of: Reorder device tree changes and notifiers

Currently, devicetree reconfig notifiers get emitted before the change
is applied to the tree, but that behaviour is problematic if the
receiver wants the determine the new state of the tree. The current
users don't care, but the changeset code to follow will be making
multiple changes at once. Reorder notifiers to get emitted after the
change has been applied to the tree so that callbacks see the new tree
state.

At the same time, fixup the existing callbacks to expect the new order.
There are a few callbacks that compare the old and new values of a
changed property. Put both property pointers into the of_prop_reconfig
structure.

The current notifiers also allow the notifier callback to fail and
cancel the change to the tree, but that feature isn't actually used.
It really isn't valid to ignore a tree modification provided by firmware
anyway, so remove the ability to cancel a change to the tree.

Signed-off-by: Grant Likely <grant.likely@linaro.org>
Cc: Nathan Fontenot <nfont@austin.ibm.com>

3 files changed, 19 insertions, 24 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index ededf8e33145..a7ad1013edfa 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1674,10 +1674,6 @@ int of_add_property(struct device_node *np, struct property *prop)
         unsigned long flags;
         int rc;
 
-        rc = of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop);
-        if (rc)
-                return rc;
-
         mutex_lock(&of_mutex);
 
         raw_spin_lock_irqsave(&devtree_lock, flags);
@@ -1689,6 +1685,9 @@ int of_add_property(struct device_node *np, struct property *prop)
 
         mutex_unlock(&of_mutex);
 
+        if (!rc)
+                of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop, NULL);
+
         return rc;
 }
 
@@ -1731,10 +1730,6 @@ int of_remove_property(struct device_node *np, struct property *prop)
         unsigned long flags;
         int rc;
 
-        rc = of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop);
-        if (rc)
-                return rc;
-
         mutex_lock(&of_mutex);
 
         raw_spin_lock_irqsave(&devtree_lock, flags);
@@ -1746,6 +1741,9 @@ int of_remove_property(struct device_node *np, struct property *prop)
 
         mutex_unlock(&of_mutex);
 
+        if (!rc)
+                of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop, NULL);
+
         return rc;
 }
 
@@ -1805,10 +1803,6 @@ int of_update_property(struct device_node *np, struct property *newprop)
         if (!newprop->name)
                 return -EINVAL;
 
-        rc = of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop);
-        if (rc)
-                return rc;
-
         mutex_lock(&of_mutex);
 
         raw_spin_lock_irqsave(&devtree_lock, flags);
@@ -1820,6 +1814,9 @@ int of_update_property(struct device_node *np, struct property *newprop)
 
         mutex_unlock(&of_mutex);
 
+        if (!rc)
+                of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop, oldprop);
+
         return rc;
 }
 
diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c
index 7c020b9a3317..7bd5501736a6 100644
--- a/drivers/of/dynamic.c
+++ b/drivers/of/dynamic.c
@@ -83,7 +83,7 @@ int of_reconfig_notify(unsigned long action, void *p)
 }
 
 int of_property_notify(int action, struct device_node *np,
-                       struct property *prop)
+                       struct property *prop, struct property *oldprop)
 {
         struct of_prop_reconfig pr;
 
@@ -93,6 +93,7 @@ int of_property_notify(int action, struct device_node *np,
 
         pr.dn = np;
         pr.prop = prop;
+        pr.old_prop = oldprop;
         return of_reconfig_notify(action, &pr);
 }
 
@@ -125,11 +126,6 @@ void __of_attach_node(struct device_node *np)
 int of_attach_node(struct device_node *np)
 {
         unsigned long flags;
-        int rc;
-
-        rc = of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
-        if (rc)
-                return rc;
 
         mutex_lock(&of_mutex);
         raw_spin_lock_irqsave(&devtree_lock, flags);
@@ -138,6 +134,9 @@ int of_attach_node(struct device_node *np)
 
         __of_attach_node_sysfs(np);
         mutex_unlock(&of_mutex);
+
+        of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
+
         return 0;
 }
 
@@ -188,10 +187,6 @@ int of_detach_node(struct device_node *np)
         unsigned long flags;
         int rc = 0;
 
-        rc = of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
-        if (rc)
-                return rc;
-
         mutex_lock(&of_mutex);
         raw_spin_lock_irqsave(&devtree_lock, flags);
         __of_detach_node(np);
@@ -199,6 +194,9 @@ int of_detach_node(struct device_node *np)
 
         __of_detach_node_sysfs(np);
         mutex_unlock(&of_mutex);
+
+        of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
+
         return rc;
 }
 
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index 8129c0e58d70..f69ccb1fa308 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -43,11 +43,11 @@ static inline struct device_node *kobj_to_device_node(struct kobject *kobj)
 
 #if defined(CONFIG_OF_DYNAMIC)
 extern int of_property_notify(int action, struct device_node *np,
-                              struct property *prop);
+                              struct property *prop, struct property *old_prop);
 extern void of_node_release(struct kobject *kobj);
 #else /* CONFIG_OF_DYNAMIC */
 static inline int of_property_notify(int action, struct device_node *np,
-                                     struct property *prop)
+                                     struct property *prop, struct property *old_prop)
 {
         return 0;
 }