On 10/14/24 12:36 AM, Xiang Zhang wrote:
> Initiator need to recover session and reconnect to target, after calling 
> stop_conn. And target will rebuild new session info, and mark 
> ASC_POWERON_RESET ua sense for scsi devices belong to the target(device 
> reset). After recovery, first scsi command(scmd) request to target will get 
> ASC_POWERON_RESET(ua sense) + SAM_STAT_CHECK_CONDITION(status) in response.
> For command's response coming, according to scsi function calling: "scsi_done 
> --> scsi_complete --> scsi_decide_disposition --> scsi_check_sense", if 
> expecting_cc_ua = 0, scmd response with ASC_POWERON_RESET(ua sense) will make 
> scsi_complete ignore "cmd->retries <= cmd->allowed", fail directly. It will 
> cause SCSI return io_error to upper layer without retry.
> If we set expecting_cc_ua=1 in fail_scsi_tasks, scsi_complete will retry scmd 
> which is response with ASC_POWERON_RESET. The scmd second request to target 
> can successful, because target will clear ASC_POWERON_RESET in device pending 
> ua_sense_list after first scmd request.
> 
> Signed-off-by: Xiang Zhang <[email protected]>
> ---
> V1 -> V2: Fix build variable 'sc' is uninitialized warning(Reported-by: 
> kernel test robot <[email protected]>).
> ---
>  drivers/scsi/libiscsi.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
> index 0fda8905eabd..f6bfe0c4f8a4 100644
> --- a/drivers/scsi/libiscsi.c
> +++ b/drivers/scsi/libiscsi.c
> @@ -621,6 +621,7 @@ static void __fail_scsi_task(struct iscsi_task *task, int 
> err)
>       if (cleanup_queued_task(task))
>               return;
>  
> +     sc = task->sc;
>       if (task->state == ISCSI_TASK_PENDING) {
>               /*
>                * cmd never made it to the xmit thread, so we should not count
> @@ -629,12 +630,12 @@ static void __fail_scsi_task(struct iscsi_task *task, 
> int err)
>               conn->session->queued_cmdsn--;
>               /* it was never sent so just complete like normal */
>               state = ISCSI_TASK_COMPLETED;
> -     } else if (err == DID_TRANSPORT_DISRUPTED)
> +     } else if (err == DID_TRANSPORT_DISRUPTED) {
>               state = ISCSI_TASK_ABRT_SESS_RECOV;
> -     else
> +             sc->device->expecting_cc_ua = 1;
> +     } else
>               state = ISCSI_TASK_ABRT_TMF;
>  
> -     sc = task->sc;
>       sc->result = err << 16;
>       scsi_set_resid(sc, scsi_bufflen(sc));
>       iscsi_complete_task(task, state);


This should be fixed in a common way like I mentioned in the other thread.

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