scsi: libiscsi: Fix iscsi_prep_scsi_cmd_pdu() error handling

[ Upstream commit d28d48c ]

If iscsi_prep_scsi_cmd_pdu() fails we try to add it back to the cmdqueue,
but we leave it partially setup. We don't have functions that can undo the
pdu and init task setup. We only have cleanup_task which can clean up both
parts. So this has us just fail the cmd and go through the standard cleanup
routine and then have the SCSI midlayer retry it like is done when it fails
in the queuecommand path.

Link: https://lore.kernel.org/r/20210207044608.27585-2-michael.christie@oracle.com
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/scsi/libiscsi.c

@@ -1532,14 +1532,9 @@ static int iscsi_data_xmit(struct iscsi_conn *conn)
 		}
 		rc = iscsi_prep_scsi_cmd_pdu(conn->task);
 		if (rc) {
-			if (rc == -ENOMEM || rc == -EACCES) {
-				spin_lock_bh(&conn->taskqueuelock);
-				list_add_tail(&conn->task->running,
-					      &conn->cmdqueue);
-				conn->task = NULL;
-				spin_unlock_bh(&conn->taskqueuelock);
-				goto done;
-			} else
+			if (rc == -ENOMEM || rc == -EACCES)
+				fail_scsi_task(conn->task, DID_IMM_RETRY);
+			else
 				fail_scsi_task(conn->task, DID_ABORT);
 			spin_lock_bh(&conn->taskqueuelock);
 			continue;