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Commit 1c92b4e5 authored by David S. Miller's avatar David S. Miller
Browse files

[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: default avatarDavid S. Miller <davem@davemloft.net>
parent c1a13ff5

include/net/af_unix.h

+3 −5
Original line number Diff line number Diff line
@@ -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

+47 −47
Original line number Diff line number Diff line
@@ -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 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 
		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 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 
		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 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 
	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 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, 
	 * 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 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 
			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 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 
		 *	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 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock, 
	}



	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');

	}