[PATCH] kobject: kobject_uevent() returns manageable value

From: Aneesh Kumar K.V
Date: Tue Dec 12 2006 - 04:29:26 EST


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.

CC: Mauricio Lin <mauriciolin@xxxxxxxxx>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxx>
---
include/linux/kobject.h | 8 ++++----
lib/kobject_uevent.c | 44 ++++++++++++++++++++++++++++++--------------
2 files changed, 34 insertions(+), 18 deletions(-)

diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index d1c8d28..fc93c53 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,
@@ -274,8 +274,8 @@ 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) { }
+static inline int kobject_uevent_env(struct kobject *kobj,
enum kobject_action action,
char *envp[])
{ }
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
index a192276..84272ed 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);
--
1.4.4.2.gdb98-dirty