nfsd: don't call functions with side-effecting inside WARN_ON()

Code like:

    WARN_ON(foo())

looks like an assertion and might not be expected to have any side
effects.
When testing if a function with side-effects fails a construct like

    if (foo())
       WARN_ON(1);

makes the intent more obvious.

nfsd has several WARN_ON calls where the test has side effects, so it
would be good to change them.  These cases don't really need the
WARN_ON.  They have never failed in 8 years of usage so let's just
remove the WARN_ON wrapper.
Suggested-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4state.c

@@ -1600,7 +1600,7 @@ static void release_open_stateid_locks(struct nfs4_ol_stateid *open_stp,
 	while (!list_empty(&open_stp->st_locks)) {
 		stp = list_entry(open_stp->st_locks.next,
 				struct nfs4_ol_stateid, st_locks);
-		WARN_ON(!unhash_lock_stateid(stp));
+		unhash_lock_stateid(stp);
 		put_ol_stateid_locked(stp, reaplist);
 	}
 }
@@ -2229,7 +2229,7 @@ __destroy_client(struct nfs4_client *clp)
 	spin_lock(&state_lock);
 	while (!list_empty(&clp->cl_delegations)) {
 		dp = list_entry(clp->cl_delegations.next, struct nfs4_delegation, dl_perclnt);
-		WARN_ON(!unhash_delegation_locked(dp));
+		unhash_delegation_locked(dp);
 		list_add(&dp->dl_recall_lru, &reaplist);
 	}
 	spin_unlock(&state_lock);
@@ -6169,7 +6169,7 @@ nfs4_laundromat(struct nfsd_net *nn)
 		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
 		if (!state_expired(&lt, dp->dl_time))
 			break;
-		WARN_ON(!unhash_delegation_locked(dp));
+		unhash_delegation_locked(dp);
 		list_add(&dp->dl_recall_lru, &reaplist);
 	}
 	spin_unlock(&state_lock);
@@ -7999,7 +7999,7 @@ nfsd4_release_lockowner(struct svc_rqst *rqstp,
 		stp = list_first_entry(&lo->lo_owner.so_stateids,
 				       struct nfs4_ol_stateid,
 				       st_perstateowner);
-		WARN_ON(!unhash_lock_stateid(stp));
+		unhash_lock_stateid(stp);
 		put_ol_stateid_locked(stp, &reaplist);
 	}
 	spin_unlock(&clp->cl_lock);
@@ -8292,7 +8292,7 @@ nfs4_state_shutdown_net(struct net *net)
 	spin_lock(&state_lock);
 	list_for_each_safe(pos, next, &nn->del_recall_lru) {
 		dp = list_entry (pos, struct nfs4_delegation, dl_recall_lru);
-		WARN_ON(!unhash_delegation_locked(dp));
+		unhash_delegation_locked(dp);
 		list_add(&dp->dl_recall_lru, &reaplist);
 	}
 	spin_unlock(&state_lock);