[AF_UNIX]: Make socket locking much less confusing.

The unix_state_*() locking macros imply that there is some
rwlock kind of thing going on, but the implementation is
actually a spinlock which makes the code more confusing than
it needs to be.

So use plain unix_state_lock and unix_state_unlock.
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/af_unix.h

@@ -62,13 +62,11 @@ struct unix_skb_parms {
 #define UNIXCREDS(skb)	(&UNIXCB((skb)).creds)
 #define UNIXSID(skb)	(&UNIXCB((skb)).secid)
 
-#define unix_state_rlock(s)	spin_lock(&unix_sk(s)->lock)
-#define unix_state_runlock(s)	spin_unlock(&unix_sk(s)->lock)
-#define unix_state_wlock(s)	spin_lock(&unix_sk(s)->lock)
-#define unix_state_wlock_nested(s) \
+#define unix_state_lock(s)	spin_lock(&unix_sk(s)->lock)
+#define unix_state_unlock(s)	spin_unlock(&unix_sk(s)->lock)
+#define unix_state_lock_nested(s) \
 				spin_lock_nested(&unix_sk(s)->lock, \
 				SINGLE_DEPTH_NESTING)
-#define unix_state_wunlock(s)	spin_unlock(&unix_sk(s)->lock)
 
 #ifdef __KERNEL__
 /* The AF_UNIX socket */

net/unix/af_unix.c

@@ -174,11 +174,11 @@ static struct sock *unix_peer_get(struct sock *s)
 {
 	struct sock *peer;
 
-	unix_state_rlock(s);
+	unix_state_lock(s);
 	peer = unix_peer(s);
 	if (peer)
 		sock_hold(peer);
-	unix_state_runlock(s);
+	unix_state_unlock(s);
 	return peer;
 }
 
@@ -369,7 +369,7 @@ static int unix_release_sock (struct sock *sk, int embrion)
 	unix_remove_socket(sk);
 
 	/* Clear state */
-	unix_state_wlock(sk);
+	unix_state_lock(sk);
 	sock_orphan(sk);
 	sk->sk_shutdown = SHUTDOWN_MASK;
 	dentry	     = u->dentry;
@@ -378,7 +378,7 @@ static int unix_release_sock (struct sock *sk, int embrion)
 	u->mnt	     = NULL;
 	state = sk->sk_state;
 	sk->sk_state = TCP_CLOSE;
-	unix_state_wunlock(sk);
+	unix_state_unlock(sk);
 
 	wake_up_interruptible_all(&u->peer_wait);
 
@@ -386,12 +386,12 @@ static int unix_release_sock (struct sock *sk, int embrion)
 
 	if (skpair!=NULL) {
 		if (sk->sk_type == SOCK_STREAM || sk->sk_type == SOCK_SEQPACKET) {
-			unix_state_wlock(skpair);
+			unix_state_lock(skpair);
 			/* No more writes */
 			skpair->sk_shutdown = SHUTDOWN_MASK;
 			if (!skb_queue_empty(&sk->sk_receive_queue) || embrion)
 				skpair->sk_err = ECONNRESET;
-			unix_state_wunlock(skpair);
+			unix_state_unlock(skpair);
 			skpair->sk_state_change(skpair);
 			read_lock(&skpair->sk_callback_lock);
 			sk_wake_async(skpair,1,POLL_HUP);
@@ -448,7 +448,7 @@ static int unix_listen(struct socket *sock, int backlog)
 	err = -EINVAL;
 	if (!u->addr)
 		goto out;			/* No listens on an unbound socket */
-	unix_state_wlock(sk);
+	unix_state_lock(sk);
 	if (sk->sk_state != TCP_CLOSE && sk->sk_state != TCP_LISTEN)
 		goto out_unlock;
 	if (backlog > sk->sk_max_ack_backlog)
@@ -462,7 +462,7 @@ static int unix_listen(struct socket *sock, int backlog)
 	err = 0;
 
 out_unlock:
-	unix_state_wunlock(sk);
+	unix_state_unlock(sk);
 out:
 	return err;
 }
@@ -881,7 +881,7 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
 		if (!other)
 			goto out;
 
-		unix_state_wlock(sk);
+		unix_state_lock(sk);
 
 		err = -EPERM;
 		if (!unix_may_send(sk, other))
@@ -896,7 +896,7 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
 		 *	1003.1g breaking connected state with AF_UNSPEC
 		 */
 		other = NULL;
-		unix_state_wlock(sk);
+		unix_state_lock(sk);
 	}
 
