Revert "tcp: allow again tcp_disconnect() when threads are waiting"

This reverts commit ec9bc89a01 which is
commit 419ce133ab upstream.

It breaks the android ABI and if this is needed in the future, can be
brought back in an abi-safe way.

Bug: 161946584
Change-Id: I591c4ae39181ebf38284aaeb927e890a08380e2b
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c

@@ -911,7 +911,7 @@ static int csk_wait_memory(struct chtls_dev *cdev,
 			   struct sock *sk, long *timeo_p)
 {
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
-	int ret, err = 0;
+	int err = 0;
 	long current_timeo;
 	long vm_wait = 0;
 	bool noblock;
@@ -942,13 +942,10 @@ static int csk_wait_memory(struct chtls_dev *cdev,
 
 		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 		sk->sk_write_pending++;
-		ret = sk_wait_event(sk, &current_timeo, sk->sk_err ||
-				    (sk->sk_shutdown & SEND_SHUTDOWN) ||
-				    (csk_mem_free(cdev, sk) && !vm_wait),
-				    &wait);
+		sk_wait_event(sk, &current_timeo, sk->sk_err ||
+			      (sk->sk_shutdown & SEND_SHUTDOWN) ||
+			      (csk_mem_free(cdev, sk) && !vm_wait), &wait);
 		sk->sk_write_pending--;
-		if (ret < 0)
-			goto do_error;
 
 		if (vm_wait) {
 			vm_wait -= current_timeo;
@@ -1441,7 +1438,6 @@ static int chtls_pt_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	int copied = 0;
 	int target;
 	long timeo;
-	int ret;
 
 	buffers_freed = 0;
 
@@ -1517,11 +1513,7 @@ static int chtls_pt_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 		if (copied >= target)
 			break;
 		chtls_cleanup_rbuf(sk, copied);
-		ret = sk_wait_data(sk, &timeo, NULL);
-		if (ret < 0) {
-			copied = copied ? : ret;
-			goto unlock;
-		}
+		sk_wait_data(sk, &timeo, NULL);
 		continue;
 found_ok_skb:
 		if (!skb->len) {
@@ -1616,8 +1608,6 @@ skip_copy:
 
 	if (buffers_freed)
 		chtls_cleanup_rbuf(sk, copied);
-
-unlock:
 	release_sock(sk);
 	return copied;
 }
@@ -1634,7 +1624,6 @@ static int peekmsg(struct sock *sk, struct msghdr *msg,
 	int copied = 0;
 	size_t avail;          /* amount of available data in current skb */
 	long timeo;
-	int ret;
 
 	lock_sock(sk);
 	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
@@ -1686,12 +1675,7 @@ static int peekmsg(struct sock *sk, struct msghdr *msg,
 			release_sock(sk);
 			lock_sock(sk);
 		} else {
-			ret = sk_wait_data(sk, &timeo, NULL);
-			if (ret < 0) {
-				/* here 'copied' is 0 due to previous checks */
-				copied = ret;
-				break;
-			}
+			sk_wait_data(sk, &timeo, NULL);
 		}
 
 		if (unlikely(peek_seq != tp->copied_seq)) {
@@ -1762,7 +1746,6 @@ int chtls_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	int copied = 0;
 	long timeo;
 	int target;             /* Read at least this many bytes */
-	int ret;
 
 	buffers_freed = 0;
 
@@ -1854,11 +1837,7 @@ int chtls_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 		if (copied >= target)
 			break;
 		chtls_cleanup_rbuf(sk, copied);
-		ret = sk_wait_data(sk, &timeo, NULL);
-		if (ret < 0) {
-			copied = copied ? : ret;
-			goto unlock;
-		}
+		sk_wait_data(sk, &timeo, NULL);
 		continue;
 
 found_ok_skb:
@@ -1927,7 +1906,6 @@ skip_copy:
 	if (buffers_freed)
 		chtls_cleanup_rbuf(sk, copied);
 
