ipc, shm: drop shm_lock_check

This function was replaced by a the lockless shm_obtain_object_check(),
and no longer has any users.

Signed-off-by: Davidlohr Bueso <[e-mail]>
Cc: Sedat Dilek <[e-mail]>
Cc: Rik van Riel <[e-mail]>
Cc: Manfred Spraul <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

ipc/shm.c

···
 	ipc_lock_object(&ipcp->shm_perm);
 }
 
-static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
-						int id)
-{
-	struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
-
-	if (IS_ERR(ipcp))
-		return (struct shmid_kernel *)ipcp;
-
-	return container_of(ipcp, struct shmid_kernel, shm_perm);
-}
-
 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
 {
 	ipc_rmid(&shm_ids(ns), &s->shm_perm);