[S390] cio: introduce css_settle

Introduce the css_driver callback settle which can be implemented
by a subchannel driver to wait for the subchannel type specific
asynchronous work to finish.
In channel_subsystem_init_sync we call that for each subchannel
driver.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/device.c b/drivers/s390/cio/device.c
index 4093adc..f780bdd 100644
--- a/drivers/s390/cio/device.c
+++ b/drivers/s390/cio/device.c
@@ -131,6 +131,10 @@
 static int io_subchannel_sch_event(struct subchannel *, int);
 static int io_subchannel_chp_event(struct subchannel *, struct chp_link *,
 				   int);
+static void recovery_func(unsigned long data);
+struct workqueue_struct *ccw_device_work;
+wait_queue_head_t ccw_device_init_wq;
+atomic_t ccw_device_init_count;
 
 static struct css_device_id io_subchannel_ids[] = {
 	{ .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
@@ -151,6 +155,13 @@
 	return 0;
 }
 
+static void io_subchannel_settle(void)
+{
+	wait_event(ccw_device_init_wq,
+		   atomic_read(&ccw_device_init_count) == 0);
+	flush_workqueue(ccw_device_work);
+}
+
 static struct css_driver io_subchannel_driver = {
 	.owner = THIS_MODULE,
 	.subchannel_type = io_subchannel_ids,
@@ -162,14 +173,9 @@
 	.remove = io_subchannel_remove,
 	.shutdown = io_subchannel_shutdown,
 	.prepare = io_subchannel_prepare,
+	.settle = io_subchannel_settle,
 };
 
-struct workqueue_struct *ccw_device_work;
-wait_queue_head_t ccw_device_init_wq;
-atomic_t ccw_device_init_count;
-
-static void recovery_func(unsigned long data);
-
 int __init io_subchannel_init(void)
 {
 	int ret;