUEUED
> [  273.880238] ata6.00: cmd 60/08:00:59:27:00/00:00:00:00:00/40 tag 22 ncq dma 4096 in
>                          res 41/04:00:20:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
> [  273.880239] ata6.00: status: { DRDY ERR }
> [  273.880240] ata6.00: error: { ABRT }
> [  273.880241] ata6.00: failed command: READ FPDMA QUEUED
> [  273.880243] ata6.00: cmd 60/90:00:d1:26:00/00:00:00:00:00/40 tag 23 ncq dma 73728 in
>                          res 41/40:90:10:27:00/00:00:00:00:00/00 Emask 0x409 (media error) <F>
> [  273.880245] ata6.00: status: { DRDY ERR }
> [  273.880246] ata6.00: error: { UNC }
> [  273.880247] ata6.00: failed command: READ FPDMA QUEUED
> [  273.880249] ata6.00: cmd 60/08:00:19:27:00/00:00:00:00:00/40 tag 24 ncq dma 4096 in
>                          res 41/04:00:20:00:00/00:00:00:00:00/00 Emask 0x1 (device error)
> [  273.880250] ata6.00: status: { DRDY ERR }
> [  273.880251] ata6.00: error: { ABRT }
> [  274.199477] scmd->retries: 3, scmd->allowed: 5
> [  274.199478] scmd->retries: 3, scmd->allowed: 5
> [  274.199479] scmd->retries: 3, scmd->allowed: 5
> [  274.199481] scmd->retries: 3, scmd->allowed: 5
> [  274.199482] scmd->retries: 3, scmd->allowed: 5
> [  274.199483] scmd->retries: 2, scmd->allowed: 5
> [  274.199484] scmd->retries: 3, scmd->allowed: 5
> [  274.199485] scmd->retries: 3, scmd->allowed: 5
> [  274.199486] scmd->retries: 5, scmd->allowed: 5
> [  274.199487] scmd->retries: 2, scmd->allowed: 5
> [  274.199488] scmd->retries: 2, scmd->allowed: 5
> [  274.199524] sd 6:0:1:0: [sdb] tag#258 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
> [  274.199527] sd 6:0:1:0: [sdb] tag#258 Sense Key : Illegal Request [current]
> [  274.199530] sd 6:0:1:0: [sdb] tag#258 Add. Sense: Unaligned write command
> [  274.199532] sd 6:0:1:0: [sdb] tag#258 CDB: Read(10) 28 00 00 00 27 59 00 00 08 00
> [  274.199535] print_req_error: I/O error, dev sdb, sector 10073
> [  274.199573] sd 6:0:1:0: [sdb] tag#259 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
> [  274.199574] sd 6:0:1:0: [sdb] tag#259 Sense Key : Medium Error [current]
> [  274.199576] sd 6:0:1:0: [sdb] tag#259 Add. Sense: Unrecovered read error - auto reallocate failed
> [  274.199578] sd 6:0:1:0: [sdb] tag#259 CDB: Read(10) 28 00 00 00 26 d1 00 00 90 00
> [  274.199579] print_req_error: I/O error, dev sdb, sector 10000
> [  274.199608] ata6: EH complete
> [  274.199615] sas: --- Exit sas_scsi_recover_host: busy: 0 failed: 30 tries: 1
> 
> As mentioned in ata_eh_qc_retry(), if qc->err_mask is zero then increment
> scmd->allowed. So set tf to normal may be better.

Hi Xingui,

If we increase scmd->allowed every time, and the device returns UNC for 
too many times, will the other IO pending for too long and cause 
hungtask? And also the runtime check in scsi_cmd_runtime_exceeced() will 
not trigger since cmd->allowed is extended.

Thanks,
Jason

> 
> Signed-off-by: Xingui Yang <yangxingui@huawei.com>
> ---
>   drivers/scsi/libsas/sas_ata.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
> index 77714a495cbb..f5047e8dcb59 100644
> --- a/drivers/scsi/libsas/sas_ata.c
> +++ b/drivers/scsi/libsas/sas_ata.c
> @@ -949,8 +949,8 @@ void sas_ata_device_link_abort(struct domain_device *device, bool force_reset)
>   	unsigned long flags;
>   
>   	spin_lock_irqsave(ap->lock, flags);
> -	device->sata_dev.fis[2] = ATA_ERR | ATA_DRDY; /* tf status */
> -	device->sata_dev.fis[3] = ATA_ABORTED; /* tf error */
> +	device->sata_dev.fis[2] = ATA_DRDY; /* tf status */
> +	device->sata_dev.fis[3] = 0;        /* tf error */
>   
>   	link->eh_info.err_mask |= AC_ERR_DEV;
>   	if (force_reset)
>