Re: [PATCH] scsi: libsas: set tf to normal in sas_ata_device_link_abort()

[yangxingui <yangxingui@xxxxxxxxxx>]

On 2023/4/26 9:41, Jason Yan wrote:
> On 2023/4/17 16:18, yangxingui wrote:
> > Hi Jason
> >
> > On 2023/4/14 15:36, Jason Yan wrote:
> > > 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.
> > Thank you for your reply. In scenarios similar to UNC error, where a 
> > disk returns an error through D2H or SDB, no error is reported for 
> > other I/Os in the disk. In this case, AHCI will increase the number of 
> > retry times for other I/Os, and AHCI may face similar problems you 
> > say, but default failures may not be very good for users.
Hi Jason
> I think at least we cannot always retry unconditionally. Failure is 
> better than hung becuase users can deal with failures. They can retry 
> from the userspace. But if the process stuck in kernel, it is a disaster 
> for the userspace and they can do nothing. Is there a way to limit the 
> times of retry
During this period, the user will receive the I/O error of UNC all the 
time unless the user stops accessing the disk.

Thanks,
Xingui
> Thanks,
> Jason
>
> > In addition, for commands with pass through type, other I/Os are 
> > immediately returned with default errors and are not retried, but AHCI 
> > only report one single error I/O.
> >
> > Thanks,
> > Xingui
> >
> > > Thanks,
> > > Jason
> > >
> > > > Signed-off-by: Xingui Yang <yangxingui@xxxxxxxxxx>
> > > > ---
> > > >   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)
> > > .
> > .
> .