static int io_subchannel_sch_event()

in cio/device.c [1422:1542]

• 104 lines of code
• 27 McCabe index (conditional complexity)

static int io_subchannel_sch_event(struct subchannel *sch, int process)
{
	unsigned long flags;
	struct ccw_device *cdev;
	struct ccw_dev_id dev_id;
	enum io_sch_action action;
	int rc = -EAGAIN;

	spin_lock_irqsave(sch->lock, flags);
	if (!device_is_registered(&sch->dev))
		goto out_unlock;
	if (work_pending(&sch->todo_work))
		goto out_unlock;
	cdev = sch_get_cdev(sch);
	if (cdev && work_pending(&cdev->private->todo_work))
		goto out_unlock;
	action = sch_get_action(sch);
	CIO_MSG_EVENT(2, "event: sch 0.%x.%04x, process=%d, action=%d\n",
		      sch->schid.ssid, sch->schid.sch_no, process,
		      action);
	/* Perform immediate actions while holding the lock. */
	switch (action) {
	case IO_SCH_REPROBE:
		/* Trigger device recognition. */
		ccw_device_trigger_reprobe(cdev);
		rc = 0;
		goto out_unlock;
	case IO_SCH_VERIFY:
		/* Trigger path verification. */
		io_subchannel_verify(sch);
		rc = 0;
		goto out_unlock;
	case IO_SCH_DISC:
		ccw_device_set_disconnected(cdev);
		rc = 0;
		goto out_unlock;
	case IO_SCH_ORPH_UNREG:
	case IO_SCH_ORPH_ATTACH:
		ccw_device_set_disconnected(cdev);
		break;
	case IO_SCH_UNREG_ATTACH:
	case IO_SCH_UNREG:
		if (!cdev)
			break;
		if (cdev->private->state == DEV_STATE_SENSE_ID) {
			/*
			 * Note: delayed work triggered by this event
			 * and repeated calls to sch_event are synchronized
			 * by the above check for work_pending(cdev).
			 */
			dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
		} else
			ccw_device_set_notoper(cdev);
		break;
	case IO_SCH_NOP:
		rc = 0;
		goto out_unlock;
	default:
		break;
	}
	spin_unlock_irqrestore(sch->lock, flags);
	/* All other actions require process context. */
	if (!process)
		goto out;
	/* Handle attached ccw device. */
	switch (action) {
	case IO_SCH_ORPH_UNREG:
	case IO_SCH_ORPH_ATTACH:
		/* Move ccw device to orphanage. */
		rc = ccw_device_move_to_orph(cdev);
		if (rc)
			goto out;
		break;
	case IO_SCH_UNREG_ATTACH:
		spin_lock_irqsave(sch->lock, flags);
		sch_set_cdev(sch, NULL);
		spin_unlock_irqrestore(sch->lock, flags);
		/* Unregister ccw device. */
		ccw_device_unregister(cdev);
		break;
	default:
		break;
	}
	/* Handle subchannel. */
	switch (action) {
	case IO_SCH_ORPH_UNREG:
	case IO_SCH_UNREG:
		css_sch_device_unregister(sch);
		break;
	case IO_SCH_ORPH_ATTACH:
	case IO_SCH_UNREG_ATTACH:
	case IO_SCH_ATTACH:
		dev_id.ssid = sch->schid.ssid;
		dev_id.devno = sch->schib.pmcw.dev;
		cdev = get_ccwdev_by_dev_id(&dev_id);
		if (!cdev) {
			sch_create_and_recog_new_device(sch);
			break;
		}
		rc = ccw_device_move_to_sch(cdev, sch);
		if (rc) {
			/* Release reference from get_ccwdev_by_dev_id() */
			put_device(&cdev->dev);
			goto out;
		}
		spin_lock_irqsave(sch->lock, flags);
		ccw_device_trigger_reprobe(cdev);
		spin_unlock_irqrestore(sch->lock, flags);
		/* Release reference from get_ccwdev_by_dev_id() */
		put_device(&cdev->dev);
		break;
	default:
		break;
	}
	return 0;

out_unlock:
	spin_unlock_irqrestore(sch->lock, flags);
out:
	return rc;
}