scsi: target: Add tmr_notify backend function

Target core is modified to call an optional backend callback function if a
TMR is received or commands are aborted implicitly after a PR command was
received.  The backend function takes as parameters the se_dev, the type of
the TMR, and the list of aborted commands.  If no commands were aborted, an
empty list is supplied.

Link: https://lore.kernel.org/r/20200726153510.13077-3-bstroesser@ts.fujitsu.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Bodo Stroesser <bstroesser@ts.fujitsu.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/target/target_core_tmr.c

@@ -116,6 +116,7 @@ void core_tmr_abort_task(
 	struct se_tmr_req *tmr,
 	struct se_session *se_sess)
 {
+	LIST_HEAD(aborted_list);
 	struct se_cmd *se_cmd, *next;
 	unsigned long flags;
 	bool rc;
@@ -144,7 +145,7 @@ void core_tmr_abort_task(
 		if (!rc)
 			continue;
 
-		list_del_init(&se_cmd->state_list);
+		list_move_tail(&se_cmd->state_list, &aborted_list);
 		se_cmd->state_active = false;
 
 		spin_unlock_irqrestore(&dev->execute_task_lock, flags);
@@ -157,6 +158,11 @@ void core_tmr_abort_task(
 			WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd) <
 					0);
 
+		if (dev->transport->tmr_notify)
+			dev->transport->tmr_notify(dev, TMR_ABORT_TASK,
+						   &aborted_list);
+
+		list_del_init(&se_cmd->state_list);
 		target_put_cmd_and_wait(se_cmd);
 
 		printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
@@ -167,6 +173,9 @@ void core_tmr_abort_task(
 	}
 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 
+	if (dev->transport->tmr_notify)
+		dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list);
+
 	printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 			tmr->ref_task_tag);
 	tmr->response = TMR_TASK_DOES_NOT_EXIST;
@@ -318,6 +327,11 @@ static void core_tmr_drain_state_list(
 	}
 	spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 
+	if (dev->transport->tmr_notify)
+		dev->transport->tmr_notify(dev, preempt_and_abort_list ?
+					   TMR_LUN_RESET_PRO : TMR_LUN_RESET,
+					   &drain_task_list);
+
 	while (!list_empty(&drain_task_list)) {
 		cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 		list_del_init(&cmd->state_list);

drivers/target/target_core_transport.c

@@ -2946,6 +2946,7 @@ static const char *target_tmf_name(enum tcm_tmreq_table tmf)
 	case TMR_LUN_RESET:		return "LUN_RESET";
 	case TMR_TARGET_WARM_RESET:	return "TARGET_WARM_RESET";
 	case TMR_TARGET_COLD_RESET:	return "TARGET_COLD_RESET";
+	case TMR_LUN_RESET_PRO:		return "LUN_RESET_PRO";
 	case TMR_UNKNOWN:		break;
 	}
 	return "(?)";

include/target/target_core_backend.h

@@ -40,6 +40,8 @@ struct target_backend_ops {
 	ssize_t (*show_configfs_dev_params)(struct se_device *, char *);
 
 	sense_reason_t (*parse_cdb)(struct se_cmd *cmd);
+	void (*tmr_notify)(struct se_device *se_dev, enum tcm_tmreq_table,
+			   struct list_head *aborted_cmds);
 	u32 (*get_device_type)(struct se_device *);
 	sector_t (*get_blocks)(struct se_device *);
 	sector_t (*get_alignment_offset_lbas)(struct se_device *);

include/target/target_core_base.h

@@ -207,6 +207,7 @@ enum tcm_tmreq_table {
 	TMR_LUN_RESET		= 5,
 	TMR_TARGET_WARM_RESET	= 6,
 	TMR_TARGET_COLD_RESET	= 7,
+	TMR_LUN_RESET_PRO	= 0x80,
 	TMR_UNKNOWN		= 0xff,
 };