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);
--
2.44.0
