Messages in this thread |  | | Date | Mon, 19 Dec 2022 14:53:32 +0000 | Subject | Re: [PATCH V2] scsi: libsas: Directly kick-off EH when ATA device fell off | From | John Garry <> |
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On 19/12/2022 12:59, yangxingui wrote: >> 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 >> 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). > ok, I agree with you very much for this, I had doubts about whether we > needed to grab lock before.
ok, I hope that you can fix this up separately.
>> >> Secondly, this just seems like a half solution to the age-old problem >> - that is, EH eventually kicking in only after 30 seconds when a disk >> is removed with active IO. I say half solution as SAS disks still have >> this issue for libsas. Can we instead push to try to solve both of >> them now? > > Jason said you must have such an opinion "a half solution". As libsas > does not have any interface to mark all outstanding commands as failed > for SAS disk currently and SAS disk support I/O resumable transmission > after intermittent disconnections
I don't know what you mean by "resumable transmission after intermittent disconnections".
> , so I want to optimize sata disk first. > If we want to achieve a complete solution, perhaps we need to define > such an interface in libsas and implement it by lldd. My current idea is > to call sas_abort_task() for all outstanding commands in lldd. I wonder > if you approve of this?
Are you sure you mean sas_abort_task()? That is for the LLDD to issue an abort TMF. I assume that you mean sas_task_abort(). If so, I am not too keen on the idea of libsas calling into the LLDD to inform of such an event. Note that maybe a tagset iter function could be used by libsas to abort each active IO, but I don't like libsas messing with such a thing; in addition, there may be some conflict between libsas aborting the IO and the IO completing with error in the LLDD.
Please note that I need to refresh my memory on this whole EH topic...
Thanks, John
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