Merge remote-tracking branch 'chrome-platform/for-next'
[karo-tx-linux.git] / fs / sysfs / group.c
index 51b56e6..dc1358b 100644 (file)
@@ -365,3 +365,47 @@ void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
        }
 }
 EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
+
+/**
+ * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
+ * to a group or an attribute
+ * @kobj:              The kobject containing the group.
+ * @target_kobj:       The target kobject.
+ * @target_name:       The name of the target group or attribute.
+ */
+int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
+                                     struct kobject *target_kobj,
+                                     const char *target_name)
+{
+       struct kernfs_node *target;
+       struct kernfs_node *entry;
+       struct kernfs_node *link;
+
+       /*
+        * We don't own @target_kobj and it may be removed at any time.
+        * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
+        * for details.
+        */
+       spin_lock(&sysfs_symlink_target_lock);
+       target = target_kobj->sd;
+       if (target)
+               kernfs_get(target);
+       spin_unlock(&sysfs_symlink_target_lock);
+       if (!target)
+               return -ENOENT;
+
+       entry = kernfs_find_and_get(target_kobj->sd, target_name);
+       if (!entry) {
+               kernfs_put(target);
+               return -ENOENT;
+       }
+
+       link = kernfs_create_link(kobj->sd, target_name, entry);
+       if (IS_ERR(link) && PTR_ERR(link) == -EEXIST)
+               sysfs_warn_dup(kobj->sd, target_name);
+
+       kernfs_put(entry);
+       kernfs_put(target);
+       return IS_ERR(link) ? PTR_ERR(link) : 0;
+}
+EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);