[S390] cio: introduce css_eval_scheduled

Use css_eval_scheduled to determine if all scheduled subchannel
evaluation is finished. Wait for this value to be 0 in the
channel subsystem init function.

Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 27 insertions, 0 deletions

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index 95805da2bb26..59c4b94cdb4b 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -409,10 +409,14 @@ static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 
 static struct idset *slow_subchannel_set;
 static spinlock_t slow_subchannel_lock;
+static wait_queue_head_t css_eval_wq;
+static atomic_t css_eval_scheduled;
 
 static int __init slow_subchannel_init(void)
 {
         spin_lock_init(&slow_subchannel_lock);
+        atomic_set(&css_eval_scheduled, 0);
+        init_waitqueue_head(&css_eval_wq);
         slow_subchannel_set = idset_sch_new();
         if (!slow_subchannel_set) {
                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
@@ -468,9 +472,17 @@ static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 
 static void css_slow_path_func(struct work_struct *unused)
 {
+        unsigned long flags;
+
         CIO_TRACE_EVENT(4, "slowpath");
         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
                                    NULL);
+        spin_lock_irqsave(&slow_subchannel_lock, flags);
+        if (idset_is_empty(slow_subchannel_set)) {
+                atomic_set(&css_eval_scheduled, 0);
+                wake_up(&css_eval_wq);
+        }
+        spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 }
 
 static DECLARE_WORK(slow_path_work, css_slow_path_func);
@@ -482,6 +494,7 @@ 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);
         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 }
@@ -492,6 +505,7 @@ 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);
         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 }
@@ -1007,6 +1021,8 @@ static int __init channel_subsystem_init_sync(void)
 {
         /* Allocate and register subchannels. */
         for_each_subchannel(setup_subchannel, NULL);
+        /* Wait for the evaluation of subchannels to finish. */
+        wait_event(css_eval_wq, atomic_read(&css_eval_scheduled) == 0);
 
         /* Wait for the initialization of ccw devices to finish. */
         wait_event(ccw_device_init_wq,
diff --git a/drivers/s390/cio/idset.c b/drivers/s390/cio/idset.c
index cf8f24a4b5eb..77e42cb127bb 100644
--- a/drivers/s390/cio/idset.c
+++ b/drivers/s390/cio/idset.c
@@ -110,3 +110,13 @@ int idset_sch_get_first(struct idset *set, struct subchannel_id *schid)
         }
         return rc;
 }
+
+int idset_is_empty(struct idset *set)
+{
+        int bitnum;
+
+        bitnum = find_first_bit(set->bitmap, set->num_ssid * set->num_id);
+        if (bitnum >= set->num_ssid * set->num_id)
+                return 1;
+        return 0;
+}
diff --git a/drivers/s390/cio/idset.h b/drivers/s390/cio/idset.h
index 528065cb5021..ca1398aadc7e 100644
--- a/drivers/s390/cio/idset.h
+++ b/drivers/s390/cio/idset.h
@@ -21,5 +21,6 @@ void idset_sch_add(struct idset *set, struct subchannel_id id);
 void idset_sch_del(struct idset *set, struct subchannel_id id);
 int idset_sch_contains(struct idset *set, struct subchannel_id id);
 int idset_sch_get_first(struct idset *set, struct subchannel_id *id);
+int idset_is_empty(struct idset *set);
 
 #endif /* S390_IDSET_H */