PCI: shpchp: Handle push button event asynchronously

Use non-ordered workqueue for attention button events.

Attention button events on each slot can be handled asynchronously. So
we should use non-ordered workqueue. This patch also removes ordered
workqueue in shpchp as a result.

486b10b9f4 ("PCI: pciehp: Handle push button event asynchronously") made
the same change to pciehp.  I split this out from a patch by Yijing Wang
<wangyijing@huawei.com> so we fix one thing at a time and to make the
shpchp history correspond more closely with the pciehp history.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>

drivers/pci/hotplug/shpchp.h

@@ -47,7 +47,6 @@ extern bool shpchp_poll_mode;
 extern int shpchp_poll_time;
 extern bool shpchp_debug;
 extern struct workqueue_struct *shpchp_wq;
-extern struct workqueue_struct *shpchp_ordered_wq;
 
 #define dbg(format, arg...)						\
 do {									\

drivers/pci/hotplug/shpchp_core.c

@@ -40,7 +40,6 @@ bool shpchp_debug;
 bool shpchp_poll_mode;
 int shpchp_poll_time;
 struct workqueue_struct *shpchp_wq;
-struct workqueue_struct *shpchp_ordered_wq;
 
 #define DRIVER_VERSION	"0.4"
 #define DRIVER_AUTHOR	"Dan Zink <dan.zink@compaq.com>, Greg Kroah-Hartman <greg@kroah.com>, Dely Sy <dely.l.sy@intel.com>"
@@ -181,7 +180,6 @@ void cleanup_slots(struct controller *ctrl)
 		list_del(&slot->slot_list);
 		cancel_delayed_work(&slot->work);
 		flush_workqueue(shpchp_wq);
-		flush_workqueue(shpchp_ordered_wq);
 		pci_hp_deregister(slot->hotplug_slot);
 	}
 }
@@ -370,17 +368,10 @@ static int __init shpcd_init(void)
 	if (!shpchp_wq)
 		return -ENOMEM;
 
-	shpchp_ordered_wq = alloc_ordered_workqueue("shpchp_ordered", 0);
-	if (!shpchp_ordered_wq) {
-		destroy_workqueue(shpchp_wq);
-		return -ENOMEM;
-	}
-
 	retval = pci_register_driver(&shpc_driver);
 	dbg("%s: pci_register_driver = %d\n", __func__, retval);
 	info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
 	if (retval) {
-		destroy_workqueue(shpchp_ordered_wq);
 		destroy_workqueue(shpchp_wq);
 	}
 	return retval;
@@ -390,7 +381,6 @@ static void __exit shpcd_cleanup(void)
 {
 	dbg("unload_shpchpd()\n");
 	pci_unregister_driver(&shpc_driver);
-	destroy_workqueue(shpchp_ordered_wq);
 	destroy_workqueue(shpchp_wq);
 	info(DRIVER_DESC " version: " DRIVER_VERSION " unloaded\n");
 }

drivers/pci/hotplug/shpchp_ctrl.c

@@ -453,7 +453,7 @@ void shpchp_queue_pushbutton_work(struct work_struct *work)
 		kfree(info);
 		goto out;
 	}
-	queue_work(shpchp_ordered_wq, &info->work);
+	queue_work(shpchp_wq, &info->work);
  out:
 	mutex_unlock(&p_slot->lock);
 }