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Message-ID: <60ace19e-d029-f14d-9aac-d5cef83b5b64@huawei.com>
Date: Mon, 19 Dec 2022 23:28:47 +0800
From: Jason Yan <yanaijie@...wei.com>
To: John Garry <john.g.garry@...cle.com>,
Xingui Yang <yangxingui@...wei.com>, <jejb@...ux.ibm.com>,
<martin.petersen@...cle.com>, <damien.lemoal@...nsource.wdc.com>,
<linux-ide@...r.kernel.org>, <hare@...e.com>, <hch@....de>
CC: <linux-scsi@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linuxarm@...wei.com>, <prime.zeng@...ilicon.com>,
<kangfenglong@...wei.com>
Subject: Re: [PATCH V2] scsi: libsas: Directly kick-off EH when ATA device
fell off
On 2022/12/19 17:23, John Garry wrote:
> On 16/12/2022 10:03, Xingui Yang wrote:
>> If the ATA device fell off, call sas_ata_device_link_abort() directly and
>> mark all outstanding QCs as failed and kick-off EH Immediately. This
>> avoids
>> having to wait for block layer timeouts.
>>
>> Signed-off-by: Xingui Yang <yangxingui@...wei.com>
>> ---
>> Changes to v1:
>> - Use dev_is_sata() to check ATA device type
>> drivers/scsi/libsas/sas_discover.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/scsi/libsas/sas_discover.c
>> b/drivers/scsi/libsas/sas_discover.c
>> index d5bc1314c341..a12b65eb4a2a 100644
>> --- a/drivers/scsi/libsas/sas_discover.c
>> +++ b/drivers/scsi/libsas/sas_discover.c
>> @@ -362,6 +362,9 @@ static void sas_destruct_ports(struct asd_sas_port
>> *port)
>> void sas_unregister_dev(struct asd_sas_port *port, struct
>> domain_device *dev)
>> {
>> + if (test_bit(SAS_DEV_GONE, &dev->state) && dev_is_sata(dev))
>> + sas_ata_device_link_abort(dev, false);
>
> Firstly, I think that there is a bug in sas_ata_device_link_abort() ->
> ata_link_abort() code in that the host lock in not grabbed, as the
> comment in ata_port_abort() mentions. Having said that, libsas had
> already some dodgy host locking usage - specifically dropping the lock
> for the queuing path (that's something else to be fixed up ... I think
Taking big locks in queuing path is not a good idea. This will bring
down performance.
> that is due to queue command CB calling task_done() in some cases), but
> I still think that sas_ata_device_link_abort() should be fixed (to grab
> the host lock).
For sas_ata_device_link_abort(), it should grab ap->lock.
Thanks,
Jason
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