mei: stop the stall timer worker if not needed

The stall timer worker checks periodically if there is a stalled i/o
transaction. The issue with the current implementation is that the timer
is ticking also when there is no pending i/o transaction.
This patch provides a simple change that prevents rescheduling
of the delayed work when there is no pending i/o.

Cc: Andy Lutomirski <[e-mail]>
Signed-off-by: Alexander Usyskin <[e-mail]>
Signed-off-by: Tomas Winkler <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/mei/amthif.c

···
 	case MEI_FOP_WRITE:
 		if (!cb->status) {
 			dev->iamthif_stall_timer = MEI_IAMTHIF_STALL_TIMER;
+			mei_schedule_stall_timer(dev);
 			mei_io_cb_free(cb);
 			return;
 		}

drivers/misc/mei/client.c

···
 
 	list_move_tail(&cb->list, &dev->ctrl_rd_list.list);
 	cl->timer_count = MEI_CONNECT_TIMEOUT;
+	mei_schedule_stall_timer(dev);
 
 	return 0;
 }
···
 
 	list_move_tail(&cb->list, &dev->ctrl_rd_list.list);
 	cl->timer_count = MEI_CONNECT_TIMEOUT;
+	mei_schedule_stall_timer(dev);
 	return 0;
 }
 

drivers/misc/mei/hbm.c

···
 
 	dev->hbm_state = MEI_HBM_STARTING;
 	dev->init_clients_timer = MEI_CLIENTS_INIT_TIMEOUT;
+	mei_schedule_stall_timer(dev);
 	return 0;
 }
 
···
 	}
 	dev->hbm_state = MEI_HBM_ENUM_CLIENTS;
 	dev->init_clients_timer = MEI_CLIENTS_INIT_TIMEOUT;
+	mei_schedule_stall_timer(dev);
 	return 0;
 }
 
···
 	}
 
 	dev->init_clients_timer = MEI_CLIENTS_INIT_TIMEOUT;
+	mei_schedule_stall_timer(dev);
 
 	return 0;
 }

drivers/misc/mei/init.c

···
 	cancel_work_sync(&dev->reset_work);
 	cancel_work_sync(&dev->bus_rescan_work);
 
-	cancel_delayed_work(&dev->timer_work);
+	cancel_delayed_work_sync(&dev->timer_work);
 }
 EXPORT_SYMBOL_GPL(mei_cancel_work);
 

drivers/misc/mei/interrupt.c

···
 	mei_reset(dev);
 }
 
+#define MEI_STALL_TIMER_FREQ (2 * HZ)
+/**
+ * mei_schedule_stall_timer - re-arm stall_timer work
+ *
+ * Schedule stall timer
+ *
+ * @dev: the device structure
+ */
+void mei_schedule_stall_timer(struct mei_device *dev)
+{
+	schedule_delayed_work(&dev->timer_work, MEI_STALL_TIMER_FREQ);
+}
+
 /**
  * mei_timer - timer function.
  *
···
 void mei_timer(struct work_struct *work)
 {
 	struct mei_cl *cl;
-
 	struct mei_device *dev = container_of(work,
 					struct mei_device, timer_work.work);
-
+	bool reschedule_timer = false;
 
 	mutex_lock(&dev->device_lock);
 
···
 				mei_reset(dev);
 				goto out;
 			}
+			reschedule_timer = true;
 		}
 	}
 
···
 				mei_connect_timeout(cl);
 				goto out;
 			}
+			reschedule_timer = true;
 		}
 	}
 
···
 			mei_reset(dev);
 
 			mei_amthif_run_next_cmd(dev);
+			goto out;
 		}
+		reschedule_timer = true;
 	}
 
 out:
-	if (dev->dev_state != MEI_DEV_DISABLED)
-		schedule_delayed_work(&dev->timer_work, 2 * HZ);
+	if (dev->dev_state != MEI_DEV_DISABLED && reschedule_timer)
+		mei_schedule_stall_timer(dev);
+
 	mutex_unlock(&dev->device_lock);
 }

drivers/misc/mei/mei_dev.h

···
  */
 
 void mei_timer(struct work_struct *work);
+void mei_schedule_stall_timer(struct mei_device *dev);
 int mei_irq_read_handler(struct mei_device *dev,
 		struct mei_cl_cb *cmpl_list, s32 *slots);
 

drivers/misc/mei/pci-me.c

···
 
 	pci_set_drvdata(pdev, dev);
 
-	schedule_delayed_work(&dev->timer_work, HZ);
-
 	/*
 	* For not wake-able HW runtime pm framework
 	* can't be used on pci device level.