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 <[email protected]>
Reviewed-by: Jeff Layton <[email protected]>
Signed-off-by: NeilBrown <[email protected]>
Signed-off-by: Chuck Lever <[email protected]>

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);