target: Fix delayed Task Aborted Status (TAS) handling bug

This patch fixes a bug in delayed Task Aborted Status (TAS) handling,
where transport_send_task_abort() was not returning for the case
when the se_tfo->write_pending() callback indicated that last fabric
specific WRITE PDU had not yet been received.

It also adds an explicit cmd->scsi_status = SAM_STAT_TASK_ABORTED
assignment within transport_check_aborted_status() to avoid the case
where se_tfo->queue_status() is called when the SAM_STAT_TASK_ABORTED
assignment + ->queue_status() in transport_send_task_abort() does not
occur once SCF_SENT_DELAYED_TAS has been set.

Cc: <stable@vger.kernel.org> #3.2+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_transport.c

@@ -2682,6 +2682,7 @@ int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
 		 cmd->t_task_cdb[0], cmd->se_tfo->get_task_tag(cmd));
 
 	cmd->se_cmd_flags |= SCF_SENT_DELAYED_TAS;
+	cmd->scsi_status = SAM_STAT_TASK_ABORTED;
 	trace_target_cmd_complete(cmd);
 	cmd->se_tfo->queue_status(cmd);
 
@@ -2710,6 +2711,7 @@ void transport_send_task_abort(struct se_cmd *cmd)
 		if (cmd->se_tfo->write_pending_status(cmd) != 0) {
 			cmd->transport_state |= CMD_T_ABORTED;
 			smp_mb__after_atomic_inc();
+			return;
 		}
 	}
 	cmd->scsi_status = SAM_STAT_TASK_ABORTED;