Re: [PATCH v5 2/2] scsi: libsas: terminate deferred commands on time out

[John Garry <john.g.garry@oracle.com>]

On 16/07/2026 09:38, Damien Le Moal wrote:
> If a command timeout occurs while we have a deferred non-NCQ command
> waiting to be issued, the SCSI EH task is not immediately woken up as the
> waiting deferred command is never issued nor completed, thus leaving this
> command to always be counted as "busy" for the SCSI host. This results in
> the test "shost->host_failed != scsi_host_busy(shost))" in the function
> scsi_error_handler() to always be true, keeping the EH task sleeping.
> Eventually, when the deferred command also times out, the SCSI EH task
> is woken up and the timeout processing occurs.
> 
> Avoid this unnecessary additional SCSI EH trigger wait time with the same
> method as implemented in libata-scsi, using the eh_timed_out SCSI host
> template operation. The function sas_eh_timed_out() implements this
> operation and executes the function ata_scsi_retry_deferred_qc()
> for SATA devices.
> 
> Co-developed-by: Igor Pylypiv<ipylypiv@google.com>
> Signed-off-by: Igor Pylypiv<ipylypiv@google.com>
> Fixes: 0ea84089dbf6 ("ata: libata-scsi: avoid Non-NCQ command starvation")
> Cc:stable@vger.kernel.org
> Signed-off-by: Damien Le Moal<dlemoal@kernel.org>

Reviewed-by: John Garry <john.g.garry@oracle.com>