ipc: rename ipcctl_pre_down_nolock()

Both the comment and the name of ipcctl_pre_down_nolock() are misleading:
The function must be called while holdling the rw semaphore.

Therefore the patch renames the function to ipcctl_obtain_check(): This
name matches the other names used in util.c:

- "obtain" function look up a pointer in the idr, without
  acquiring the object lock.
- The caller is responsible for locking.
- _check means that the sequence number is checked.

Link: http://lkml.kernel.org/r/20180712185241.4017-5-manfred@colorfullife.com
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Reviewed-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
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>

1 files changed, 1 insertions, 1 deletions

diff --git a/ipc/sem.c b/ipc/sem.c
index 8e72037b894a..cf2ba4509f0d 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -1596,7 +1596,7 @@ static int semctl_down(struct ipc_namespace *ns, int semid,
 	down_write(&sem_ids(ns).rwsem);
 	rcu_read_lock();
 
-	ipcp = ipcctl_pre_down_nolock(ns, &sem_ids(ns), semid, cmd,
+	ipcp = ipcctl_obtain_check(ns, &sem_ids(ns), semid, cmd,
 				      &semid64->sem_perm, 0);
 	if (IS_ERR(ipcp)) {
 		err = PTR_ERR(ipcp);