target: Fix Task Aborted Status (TAS) handling

This patch addresses three of long standing issues wrt to Task
Aborted Status (TAS) handling.

The first is the incorrect assumption in core_tmr_handle_tas_abort()
that TASK_ABORTED status is sent for the task referenced by TMR
ABORT_TASK, and sending TASK_ABORTED status for TMR LUN_RESET on
the same nexus the LUN_RESET was received.

The second is to ensure the lun reference count is dropped within
transport_cmd_finish_abort() by calling transport_lun_remove_cmd()
before invoking transport_cmd_check_stop_to_fabric().

The last is to fix the delayed TAS handling to allow outstanding
WRITEs to complete before sending the TASK_ABORTED status. This
includes changing transport_check_aborted_status() to avoid
processing when SCF_SEND_DELAYED_TAS has not be set, and updating
transport_send_task_abort() to drop the SCF_SENT_DELAYED_TAS
check.

Signed-off-by: Alex Leung <amleung21@yahoo.com>
Cc: Alex Leung <amleung21@yahoo.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c
index 70c638f..3f0338f 100644
--- a/drivers/target/target_core_tmr.c
+++ b/drivers/target/target_core_tmr.c
@@ -87,14 +87,17 @@
 	struct se_cmd *cmd,
 	int tas)
 {
+	bool remove = true;
 	/*
 	 * TASK ABORTED status (TAS) bit support
 	*/
 	if ((tmr_nacl &&
-	     (tmr_nacl == cmd->se_sess->se_node_acl)) || tas)
+	     (tmr_nacl != cmd->se_sess->se_node_acl)) && tas) {
+		remove = false;
 		transport_send_task_abort(cmd);
+	}
 
-	transport_cmd_finish_abort(cmd, 0);
+	transport_cmd_finish_abort(cmd, remove);
 }
 
 static int target_check_cdb_and_preempt(struct list_head *list,
@@ -150,18 +153,9 @@
 
 		cancel_work_sync(&se_cmd->work);
 		transport_wait_for_tasks(se_cmd);
-		/*
-		 * Now send SAM_STAT_TASK_ABORTED status for the referenced
-		 * se_cmd descriptor..
-		 */
-		transport_send_task_abort(se_cmd);
-		/*
-		 * Also deal with possible extra acknowledge reference..
-		 */
-		if (se_cmd->se_cmd_flags & SCF_ACK_KREF)
-			target_put_sess_cmd(se_sess, se_cmd);
 
 		target_put_sess_cmd(se_sess, se_cmd);
+		transport_cmd_finish_abort(se_cmd, true);
 
 		printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 				" ref_tag: %d\n", ref_tag);