 	/*
@@ -905,19 +905,19 @@ static int unix_dgram_connect(struct socket *sock, struct sockaddr *addr,
 	if (unix_peer(sk)) {
 		struct sock *old_peer = unix_peer(sk);
 		unix_peer(sk)=other;
-		unix_state_wunlock(sk);
+		unix_state_unlock(sk);
 
 		if (other != old_peer)
 			unix_dgram_disconnected(sk, old_peer);
 		sock_put(old_peer);
 	} else {
 		unix_peer(sk)=other;
-		unix_state_wunlock(sk);
+		unix_state_unlock(sk);
 	}
 	return 0;
 
 out_unlock:
-	unix_state_wunlock(sk);
+	unix_state_unlock(sk);
 	sock_put(other);
 out:
 	return err;
@@ -936,7 +936,7 @@ static long unix_wait_for_peer(struct sock *other, long timeo)
 		(skb_queue_len(&other->sk_receive_queue) >
 		 other->sk_max_ack_backlog);
 
-	unix_state_runlock(other);
+	unix_state_unlock(other);
 
 	if (sched)
 		timeo = schedule_timeout(timeo);
@@ -994,11 +994,11 @@ restart:
 		goto out;
 
 	/* Latch state of peer */
-	unix_state_rlock(other);
+	unix_state_lock(other);
 
 	/* Apparently VFS overslept socket death. Retry. */
 	if (sock_flag(other, SOCK_DEAD)) {
-		unix_state_runlock(other);
+		unix_state_unlock(other);
 		sock_put(other);
 		goto restart;
 	}
@@ -1048,18 +1048,18 @@ restart:
 		goto out_unlock;
 	}
 
-	unix_state_wlock_nested(sk);
+	unix_state_lock_nested(sk);
 
 	if (sk->sk_state != st) {
-		unix_state_wunlock(sk);
-		unix_state_runlock(other);
+		unix_state_unlock(sk);
+		unix_state_unlock(other);
 		sock_put(other);
 		goto restart;
 	}
 
 	err = security_unix_stream_connect(sock, other->sk_socket, newsk);
 	if (err) {
-		unix_state_wunlock(sk);
+		unix_state_unlock(sk);
 		goto out_unlock;
 	}
 
@@ -1096,7 +1096,7 @@ restart:
 	smp_mb__after_atomic_inc();	/* sock_hold() does an atomic_inc() */
 	unix_peer(sk)	= newsk;
 
-	unix_state_wunlock(sk);
+	unix_state_unlock(sk);
 
 	/* take ten and and send info to listening sock */
 	spin_lock(&other->sk_receive_queue.lock);
@@ -1105,14 +1105,14 @@ restart:
 	 * is installed to listening socket. */
 	atomic_inc(&newu->inflight);
 	spin_unlock(&other->sk_receive_queue.lock);
-	unix_state_runlock(other);
+	unix_state_unlock(other);
 	other->sk_data_ready(other, 0);
 	sock_put(other);
 	return 0;
 
 out_unlock:
 	if (other)
-		unix_state_runlock(other);
+		unix_state_unlock(other);
 
 out:
 	if (skb)
@@ -1178,10 +1178,10 @@ static int unix_accept(struct socket *sock, struct socket *newsock, int flags)
 	wake_up_interruptible(&unix_sk(sk)->peer_wait);
 
 	/* attach accepted sock to socket */
-	unix_state_wlock(tsk);
+	unix_state_lock(tsk);
 	newsock->state = SS_CONNECTED;
 	sock_graft(tsk, newsock);
-	unix_state_wunlock(tsk);
+	unix_state_unlock(tsk);
 	return 0;
 
 out:
@@ -1208,7 +1208,7 @@ static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_
 	}
 
 	u = unix_sk(sk);
-	unix_state_rlock(sk);
+	unix_state_lock(sk);
 	if (!u->addr) {
 		sunaddr->sun_family = AF_UNIX;
 		sunaddr->sun_path[0] = 0;
@@ -1219,7 +1219,7 @@ static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_
 		*uaddr_len = addr->len;
 		memcpy(sunaddr, addr->name, *uaddr_len);
 	}
-	unix_state_runlock(sk);
+	unix_state_unlock(sk);
 	sock_put(sk);
 out:
 	return err;
@@ -1337,7 +1337,7 @@ restart:
 			goto out_free;
 	}
 