-unlock:
 	release_sock(sk);
 	return copied;
 }

include/net/sock.h

@@ -335,7 +335,7 @@ struct sk_filter;
   *	@sk_cgrp_data: cgroup data for this cgroup
   *	@sk_memcg: this socket's memory cgroup association
   *	@sk_write_pending: a write to stream socket waits to start
-  *	@sk_disconnects: number of disconnect operations performed on this sock
+  *	@sk_wait_pending: number of threads blocked on this socket
   *	@sk_state_change: callback to indicate change in the state of the sock
   *	@sk_data_ready: callback to indicate there is data to be processed
   *	@sk_write_space: callback to indicate there is bf sending space available
@@ -428,7 +428,7 @@ struct sock {
 	unsigned int		sk_napi_id;
 #endif
 	int			sk_rcvbuf;
-	int			sk_disconnects;
+	int			sk_wait_pending;
 
 	struct sk_filter __rcu	*sk_filter;
 	union {
@@ -1197,7 +1197,8 @@ static inline void sock_rps_reset_rxhash(struct sock *sk)
 }
 
 #define sk_wait_event(__sk, __timeo, __condition, __wait)		\
-	({	int __rc, __dis = __sk->sk_disconnects;			\
+	({	int __rc;						\
+		__sk->sk_wait_pending++;				\
 		release_sock(__sk);					\
 		__rc = __condition;					\
 		if (!__rc) {						\
@@ -1207,7 +1208,8 @@ static inline void sock_rps_reset_rxhash(struct sock *sk)
 		}							\
 		sched_annotate_sleep();					\
 		lock_sock(__sk);					\
-		__rc = __dis == __sk->sk_disconnects ? __condition : -EPIPE; \
+		__sk->sk_wait_pending--;				\
+		__rc = __condition;					\
 		__rc;							\
 	})
 

net/core/stream.c

@@ -117,7 +117,7 @@ EXPORT_SYMBOL(sk_stream_wait_close);
  */
 int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
 {
-	int ret, err = 0;
+	int err = 0;
 	long vm_wait = 0;
 	long current_timeo = *timeo_p;
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
@@ -142,13 +142,11 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
 
 		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 		sk->sk_write_pending++;
-		ret = sk_wait_event(sk, &current_timeo, READ_ONCE(sk->sk_err) ||
-				    (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN) ||
-				    (sk_stream_memory_free(sk) && !vm_wait),
-				    &wait);
+		sk_wait_event(sk, &current_timeo, READ_ONCE(sk->sk_err) ||
+						  (READ_ONCE(sk->sk_shutdown) & SEND_SHUTDOWN) ||
+						  (sk_stream_memory_free(sk) &&
+						  !vm_wait), &wait);
 		sk->sk_write_pending--;
-		if (ret < 0)
-			goto do_error;
 
 		if (vm_wait) {
 			vm_wait -= current_timeo;

net/ipv4/af_inet.c

@@ -589,6 +589,7 @@ static long inet_wait_for_connect(struct sock *sk, long timeo, int writebias)
 
 	add_wait_queue(sk_sleep(sk), &wait);
 	sk->sk_write_pending += writebias;
+	sk->sk_wait_pending++;
 
 	/* Basic assumption: if someone sets sk->sk_err, he _must_
 	 * change state of the socket from TCP_SYN_*.
@@ -604,6 +605,7 @@ static long inet_wait_for_connect(struct sock *sk, long timeo, int writebias)
 	}
 	remove_wait_queue(sk_sleep(sk), &wait);
 	sk->sk_write_pending -= writebias;
+	sk->sk_wait_pending--;
 	return timeo;
 }
 
@@ -632,7 +634,6 @@ int __inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
 			return -EINVAL;
 
 		if (uaddr->sa_family == AF_UNSPEC) {
-			sk->sk_disconnects++;
 			err = sk->sk_prot->disconnect(sk, flags);
 			sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
 			goto out;
@@ -687,7 +688,6 @@ int __inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
 		int writebias = (sk->sk_protocol == IPPROTO_TCP) &&
 				tcp_sk(sk)->fastopen_req &&
 				tcp_sk(sk)->fastopen_req->data ? 1 : 0;
-		int dis = sk->sk_disconnects;
 
