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 <hawkxiang.cpp@xxxxxxxxx>
> ---
> V1 -> V2: Fix build variable 'sc' is uninitialized warning(Reported-by: kernel test robot <lkp@xxxxxxxxx>).
> ---
> 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.
