Re: [PATCH] scsi: ata: don't reset three times if device is offline for SAS host

[Tejun Heo <tj@kernel.org>]

Hello,

On Tue, Feb 13, 2018 at 09:44:53AM +0800, chenxiang (M) wrote:
> For those drivers using libsas,  i think they have the same issue.
> It takes about 1 minute to
> recover but actually device is gone, so this recover is useless for
> this scenario (when enter EH,
> all normal IOs are blocked actually, so it will cause normal IOs are
> blocked one more minute which
> user doesn't want to).

Right, it'd block other devices sharing the port.  Doesn't sas map
each ata device to its own port tho?

> Actually in sas_ata_hard_reset, there are two situations returned
> -ENODEV which represent device is gone:
> - LLDD directly returns -ENODEV through lldd_I_T_nexus_reset;
> - It sends SMP DISCOVER to check local phy in smp_ata_check_ready,
> and find it is gone;

So, if there are real consequences, we can definitely add a way to
short-circuit the recovery logic but let's do that by adding proper
signaling rathr than testing for driver type.

Thanks.

-- 
tejun