kobject_uevent: remove unneeded netlink_ns check

Back when I rewrote large chunks of uevent sending I should have removed
the .netlink_ns method completely after having removed it's last user in
[1]. Let's remove it now and also remove the helper associated with it
that is unused too.

Fixes: a349843 ("netns: restrict uevents") /* No backport needed. */
Cc: Greg Kroah-Hartman <[email protected]>
Cc: "David S. Miller" <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
---
/* v2 */
unchanged

Documentation/filesystems/sysfs-tagging.txt

@@ -37,6 +37,5 @@ Users of this interface:
 - define a type in the kobj_ns_type enumeration.
 - call kobj_ns_type_register() with its kobj_ns_type_operations which has
   - current_ns() which returns current's namespace
-  - netlink_ns() which returns a socket's namespace
   - initial_ns() which returns the initial namesapce
 - call kobj_ns_exit() when an individual tag is no longer valid

include/linux/kobject_ns.h

@@ -32,15 +32,13 @@ enum kobj_ns_type {
 /*
  * Callbacks so sysfs can determine namespaces
  *   @grab_current_ns: return a new reference to calling task's namespace
- *   @netlink_ns: return namespace to which a sock belongs (right?)
  *   @initial_ns: return the initial namespace (i.e. init_net_ns)
  *   @drop_ns: drops a reference to namespace
  */
 struct kobj_ns_type_operations {
 	enum kobj_ns_type type;
 	bool (*current_may_mount)(void);
 	void *(*grab_current_ns)(void);
-	const void *(*netlink_ns)(struct sock *sk);
 	const void *(*initial_ns)(void);
 	void (*drop_ns)(void *);
 };
@@ -52,7 +50,6 @@ const struct kobj_ns_type_operations *kobj_ns_ops(struct kobject *kobj);
 
 bool kobj_ns_current_may_mount(enum kobj_ns_type type);
 void *kobj_ns_grab_current(enum kobj_ns_type type);
-const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk);
 const void *kobj_ns_initial(enum kobj_ns_type type);
 void kobj_ns_drop(enum kobj_ns_type type, void *ns);
 

lib/kobject.c

@@ -1092,19 +1092,6 @@ void *kobj_ns_grab_current(enum kobj_ns_type type)
 }
 EXPORT_SYMBOL_GPL(kobj_ns_grab_current);
 
-const void *kobj_ns_netlink(enum kobj_ns_type type, struct sock *sk)
-{
-	const void *ns = NULL;
-
-	spin_lock(&kobj_ns_type_lock);
-	if ((type > KOBJ_NS_TYPE_NONE) && (type < KOBJ_NS_TYPES) &&
-	    kobj_ns_ops_tbl[type])
-		ns = kobj_ns_ops_tbl[type]->netlink_ns(sk);
-	spin_unlock(&kobj_ns_type_lock);
-
-	return ns;
-}
-
 const void *kobj_ns_initial(enum kobj_ns_type type)
 {
 	const void *ns = NULL;

lib/kobject_uevent.c

@@ -400,7 +400,7 @@ static int kobject_uevent_net_broadcast(struct kobject *kobj,
 	 * are the only tag relevant here since we want to decide which
 	 * network namespaces to broadcast the uevent into.
 	 */
-	if (ops && ops->netlink_ns && kobj->ktype->namespace)
+	if (ops && kobj->ktype->namespace)
 		if (ops->type == KOBJ_NS_TYPE_NET)
 			net = kobj->ktype->namespace(kobj);
 

net/core/net-sysfs.c

@@ -1694,16 +1694,10 @@ static const void *net_initial_ns(void)
 	return &init_net;
 }
 
-static const void *net_netlink_ns(struct sock *sk)
-{
-	return sock_net(sk);
-}
-
 const struct kobj_ns_type_operations net_ns_type_operations = {
 	.type = KOBJ_NS_TYPE_NET,
 	.current_may_mount = net_current_may_mount,
 	.grab_current_ns = net_grab_current_ns,
-	.netlink_ns = net_netlink_ns,
 	.initial_ns = net_initial_ns,
 	.drop_ns = net_drop_ns,
 };