RPC,NFS: remove instances of tests for waitqueue_active(). Those can be racy.

RPC: remove unnecessary support for sk->sk_sleep on those sockets that are
  owned by the RPC client.

include/linux/nfs_page.h

@@ -100,7 +100,6 @@ nfs_unlock_request(struct nfs_page *req)
 	smp_mb__before_clear_bit();
 	clear_bit(PG_BUSY, &req->wb_flags);
 	smp_mb__after_clear_bit();
-	if (waitqueue_active(&req->wb_wait))
 	wake_up_all(&req->wb_wait);
 	nfs_release_request(req);
 }

net/sunrpc/sched.c

@@ -255,12 +255,10 @@ rpc_make_runnable(struct rpc_task *task)
 				return;
 			}
 			rpc_clear_sleeping(task);
-			if (waitqueue_active(&rpciod_idle))
 			wake_up(&rpciod_idle);
 		}
 	} else {
 		rpc_clear_sleeping(task);
-		if (waitqueue_active(&task->tk_wait))
 		wake_up(&task->tk_wait);
 	}
 }
@@ -287,7 +285,6 @@ void rpciod_wake_up(void)
 {
 	if(rpciod_pid==0)
 		printk(KERN_ERR "rpciod: wot no daemon?\n");
-	if (waitqueue_active(&rpciod_idle))
 	wake_up(&rpciod_idle);
 }
 

net/sunrpc/xprt.c

@@ -782,8 +782,6 @@ udp_data_ready(struct sock *sk, int len)
  dropit:
 	skb_free_datagram(sk, skb);
  out:
-	if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
-		wake_up_interruptible(sk->sk_sleep);
 	read_unlock(&sk->sk_callback_lock);
 }
 
@@ -1043,8 +1041,6 @@ tcp_state_change(struct sock *sk)
 		break;
 	}
  out:
-	if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
-		wake_up_interruptible_all(sk->sk_sleep);
 	read_unlock(&sk->sk_callback_lock);
 }
 
@@ -1084,8 +1080,6 @@ xprt_write_space(struct sock *sk)
 	if (xprt->snd_task && xprt->snd_task->tk_rpcwait == &xprt->pending)
 		rpc_wake_up_task(xprt->snd_task);
 	spin_unlock_bh(&xprt->sock_lock);
-	if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
-		wake_up_interruptible(sk->sk_sleep);
 out:
 	read_unlock(&sk->sk_callback_lock);
 }
@@ -1626,7 +1620,6 @@ xprt_shutdown(struct rpc_xprt *xprt)
 	rpc_wake_up(&xprt->resend);
 	rpc_wake_up(&xprt->pending);
 	rpc_wake_up(&xprt->backlog);
-	if (waitqueue_active(&xprt->cong_wait))
 	wake_up(&xprt->cong_wait);
 	del_timer_sync(&xprt->timer);
 }
@@ -1637,7 +1630,6 @@ xprt_shutdown(struct rpc_xprt *xprt)
 int
 xprt_clear_backlog(struct rpc_xprt *xprt) {
 	rpc_wake_up_next(&xprt->backlog);
-	if (waitqueue_active(&xprt->cong_wait))
 	wake_up(&xprt->cong_wait);
 	return 1;
 }