-	unix_state_rlock(other);
+	unix_state_lock(other);
 	err = -EPERM;
 	if (!unix_may_send(sk, other))
 		goto out_unlock;
@@ -1347,20 +1347,20 @@ restart:
 		 *	Check with 1003.1g - what should
 		 *	datagram error
 		 */
-		unix_state_runlock(other);
+		unix_state_unlock(other);
 		sock_put(other);
 
 		err = 0;
-		unix_state_wlock(sk);
+		unix_state_lock(sk);
 		if (unix_peer(sk) == other) {
 			unix_peer(sk)=NULL;
-			unix_state_wunlock(sk);
+			unix_state_unlock(sk);
 
 			unix_dgram_disconnected(sk, other);
 			sock_put(other);
 			err = -ECONNREFUSED;
 		} else {
-			unix_state_wunlock(sk);
+			unix_state_unlock(sk);
 		}
 
 		other = NULL;
@@ -1397,14 +1397,14 @@ restart:
 	}
 
 	skb_queue_tail(&other->sk_receive_queue, skb);
-	unix_state_runlock(other);
+	unix_state_unlock(other);
 	other->sk_data_ready(other, len);
 	sock_put(other);
 	scm_destroy(siocb->scm);
 	return len;
 
 out_unlock:
-	unix_state_runlock(other);
+	unix_state_unlock(other);
 out_free:
 	kfree_skb(skb);
 out:
@@ -1494,14 +1494,14 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 			goto out_err;
 		}
 
-		unix_state_rlock(other);
+		unix_state_lock(other);
 
 		if (sock_flag(other, SOCK_DEAD) ||
 		    (other->sk_shutdown & RCV_SHUTDOWN))
 			goto pipe_err_free;
 
 		skb_queue_tail(&other->sk_receive_queue, skb);
-		unix_state_runlock(other);
+		unix_state_unlock(other);
 		other->sk_data_ready(other, size);
 		sent+=size;
 	}
@@ -1512,7 +1512,7 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
 	return sent;
 
 pipe_err_free:
-	unix_state_runlock(other);
+	unix_state_unlock(other);
 	kfree_skb(skb);
 pipe_err:
 	if (sent==0 && !(msg->msg_flags&MSG_NOSIGNAL))
@@ -1641,7 +1641,7 @@ static long unix_stream_data_wait(struct sock * sk, long timeo)
 {
 	DEFINE_WAIT(wait);
 
-	unix_state_rlock(sk);
+	unix_state_lock(sk);
 
 	for (;;) {
 		prepare_to_wait(sk->sk_sleep, &wait, TASK_INTERRUPTIBLE);
@@ -1654,14 +1654,14 @@ static long unix_stream_data_wait(struct sock * sk, long timeo)
 			break;
 
 		set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
-		unix_state_runlock(sk);
+		unix_state_unlock(sk);
 		timeo = schedule_timeout(timeo);
-		unix_state_rlock(sk);
+		unix_state_lock(sk);
 		clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);
 	}
 
 	finish_wait(sk->sk_sleep, &wait);
-	unix_state_runlock(sk);
+	unix_state_unlock(sk);
 	return timeo;
 }
 
@@ -1816,12 +1816,12 @@ static int unix_shutdown(struct socket *sock, int mode)
 	mode = (mode+1)&(RCV_SHUTDOWN|SEND_SHUTDOWN);
 
 	if (mode) {
-		unix_state_wlock(sk);
+		unix_state_lock(sk);
 		sk->sk_shutdown |= mode;
 		other=unix_peer(sk);
 		if (other)
 			sock_hold(other);
-		unix_state_wunlock(sk);
+		unix_state_unlock(sk);
 		sk->sk_state_change(sk);
 
 		if (other &&
@@ -1833,9 +1833,9 @@ static int unix_shutdown(struct socket *sock, int mode)
 				peer_mode |= SEND_SHUTDOWN;
 			if (mode&SEND_SHUTDOWN)
 				peer_mode |= RCV_SHUTDOWN;
-			unix_state_wlock(other);
+			unix_state_lock(other);
 			other->sk_shutdown |= peer_mode;
-			unix_state_wunlock(other);
+			unix_state_unlock(other);
 			other->sk_state_change(other);
 			read_lock(&other->sk_callback_lock);
 			if (peer_mode == SHUTDOWN_MASK)
@@ -1973,7 +1973,7 @@ static int unix_seq_show(struct seq_file *seq, void *v)
 	else {
 		struct sock *s = v;
 		struct unix_sock *u = unix_sk(s);
-		unix_state_rlock(s);
+		unix_state_lock(s);
 
 		seq_printf(seq, "%p: %08X %08X %08X %04X %02X %5lu",
 			s,
@@ -2001,7 +2001,7 @@ static int unix_seq_show(struct seq_file *seq, void *v)
 			for ( ; i < len; i++)
 				seq_putc(seq, u->addr->name->sun_path[i]);
 		}
-		unix_state_runlock(s);
+		unix_state_unlock(s);
 		seq_putc(seq, '\n');
 	}