 		/* Error code is set above */
 		if (!timeo || !inet_wait_for_connect(sk, timeo, writebias))
@@ -696,11 +696,6 @@ int __inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
 		err = sock_intr_errno(timeo);
 		if (signal_pending(current))
 			goto out;
-
-		if (dis != sk->sk_disconnects) {
-			err = -EPIPE;
-			goto out;
-		}
 	}
 
 	/* Connection was closed by RST, timeout, ICMP error
@@ -722,7 +717,6 @@ out:
 sock_error:
 	err = sock_error(sk) ? : -ECONNABORTED;
 	sock->state = SS_UNCONNECTED;
-	sk->sk_disconnects++;
 	if (sk->sk_prot->disconnect(sk, flags))
 		sock->state = SS_DISCONNECTING;
 	goto out;

net/ipv4/inet_connection_sock.c

@@ -1143,6 +1143,7 @@ struct sock *inet_csk_clone_lock(const struct sock *sk,
 	if (newsk) {
 		struct inet_connection_sock *newicsk = inet_csk(newsk);
 
+		newsk->sk_wait_pending = 0;
 		inet_sk_set_state(newsk, TCP_SYN_RECV);
 		newicsk->icsk_bind_hash = NULL;
 		newicsk->icsk_bind2_hash = NULL;

net/ipv4/tcp.c

@@ -827,9 +827,7 @@ ssize_t tcp_splice_read(struct socket *sock, loff_t *ppos,
 			 */
 			if (!skb_queue_empty(&sk->sk_receive_queue))
 				break;
-			ret = sk_wait_data(sk, &timeo, NULL);
-			if (ret < 0)
-				break;
+			sk_wait_data(sk, &timeo, NULL);
 			if (signal_pending(current)) {
 				ret = sock_intr_errno(timeo);
 				break;
@@ -2551,11 +2549,7 @@ static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len,
 			__sk_flush_backlog(sk);
 		} else {
 			tcp_cleanup_rbuf(sk, copied);
-			err = sk_wait_data(sk, &timeo, last);
-			if (err < 0) {
-				err = copied ? : err;
-				goto out;
-			}
+			sk_wait_data(sk, &timeo, last);
 		}
 
 		if ((flags & MSG_PEEK) &&
@@ -3079,6 +3073,12 @@ int tcp_disconnect(struct sock *sk, int flags)
 	int old_state = sk->sk_state;
 	u32 seq;
 
+	/* Deny disconnect if other threads are blocked in sk_wait_event()
+	 * or inet_wait_for_connect().
+	 */
+	if (sk->sk_wait_pending)
+		return -EBUSY;
+
 	if (old_state != TCP_CLOSE)
 		tcp_set_state(sk, TCP_CLOSE);
 

net/ipv4/tcp_bpf.c

@@ -302,8 +302,6 @@ msg_bytes_ready:
 		}
 
 		data = tcp_msg_wait_data(sk, psock, timeo);
-		if (data < 0)
-			return data;
 		if (data && !sk_psock_queue_empty(psock))
 			goto msg_bytes_ready;
 		copied = -EAGAIN;
@@ -348,8 +346,6 @@ msg_bytes_ready:
 
 		timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
 		data = tcp_msg_wait_data(sk, psock, timeo);
-		if (data < 0)
-			return data;
 		if (data) {
 			if (!sk_psock_queue_empty(psock))
 				goto msg_bytes_ready;

net/mptcp/protocol.c

@@ -3117,6 +3117,12 @@ static int mptcp_disconnect(struct sock *sk, int flags)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 
+	/* Deny disconnect if other threads are blocked in sk_wait_event()
+	 * or inet_wait_for_connect().
+	 */
+	if (sk->sk_wait_pending)
+		return -EBUSY;
+
 	/* We are on the fastopen error path. We can't call straight into the
 	 * subflows cleanup code due to lock nesting (we are already under
 	 * msk->firstsocket lock).
@@ -3184,6 +3190,7 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk,
 		inet_sk(nsk)->pinet6 = mptcp_inet6_sk(nsk);
 #endif
 
