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Subject: Re: [PATCH V2] scsi: libsas: Directly kick-off EH when ATA device
 fell off
To:     John Garry <john.g.garry@oracle.com>,
        yangxingui <yangxingui@huawei.com>, <jejb@linux.ibm.com>,
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From:   Jason Yan <yanaijie@huawei.com>
Message-ID: <0ec55896-a690-9aca-a85a-4e6584e27967@huawei.com>
Date:   Wed, 21 Dec 2022 18:29:04 +0800
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On 2022/12/21 17:40, John Garry wrote:
> On 20/12/2022 09:49, Jason Yan wrote:
>>
>> Itering tagset in libsas is odd.
> 
> Itering with block layer APIs is just a method to deal with each active 
> IO. However, libsas should not be aborting IO directly. It may provide 
> helper routines, but the LLDD should be dealing with aborting IO.
> 
>  >
>  > The question is, shall we implement the aborting from the driver side,
>  > such as what sas_ata_device_link_abort() do. Or shall we implement the
>  > aborting from the upper side(scsi middle layer or block layer), such as
>  > trigger block layer time out handler immediately after we found device
>  > is gone?
> 
> As mentioned, aborting each IO should be the job of the LLDD. However, 
> just making the IO timeout will lead to EH kicking in earlier, and EH 
> will do usual per-IO handling in sas_eh_handle_sas_errors() that would 
> happen when the IO timesout normally - so what are we really gaining 
> here? Just EH kicks in earlier. But we still have the problem of all 
> other per-host IO being blocked while EH is active.

This is not the same issue as I replied yesterday.
https://lkml.org/lkml/2022/12/19/1034

Thanks,
Jason