2 files changed, 93 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 02e2115323e4..70057b63de21 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -1627,6 +1627,11 @@ static void of_node_release(struct kref *kref)
                 kfree(prop->value);
                 kfree(prop);
                 prop = next;
+
+                if (!prop) {
+                        prop = node->deadprops;
+                        node->deadprops = NULL;
+                }
         }
         kfree(node->intrs);
         kfree(node->full_name);
@@ -1783,13 +1788,16 @@ unsigned char *get_property(struct device_node *np, const char *name,
 {
         struct property *pp;
 
+        read_lock(&devtree_lock);
         for (pp = np->properties; pp != 0; pp = pp->next)
                 if (strcmp(pp->name, name) == 0) {
                         if (lenp != 0)
                                 *lenp = pp->length;
-                        return pp->value;
+                        break;
                 }
-        return NULL;
+        read_unlock(&devtree_lock);
+
+        return pp ? pp->value : NULL;
 }
 EXPORT_SYMBOL(get_property);
 
@@ -1823,4 +1831,82 @@ int prom_add_property(struct device_node* np, struct property* prop)
         return 0;
 }
 
+/*
+ * Remove a property from a node.  Note that we don't actually
+ * remove it, since we have given out who-knows-how-many pointers
+ * to the data using get-property.  Instead we just move the property
+ * to the "dead properties" list, so it won't be found any more.
+ */
+int prom_remove_property(struct device_node *np, struct property *prop)
+{
+        struct property **next;
+        int found = 0;
+
+        write_lock(&devtree_lock);
+        next = &np->properties;
+        while (*next) {
+                if (*next == prop) {
+                        /* found the node */
+                        *next = prop->next;
+                        prop->next = np->deadprops;
+                        np->deadprops = prop;
+                        found = 1;
+                        break;
+                }
+                next = &(*next)->next;
+        }
+        write_unlock(&devtree_lock);
+
+        if (!found)
+                return -ENODEV;
+
+#ifdef CONFIG_PROC_DEVICETREE
+        /* try to remove the proc node as well */
+        if (np->pde)
+                proc_device_tree_remove_prop(np->pde, prop);
+#endif /* CONFIG_PROC_DEVICETREE */
+
+        return 0;
+}
+
+/*
+ * Update a property in a node.  Note that we don't actually
+ * remove it, since we have given out who-knows-how-many pointers
+ * to the data using get-property.  Instead we just move the property
+ * to the "dead properties" list, and add the new property to the
+ * property list
+ */
+int prom_update_property(struct device_node *np,
+                         struct property *newprop,
+                         struct property *oldprop)
+{
+        struct property **next;
+        int found = 0;
+
+        write_lock(&devtree_lock);
+        next = &np->properties;
+        while (*next) {
+                if (*next == oldprop) {
+                        /* found the node */
+                        newprop->next = oldprop->next;
+                        *next = newprop;
+                        oldprop->next = np->deadprops;
+                        np->deadprops = oldprop;
+                        found = 1;
+                        break;
+                }
+                next = &(*next)->next;
+        }
+        write_unlock(&devtree_lock);
+
+        if (!found)
+                return -ENODEV;
 
+#ifdef CONFIG_PROC_DEVICETREE
+        /* try to add to proc as well if it was initialized */
+        if (np->pde)
+                proc_device_tree_update_prop(np->pde, newprop, oldprop);
+#endif /* CONFIG_PROC_DEVICETREE */
+
+        return 0;
+}
diff --git a/include/asm-powerpc/prom.h b/include/asm-powerpc/prom.h
index 329e9bf62260..25d8d5974d19 100644
--- a/include/asm-powerpc/prom.h
+++ b/include/asm-powerpc/prom.h
@@ -87,6 +87,7 @@ struct device_node {
         char    *full_name;
 
         struct  property *properties;
+        struct  property *deadprops; /* removed properties */
         struct  device_node *parent;
         struct  device_node *child;
         struct  device_node *sibling;
@@ -164,6 +165,10 @@ extern int prom_n_size_cells(struct device_node* np);
 extern int prom_n_intr_cells(struct device_node* np);
 extern void prom_get_irq_senses(unsigned char *senses, int off, int max);
 extern int prom_add_property(struct device_node* np, struct property* prop);
+extern int prom_remove_property(struct device_node *np, struct property *prop);
+extern int prom_update_property(struct device_node *np,
+                                struct property *newprop,
+                                struct property *oldprop);
 
 #ifdef CONFIG_PPC32
 /*