1 files changed, 66 insertions, 13 deletions

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 7679aee6fa14..2769da54f2b9 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -18,6 +18,7 @@
 #include <linux/list.h>
 #include <linux/reboot.h>
 #include <linux/suspend.h>
+#include <linux/proc_fs.h>
 #include <asm/isc.h>
 #include <asm/crw.h>
 
@@ -232,7 +233,7 @@ void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
         if (!get_device(&sch->dev))
                 return;
         sch->todo = todo;
-        if (!queue_work(slow_path_wq, &sch->todo_work)) {
+        if (!queue_work(cio_work_q, &sch->todo_work)) {
                 /* Already queued, release workqueue ref. */
                 put_device(&sch->dev);
         }
@@ -543,7 +544,7 @@ static void css_slow_path_func(struct work_struct *unused)
 }
 
 static DECLARE_WORK(slow_path_work, css_slow_path_func);
-struct workqueue_struct *slow_path_wq;
+struct workqueue_struct *cio_work_q;
 
 void css_schedule_eval(struct subchannel_id schid)
 {
@@ -552,7 +553,7 @@ void css_schedule_eval(struct subchannel_id schid)
         spin_lock_irqsave(&slow_subchannel_lock, flags);
         idset_sch_add(slow_subchannel_set, schid);
         atomic_set(&css_eval_scheduled, 1);
-        queue_work(slow_path_wq, &slow_path_work);
+        queue_work(cio_work_q, &slow_path_work);
         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 }
 
@@ -563,7 +564,7 @@ void css_schedule_eval_all(void)
         spin_lock_irqsave(&slow_subchannel_lock, flags);
         idset_fill(slow_subchannel_set);
         atomic_set(&css_eval_scheduled, 1);
-        queue_work(slow_path_wq, &slow_path_work);
+        queue_work(cio_work_q, &slow_path_work);
         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 }
 
@@ -594,14 +595,14 @@ void css_schedule_eval_all_unreg(void)
         spin_lock_irqsave(&slow_subchannel_lock, flags);
         idset_add_set(slow_subchannel_set, unreg_set);
         atomic_set(&css_eval_scheduled, 1);
-        queue_work(slow_path_wq, &slow_path_work);
+        queue_work(cio_work_q, &slow_path_work);
         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
         idset_free(unreg_set);
 }
 
 void css_wait_for_slow_path(void)
 {
-        flush_workqueue(slow_path_wq);
+        flush_workqueue(cio_work_q);
 }
 
 /* Schedule reprobing of all unregistered subchannels. */
@@ -992,12 +993,21 @@ static int __init channel_subsystem_init(void)
         ret = css_bus_init();
         if (ret)
                 return ret;
-
+        cio_work_q = create_singlethread_workqueue("cio");
+        if (!cio_work_q) {
+                ret = -ENOMEM;
+                goto out_bus;
+        }
         ret = io_subchannel_init();
         if (ret)
-                css_bus_cleanup();
+                goto out_wq;
 
         return ret;
+out_wq:
+        destroy_workqueue(cio_work_q);
+out_bus:
+        css_bus_cleanup();
+        return ret;
 }
 subsys_initcall(channel_subsystem_init);
 
@@ -1006,10 +1016,25 @@ static int css_settle(struct device_driver *drv, void *unused)
         struct css_driver *cssdrv = to_cssdriver(drv);
 
         if (cssdrv->settle)
-                cssdrv->settle();
+                return cssdrv->settle();
         return 0;
 }
 
+int css_complete_work(void)
+{
+        int ret;
+
+        /* Wait for the evaluation of subchannels to finish. */
+        ret = wait_event_interruptible(css_eval_wq,
+                                       atomic_read(&css_eval_scheduled) == 0);
+        if (ret)
+                return -EINTR;
+        flush_workqueue(cio_work_q);
+        /* Wait for the subchannel type specific initialization to finish */
+        return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
+}
+
+
 /*
  * Wait for the initialization of devices to finish, to make sure we are
  * done with our setup if the search for the root device starts.
@@ -1018,13 +1043,41 @@ static int __init channel_subsystem_init_sync(void)
 {
         /* Start initial subchannel evaluation. */
         css_schedule_eval_all();
-        /* Wait for the evaluation of subchannels to finish. */
-        wait_event(css_eval_wq, atomic_read(&css_eval_scheduled) == 0);
-        /* Wait for the subchannel type specific initialization to finish */
-        return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
+        css_complete_work();
+        return 0;
 }
 subsys_initcall_sync(channel_subsystem_init_sync);
 
+#ifdef CONFIG_PROC_FS
+static ssize_t cio_settle_write(struct file *file, const char __user *buf,
+                                size_t count, loff_t *ppos)
+{
+        int ret;
+
+        /* Handle pending CRW's. */
+        crw_wait_for_channel_report();
+        ret = css_complete_work();
+
+        return ret ? ret : count;
+}
+
+static const struct file_operations cio_settle_proc_fops = {
+        .write = cio_settle_write,
+};
+
+static int __init cio_settle_init(void)
+{
+        struct proc_dir_entry *entry;
+
+        entry = proc_create("cio_settle", S_IWUSR, NULL,
+                            &cio_settle_proc_fops);
+        if (!entry)
+                return -ENOMEM;
+        return 0;
+}
+device_initcall(cio_settle_init);
+#endif /*CONFIG_PROC_FS*/
+
 int sch_is_pseudo_sch(struct subchannel *sch)
 {
         return sch == to_css(sch->dev.parent)->pseudo_subchannel;