ipc: simplify ipc initialization

Now that we know that rhashtable_init() will not fail, we can get rid of a
lot of the unnecessary cleanup paths when the call errored out.

[manfred@colorfullife.com: variable name added to util.h to resolve checkpatch warning]
Link: http://lkml.kernel.org/r/20180712185241.4017-11-manfred@colorfullife.com
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Kees Cook <keescook@chromium.org>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/ipc/sem.c b/ipc/sem.c
index cf2ba45..e4df102 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -221,14 +221,14 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
 #define sc_semopm	sem_ctls[2]
 #define sc_semmni	sem_ctls[3]
 
-int sem_init_ns(struct ipc_namespace *ns)
+void sem_init_ns(struct ipc_namespace *ns)
 {
 	ns->sc_semmsl = SEMMSL;
 	ns->sc_semmns = SEMMNS;
 	ns->sc_semopm = SEMOPM;
 	ns->sc_semmni = SEMMNI;
 	ns->used_sems = 0;
-	return ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
+	ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
 }
 
 #ifdef CONFIG_IPC_NS
@@ -240,14 +240,12 @@ void sem_exit_ns(struct ipc_namespace *ns)
 }
 #endif
 
-int __init sem_init(void)
+void __init sem_init(void)
 {
-	const int err = sem_init_ns(&init_ipc_ns);
-
+	sem_init_ns(&init_ipc_ns);
 	ipc_init_proc_interface("sysvipc/sem",
 				"       key      semid perms      nsems   uid   gid  cuid  cgid      otime      ctime\n",
 				IPC_SEM_IDS, sysvipc_sem_proc_show);
-	return err;
 }
 
 /**