--- zzzz-none-000/linux-3.10.107/drivers/s390/cio/css.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/s390/cio/css.c	2021-02-04 17:41:59.000000000 +0000
@@ -44,7 +44,6 @@
 	int ret;
 
 	init_subchannel_id(&schid);
-	ret = -ENODEV;
 	do {
 		do {
 			ret = fn(schid, data);
@@ -69,7 +68,8 @@
 	struct cb_data *cb = data;
 	int rc = 0;
 
-	idset_sch_del(cb->set, sch->schid);
+	if (cb->set)
+		idset_sch_del(cb->set, sch->schid);
 	if (cb->fn_known_sch)
 		rc = cb->fn_known_sch(sch, cb->data);
 	return rc;
@@ -115,6 +115,13 @@
 	cb.fn_known_sch = fn_known;
 	cb.fn_unknown_sch = fn_unknown;
 
+	if (fn_known && !fn_unknown) {
+		/* Skip idset allocation in case of known-only loop. */
+		cb.set = NULL;
+		return bus_for_each_dev(&css_bus_type, NULL, &cb,
+					call_fn_known_sch);
+	}
+
 	cb.set = idset_sch_new();
 	if (!cb.set)
 		/* fall back to brute force scanning in case of oom */
@@ -546,11 +553,16 @@
 		case -ENOMEM:
 		case -EIO:
 			/* These should abort looping */
+			spin_lock_irq(&slow_subchannel_lock);
 			idset_sch_del_subseq(slow_subchannel_set, schid);
+			spin_unlock_irq(&slow_subchannel_lock);
 			break;
 		default:
 			rc = 0;
 		}
+		/* Allow scheduling here since the containing loop might
+		 * take a while.  */
+		cond_resched();
 	}
 	return rc;
 }
@@ -570,7 +582,7 @@
 	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 }
 
-static DECLARE_WORK(slow_path_work, css_slow_path_func);
+static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 struct workqueue_struct *cio_work_q;
 
 void css_schedule_eval(struct subchannel_id schid)
@@ -580,7 +592,7 @@
 	spin_lock_irqsave(&slow_subchannel_lock, flags);
 	idset_sch_add(slow_subchannel_set, schid);
 	atomic_set(&css_eval_scheduled, 1);
-	queue_work(cio_work_q, &slow_path_work);
+	queue_delayed_work(cio_work_q, &slow_path_work, 0);
 	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 }
 
@@ -591,7 +603,7 @@
 	spin_lock_irqsave(&slow_subchannel_lock, flags);
 	idset_fill(slow_subchannel_set);
 	atomic_set(&css_eval_scheduled, 1);
-	queue_work(cio_work_q, &slow_path_work);
+	queue_delayed_work(cio_work_q, &slow_path_work, 0);
 	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 }
 
@@ -604,7 +616,7 @@
 	return 0;
 }
 
-static void css_schedule_eval_all_unreg(void)
+void css_schedule_eval_all_unreg(unsigned long delay)
 {
 	unsigned long flags;
 	struct idset *unreg_set;
@@ -622,7 +634,7 @@
 	spin_lock_irqsave(&slow_subchannel_lock, flags);
 	idset_add_set(slow_subchannel_set, unreg_set);
 	atomic_set(&css_eval_scheduled, 1);
-	queue_work(cio_work_q, &slow_path_work);
+	queue_delayed_work(cio_work_q, &slow_path_work, delay);
 	spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 	idset_free(unreg_set);
 }
@@ -635,7 +647,8 @@
 /* Schedule reprobing of all unregistered subchannels. */
 void css_schedule_reprobe(void)
 {
-	css_schedule_eval_all_unreg();
+	/* Schedule with a delay to allow merging of subsequent calls. */
+	css_schedule_eval_all_unreg(1 * HZ);
 }
 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 
@@ -689,17 +702,12 @@
 		css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 		css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 	} else {
-#ifdef CONFIG_SMP
 		css->global_pgid.pgid_high.cpu_addr = stap();
-#else
-		css->global_pgid.pgid_high.cpu_addr = 0;
-#endif
 	}
 	get_cpu_id(&cpu_id);
 	css->global_pgid.cpu_id = cpu_id.ident;
 	css->global_pgid.cpu_model = cpu_id.machine;
 	css->global_pgid.tod_high = tod_high;
-
 }
 
 static void
@@ -740,7 +748,7 @@
 	int ret;
 	unsigned long val;
 
-	ret = strict_strtoul(buf, 16, &val);
+	ret = kstrtoul(buf, 16, &val);
 	if (ret)
 		return ret;
 	mutex_lock(&css->mutex);
@@ -1075,6 +1083,7 @@
 		if (chp)
 			chp_update_desc(chp);
 	}
+	cmf_reactivate();
 }
 
 #ifdef CONFIG_PROC_FS