1 files changed, 164 insertions, 34 deletions

diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c
index c3df2cd009a4..3b45bbe6cce0 100644
--- a/drivers/s390/cio/css.c
+++ b/drivers/s390/cio/css.c
@@ -51,6 +51,62 @@ for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
         return ret;
 }
 
+struct cb_data {
+        void *data;
+        struct idset *set;
+        int (*fn_known_sch)(struct subchannel *, void *);
+        int (*fn_unknown_sch)(struct subchannel_id, void *);
+};
+
+static int call_fn_known_sch(struct device *dev, void *data)
+{
+        struct subchannel *sch = to_subchannel(dev);
+        struct cb_data *cb = data;
+        int rc = 0;
+
+        idset_sch_del(cb->set, sch->schid);
+        if (cb->fn_known_sch)
+                rc = cb->fn_known_sch(sch, cb->data);
+        return rc;
+}
+
+static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
+{
+        struct cb_data *cb = data;
+        int rc = 0;
+
+        if (idset_sch_contains(cb->set, schid))
+                rc = cb->fn_unknown_sch(schid, cb->data);
+        return rc;
+}
+
+int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
+                               int (*fn_unknown)(struct subchannel_id,
+                               void *), void *data)
+{
+        struct cb_data cb;
+        int rc;
+
+        cb.set = idset_sch_new();
+        if (!cb.set)
+                return -ENOMEM;
+        idset_fill(cb.set);
+        cb.data = data;
+        cb.fn_known_sch = fn_known;
+        cb.fn_unknown_sch = fn_unknown;
+        /* Process registered subchannels. */
+        rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
+        if (rc)
+                goto out;
+        /* Process unregistered subchannels. */
+        if (fn_unknown)
+                rc = for_each_subchannel(call_fn_unknown_sch, &cb);
+out:
+        idset_free(cb.set);
+
+        return rc;
+}
+
 static struct subchannel *
 css_alloc_subchannel(struct subchannel_id schid)
 {
@@ -77,7 +133,7 @@ css_alloc_subchannel(struct subchannel_id schid)
          * This is fine even on 64bit since the subchannel is always located
          * under 2G.
          */
-        sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
+        sch->schib.pmcw.intparm = (u32)(addr_t)sch;
         ret = cio_modify(sch);
         if (ret) {
                 kfree(sch->lock);
@@ -237,11 +293,25 @@ get_subchannel_by_schid(struct subchannel_id schid)
         return dev ? to_subchannel(dev) : NULL;
 }
 
+/**
+ * css_sch_is_valid() - check if a subchannel is valid
+ * @schib: subchannel information block for the subchannel
+ */
+int css_sch_is_valid(struct schib *schib)
+{
+        if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
+                return 0;
+        return 1;
+}
+EXPORT_SYMBOL_GPL(css_sch_is_valid);
+
 static int css_get_subchannel_status(struct subchannel *sch)
 {
         struct schib schib;
 
-        if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
+        if (stsch(sch->schid, &schib))
+                return CIO_GONE;
+        if (!css_sch_is_valid(&schib))
                 return CIO_GONE;
         if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
                 return CIO_REVALIDATE;
@@ -293,7 +363,7 @@ static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
                 action = UNREGISTER;
                 if (sch->driver && sch->driver->notify) {
                         spin_unlock_irqrestore(sch->lock, flags);
-                        ret = sch->driver->notify(&sch->dev, event);
+                        ret = sch->driver->notify(sch, event);
                         spin_lock_irqsave(sch->lock, flags);
                         if (ret)
                                 action = NONE;
@@ -349,7 +419,7 @@ static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
                 /* Will be done on the slow path. */
                 return -EAGAIN;
         }
-        if (stsch_err(schid, &schib) || !schib.pmcw.dnv) {
+        if (stsch_err(schid, &schib) || !css_sch_is_valid(&schib)) {
                 /* Unusable - ignore. */
                 return 0;
         }
@@ -388,20 +458,56 @@ static int __init slow_subchannel_init(void)
         return 0;
 }
 
-static void css_slow_path_func(struct work_struct *unused)
+static int slow_eval_known_fn(struct subchannel *sch, void *data)
 {
-        struct subchannel_id schid;
+        int eval;
+        int rc;
 
