kobject: kobject_uevent() returns manageable value

Since kobject_uevent() function does not return an integer value to
indicate if its operation was completed with success or not, it is worth
changing it in order to report a proper status (success or error) instead
of returning void.

[randy.dunlap@oracle.com: Fix inline kobject functions]
Cc: Mauricio Lin <mauriciolin@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@gmail.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 36 insertions, 19 deletions

diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index d1c8d28fa92e..76538fcf2c4e 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -265,8 +265,8 @@ extern int __must_check subsys_create_file(struct subsystem * ,
                                         struct subsys_attribute *);
 
 #if defined(CONFIG_HOTPLUG)
-void kobject_uevent(struct kobject *kobj, enum kobject_action action);
-void kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
+int kobject_uevent(struct kobject *kobj, enum kobject_action action);
+int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
                         char *envp[]);
 
 int add_uevent_var(char **envp, int num_envp, int *cur_index,
@@ -274,11 +274,12 @@ int add_uevent_var(char **envp, int num_envp, int *cur_index,
                         const char *format, ...)
         __attribute__((format (printf, 7, 8)));
 #else
-static inline void kobject_uevent(struct kobject *kobj, enum kobject_action action) { }
-static inline void kobject_uevent_env(struct kobject *kobj,
+static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
+{ return 0; }
+static inline int kobject_uevent_env(struct kobject *kobj,
                                       enum kobject_action action,
                                       char *envp[])
-{ }
+{ return 0; }
 
 static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
                                       char *buffer, int buffer_size, int *cur_len, 
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index a1922765ff31..84272ed77f03 100644
--- a/lib/kobject_uevent.c
+++ b/lib/kobject_uevent.c
@@ -63,8 +63,11 @@ static char *action_to_string(enum kobject_action action)
  * @action: action that is happening (usually KOBJ_MOVE)
  * @kobj: struct kobject that the action is happening to
  * @envp_ext: pointer to environmental data
+ *
+ * Returns 0 if kobject_uevent() is completed with success or the
+ * corresponding error when it fails.
  */
-void kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
+int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
                         char *envp_ext[])
 {
         char **envp;
@@ -79,14 +82,16 @@ void kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
         u64 seq;
         char *seq_buff;
         int i = 0;
-        int retval;
+        int retval = 0;
         int j;
 
         pr_debug("%s\n", __FUNCTION__);
 
         action_string = action_to_string(action);
-        if (!action_string)
-                return;
+        if (!action_string) {
+                pr_debug("kobject attempted to send uevent without action_string!\n");
+                return -EINVAL;
+        }
 
         /* search the kset we belong to */
         top_kobj = kobj;
@@ -95,31 +100,39 @@ void kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
                         top_kobj = top_kobj->parent;
                 } while (!top_kobj->kset && top_kobj->parent);
         }
-        if (!top_kobj->kset)
-                return;
+        if (!top_kobj->kset) {
+                pr_debug("kobject attempted to send uevent without kset!\n");
+                return -EINVAL;
+        }
 
         kset = top_kobj->kset;
         uevent_ops = kset->uevent_ops;
 
         /*  skip the event, if the filter returns zero. */
         if (uevent_ops && uevent_ops->filter)
-                if (!uevent_ops->filter(kset, kobj))
-                        return;
+                if (!uevent_ops->filter(kset, kobj)) {
+                        pr_debug("kobject filter function caused the event to drop!\n");
+                        return 0;
+                }
 
         /* environment index */
         envp = kzalloc(NUM_ENVP * sizeof (char *), GFP_KERNEL);
         if (!envp)
-                return;
+                return -ENOMEM;
 
         /* environment values */
         buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
-        if (!buffer)
+        if (!buffer) {
+                retval = -ENOMEM;
                 goto exit;
+        }
 
         /* complete object path */
         devpath = kobject_get_path(kobj, GFP_KERNEL);
-        if (!devpath)
+        if (!devpath) {
+                retval = -ENOENT;
                 goto exit;
+        }
 
         /* originating subsystem */
         if (uevent_ops && uevent_ops->name)
@@ -204,7 +217,7 @@ exit:
         kfree(devpath);
         kfree(buffer);
         kfree(envp);
-        return;
+        return retval;
 }
 
 EXPORT_SYMBOL_GPL(kobject_uevent_env);
@@ -214,10 +227,13 @@ EXPORT_SYMBOL_GPL(kobject_uevent_env);
  *
  * @action: action that is happening (usually KOBJ_ADD and KOBJ_REMOVE)
  * @kobj: struct kobject that the action is happening to
+ *
+ * Returns 0 if kobject_uevent() is completed with success or the
+ * corresponding error when it fails.
  */
-void kobject_uevent(struct kobject *kobj, enum kobject_action action)
+int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 {
-        kobject_uevent_env(kobj, action, NULL);
+        return kobject_uevent_env(kobj, action, NULL);
 }
 
 EXPORT_SYMBOL_GPL(kobject_uevent);