Re: eh_abort_handler and calling scsi_done

[Brian King <brking@linux.vnet.ibm.com>]

Your assessment sounds correct to me. The other caveat to note is that
if for some reason in your eh_abort_handler you don't think the command
is still outstanding, you should return SUCCESS for this as well.

-Brian

Christof Schmitt wrote:
> I am investigating what is required from a LLD when SCSI commands time
> out and the SCSI EH calls the eh_abort_handler. The documentation in
> scsi_eh.txt states:
> 
>     <<scsi_eh_abort_cmds>>
> 
> 	This action is taken for each timed out command.
> 	hostt->eh_abort_handler() is invoked for each scmd.  The
> 	handler returns SUCCESS if it has succeeded to make LLDD and
> 	all related hardware forget about the scmd.
> 
> From this and from looking at the code, i would conclude:
> 
> 1) If the LLD returns FAILED from the eh_abort_handler, then the
>    command is still allowed to be active in the LLD and the LLD can
>    call scsi_done any time later (probably latest when the
>    eh_host_reset_handler flushes everything that is still pending).
> 
> 2) While the abort is pending, but before returning SUCCESS from
>    eh_abort_handler, the LLD can still call scsi_done for the SCSI
>    command to be aborted (the SCSI command might be returned with a
>    status "aborted" if the abort succeeds, or "good" if it was
>    completed just before the abort reached the storage system).
> 
> Is this correct? Are there any more limitations a SCSI LLD has to be
> aware of?
> 
> --
> Christof Schmitt
> --
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-- 
Brian King
Linux on Power Virtualization
IBM Linux Technology Center