-        CIO_TRACE_EVENT(4, "slowpath");
         spin_lock_irq(&slow_subchannel_lock);
-        init_subchannel_id(&schid);
-        while (idset_sch_get_first(slow_subchannel_set, &schid)) {
-                idset_sch_del(slow_subchannel_set, schid);
-                spin_unlock_irq(&slow_subchannel_lock);
-                css_evaluate_subchannel(schid, 1);
-                spin_lock_irq(&slow_subchannel_lock);
+        eval = idset_sch_contains(slow_subchannel_set, sch->schid);
+        idset_sch_del(slow_subchannel_set, sch->schid);
+        spin_unlock_irq(&slow_subchannel_lock);
+        if (eval) {
+                rc = css_evaluate_known_subchannel(sch, 1);
+                if (rc == -EAGAIN)
+                        css_schedule_eval(sch->schid);
         }
+        return 0;
+}
+
+static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
+{
+        int eval;
+        int rc = 0;
+
+        spin_lock_irq(&slow_subchannel_lock);
+        eval = idset_sch_contains(slow_subchannel_set, schid);
+        idset_sch_del(slow_subchannel_set, schid);
         spin_unlock_irq(&slow_subchannel_lock);
+        if (eval) {
+                rc = css_evaluate_new_subchannel(schid, 1);
+                switch (rc) {
+                case -EAGAIN:
+                        css_schedule_eval(schid);
+                        rc = 0;
+                        break;
+                case -ENXIO:
+                case -ENOMEM:
+                case -EIO:
+                        /* These should abort looping */
+                        break;
+                default:
+                        rc = 0;
+                }
+        }
+        return rc;
+}
+
+static void css_slow_path_func(struct work_struct *unused)
+{
+        CIO_TRACE_EVENT(4, "slowpath");
+        for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
+                                   NULL);
 }
 
 static DECLARE_WORK(slow_path_work, css_slow_path_func);
@@ -430,7 +536,6 @@ void css_schedule_eval_all(void)
 /* Reprobe subchannel if unregistered. */
 static int reprobe_subchannel(struct subchannel_id schid, void *data)
 {
-        struct subchannel *sch;
         int ret;
 
         CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
@@ -438,13 +543,6 @@ static int reprobe_subchannel(struct subchannel_id schid, void *data)
         if (need_reprobe)
                 return -EAGAIN;
 
-        sch = get_subchannel_by_schid(schid);
-        if (sch) {
-                /* Already known. */
-                put_device(&sch->dev);
-                return 0;
-        }
-
         ret = css_probe_device(schid);
         switch (ret) {
         case 0:
@@ -472,7 +570,7 @@ static void reprobe_all(struct work_struct *unused)
         /* Make sure initial subchannel scan is done. */
         wait_event(ccw_device_init_wq,
                    atomic_read(&ccw_device_init_count) == 0);
-        ret = for_each_subchannel(reprobe_subchannel, NULL);
+        ret = for_each_subchannel_staged(NULL, reprobe_subchannel, NULL);
 
         CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
                       need_reprobe);
@@ -787,8 +885,8 @@ int sch_is_pseudo_sch(struct subchannel *sch)
 static int
 css_bus_match (struct device *dev, struct device_driver *drv)
 {
-        struct subchannel *sch = container_of (dev, struct subchannel, dev);
-        struct css_driver *driver = container_of (drv, struct css_driver, drv);
+        struct subchannel *sch = to_subchannel(dev);
+        struct css_driver *driver = to_cssdriver(drv);
 
         if (sch->st == driver->subchannel_type)
                 return 1;
@@ -796,32 +894,36 @@ css_bus_match (struct device *dev, struct device_driver *drv)
         return 0;
 }
 
-static int
-css_probe (struct device *dev)
+static int css_probe(struct device *dev)
 {
         struct subchannel *sch;
+        int ret;
 
         sch = to_subchannel(dev);
-        sch->driver = container_of (dev->driver, struct css_driver, drv);
-        return (sch->driver->probe ? sch->driver->probe(sch) : 0);
+        sch->driver = to_cssdriver(dev->driver);
+        ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
+        if (ret)
+                sch->driver = NULL;
+        return ret;
 }
 
-static int
-css_remove (struct device *dev)
+static int css_remove(struct device *dev)
 {
         struct subchannel *sch;
+        int ret;
 
         sch = to_subchannel(dev);
-        return (sch->driver->remove ? sch->driver->remove(sch) : 0);
+        ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
+        sch->driver = NULL;
+        return ret;
 }
 
-static void
-css_shutdown (struct device *dev)
+static void css_shutdown(struct device *dev)
 {
         struct subchannel *sch;
 
         sch = to_subchannel(dev);
-        if (sch->driver->shutdown)
+        if (sch->driver && sch->driver->shutdown)
                 sch->driver->shutdown(sch);
 }
 
@@ -833,6 +935,34 @@ struct bus_type css_bus_type = {
         .shutdown = css_shutdown,
 };
 
+/**
+ * css_driver_register - register a css driver
+ * @cdrv: css driver to register
+ *
+ * This is mainly a wrapper around driver_register that sets name
+ * and bus_type in the embedded struct device_driver correctly.
+ */
+int css_driver_register(struct css_driver *cdrv)
+{
+        cdrv->drv.name = cdrv->name;
+        cdrv->drv.bus = &css_bus_type;
+        cdrv->drv.owner = cdrv->owner;
+        return driver_register(&cdrv->drv);
+}
+EXPORT_SYMBOL_GPL(css_driver_register);
+
+/**
+ * css_driver_unregister - unregister a css driver
+ * @cdrv: css driver to unregister
+ *
+ * This is a wrapper around driver_unregister.
+ */
+void css_driver_unregister(struct css_driver *cdrv)
+{
+        driver_unregister(&cdrv->drv);
+}
+EXPORT_SYMBOL_GPL(css_driver_unregister);
+
 subsys_initcall(init_channel_subsystem);
 
 MODULE_LICENSE("GPL");