+	nsk->sk_wait_pending = 0;
 	__mptcp_init_sock(nsk);
 
 	msk = mptcp_sk(nsk);

net/tls/tls_main.c

@@ -96,8 +96,8 @@ void update_sk_prot(struct sock *sk, struct tls_context *ctx)
 
 int wait_on_pending_writer(struct sock *sk, long *timeo)
 {
+	int rc = 0;
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
-	int ret, rc = 0;
 
 	add_wait_queue(sk_sleep(sk), &wait);
 	while (1) {
@@ -111,13 +111,9 @@ int wait_on_pending_writer(struct sock *sk, long *timeo)
 			break;
 		}
 
-		ret = sk_wait_event(sk, timeo,
-				    !READ_ONCE(sk->sk_write_pending), &wait);
-		if (ret) {
-			if (ret < 0)
-				rc = ret;
+		if (sk_wait_event(sk, timeo,
+				  !READ_ONCE(sk->sk_write_pending), &wait))
 			break;
-		}
 	}
 	remove_wait_queue(sk_sleep(sk), &wait);
 	return rc;

net/tls/tls_sw.c

@@ -1296,7 +1296,6 @@ tls_rx_rec_wait(struct sock *sk, struct sk_psock *psock, bool nonblock,
 	struct tls_context *tls_ctx = tls_get_ctx(sk);
 	struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
-	int ret = 0;
 	long timeo;
 
 	timeo = sock_rcvtimeo(sk, nonblock);
@@ -1308,9 +1307,6 @@ tls_rx_rec_wait(struct sock *sk, struct sk_psock *psock, bool nonblock,
 		if (sk->sk_err)
 			return sock_error(sk);
 
-		if (ret < 0)
-			return ret;
-
 		if (!skb_queue_empty(&sk->sk_receive_queue)) {
 			tls_strp_check_rcv(&ctx->strp);
 			if (tls_strp_msg_ready(ctx))
@@ -1329,10 +1325,10 @@ tls_rx_rec_wait(struct sock *sk, struct sk_psock *psock, bool nonblock,
 		released = true;
 		add_wait_queue(sk_sleep(sk), &wait);
 		sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
-		ret = sk_wait_event(sk, &timeo,
-				    tls_strp_msg_ready(ctx) ||
-				    !sk_psock_queue_empty(psock),
-				    &wait);
+		sk_wait_event(sk, &timeo,
+			      tls_strp_msg_ready(ctx) ||
+			      !sk_psock_queue_empty(psock),
+			      &wait);
 		sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 		remove_wait_queue(sk_sleep(sk), &wait);
 
@@ -1859,7 +1855,6 @@ static int tls_rx_reader_acquire(struct sock *sk, struct tls_sw_context_rx *ctx,
 				 bool nonblock)
 {
 	long timeo;
-	int ret;
 
 	timeo = sock_rcvtimeo(sk, nonblock);
 
@@ -1869,16 +1864,14 @@ static int tls_rx_reader_acquire(struct sock *sk, struct tls_sw_context_rx *ctx,
 		ctx->reader_contended = 1;
 
 		add_wait_queue(&ctx->wq, &wait);
-		ret = sk_wait_event(sk, &timeo,
-				    !READ_ONCE(ctx->reader_present), &wait);
+		sk_wait_event(sk, &timeo,
+			      !READ_ONCE(ctx->reader_present), &wait);
 		remove_wait_queue(&ctx->wq, &wait);
 
 		if (timeo <= 0)
 			return -EAGAIN;
 		if (signal_pending(current))
 			return sock_intr_errno(timeo);
-		if (ret < 0)
-			return ret;
 	}
 
 	WRITE_ONCE(ctx->reader_present, 1);