Re: [PATCH] scsi_transport_fc: Make 'port_state' writeable

[Bart Van Assche <bvanassche@acm.org>]

On 03/15/13 14:28, Bryn M. Reeves wrote:
> On 03/15/2013 12:46 PM, Bart Van Assche wrote:
>> The SCSI EH keeps trying until all outstanding request have been
>> finished. Does lpfc_host_reset_handler() invoke scsi_done() for
>
> I don't think so (ends up calling lpfc_sli_cancel_iocbs() via
> lpfc_hba_down_post() after shutting down the mailbox) but I've not seen
> the EH escalate all the way to host reset in most of my testing -
> usually some time after reaching the bus reset remaining IOs timeout and
> the error bubbles up to device-mapper (all the cases I'm looking at are
> devices managed by a dm-multipath target).
>
> The problem is that getting to this stage can take a very long time -
> much longer than most cluster's node eviction timer for e.g. which is
> the source of much of the complaint about this behaviour.
>
>> outstanding requests ? If not, how about modifying
>> lpfc_host_reset_handler() such that it finishes all outstanding requests
>> if the remote port is not reachable ?
>
> I'm not sure how safe that is in this situation - James mentioned in the
> I_T nexus reset thread concerns about frames that could be delayed etc.
> in the fabric if the host unilaterally abandons IOs (not sure of the
> details for lpfc at this level).

How about using the value of scsi_cmnd.jiffies_at_alloc to finish only 
those SCSI commands in the host reset handler that exceeded a certain 
processing time ?

Bart.