Exemple #1
0
int rds_tcp_conn_path_connect(struct rds_conn_path *cp)
{
	struct socket *sock = NULL;
	struct sockaddr_in src, dest;
	int ret;
	struct rds_connection *conn = cp->cp_conn;
	struct rds_tcp_connection *tc = cp->cp_transport_data;

	mutex_lock(&tc->t_conn_path_lock);

	if (rds_conn_path_up(cp)) {
		mutex_unlock(&tc->t_conn_path_lock);
		return 0;
	}
	ret = sock_create_kern(rds_conn_net(conn), PF_INET,
			       SOCK_STREAM, IPPROTO_TCP, &sock);
	if (ret < 0)
		goto out;

	rds_tcp_tune(sock);

	src.sin_family = AF_INET;
	src.sin_addr.s_addr = (__force u32)conn->c_laddr;
	src.sin_port = (__force u16)htons(0);

	ret = sock->ops->bind(sock, (struct sockaddr *)&src, sizeof(src));
	if (ret) {
		rdsdebug("bind failed with %d at address %pI4\n",
			 ret, &conn->c_laddr);
		goto out;
	}

	dest.sin_family = AF_INET;
	dest.sin_addr.s_addr = (__force u32)conn->c_faddr;
	dest.sin_port = (__force u16)htons(RDS_TCP_PORT);

	/*
	 * once we call connect() we can start getting callbacks and they
	 * own the socket
	 */
	rds_tcp_set_callbacks(sock, cp);
	ret = sock->ops->connect(sock, (struct sockaddr *)&dest, sizeof(dest),
				 O_NONBLOCK);

	cp->cp_outgoing = 1;
	rdsdebug("connect to address %pI4 returned %d\n", &conn->c_faddr, ret);
	if (ret == -EINPROGRESS)
		ret = 0;
	if (ret == 0) {
		rds_tcp_keepalive(sock);
		sock = NULL;
	} else {
		rds_tcp_restore_callbacks(sock, cp->cp_transport_data);
	}

out:
	mutex_unlock(&tc->t_conn_path_lock);
	if (sock)
		sock_release(sock);
	return ret;
}
Exemple #2
0
/* the core send_sem serializes this with other xmit and shutdown */
static int rds_tcp_sendmsg(struct socket *sock, void *data, unsigned int len)
{
	struct kvec vec = {
		.iov_base = data,
		.iov_len = len,
	};
	struct msghdr msg = {
		.msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL,
	};

	return kernel_sendmsg(sock, &msg, &vec, 1, vec.iov_len);
}

/* the core send_sem serializes this with other xmit and shutdown */
int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
		 unsigned int hdr_off, unsigned int sg, unsigned int off)
{
	struct rds_conn_path *cp = rm->m_inc.i_conn_path;
	struct rds_tcp_connection *tc = cp->cp_transport_data;
	int done = 0;
	int ret = 0;
	int more;

	if (hdr_off == 0) {
		/*
		 * m_ack_seq is set to the sequence number of the last byte of
		 * header and data.  see rds_tcp_is_acked().
		 */
		tc->t_last_sent_nxt = rds_tcp_snd_nxt(tc);
		rm->m_ack_seq = tc->t_last_sent_nxt +
				sizeof(struct rds_header) +
				be32_to_cpu(rm->m_inc.i_hdr.h_len) - 1;
		smp_mb__before_atomic();
		set_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags);
		tc->t_last_expected_una = rm->m_ack_seq + 1;

		if (test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags))
			rm->m_inc.i_hdr.h_flags |= RDS_FLAG_RETRANSMITTED;

		rdsdebug("rm %p tcp nxt %u ack_seq %llu\n",
			 rm, rds_tcp_snd_nxt(tc),
			 (unsigned long long)rm->m_ack_seq);
	}

	if (hdr_off < sizeof(struct rds_header)) {
		/* see rds_tcp_write_space() */
		set_bit(SOCK_NOSPACE, &tc->t_sock->sk->sk_socket->flags);

		ret = rds_tcp_sendmsg(tc->t_sock,
				      (void *)&rm->m_inc.i_hdr + hdr_off,
				      sizeof(rm->m_inc.i_hdr) - hdr_off);
		if (ret < 0)
			goto out;
		done += ret;
		if (hdr_off + done != sizeof(struct rds_header))
			goto out;
	}

	more = rm->data.op_nents > 1 ? (MSG_MORE | MSG_SENDPAGE_NOTLAST) : 0;
	while (sg < rm->data.op_nents) {
		int flags = MSG_DONTWAIT | MSG_NOSIGNAL | more;

		ret = tc->t_sock->ops->sendpage(tc->t_sock,
						sg_page(&rm->data.op_sg[sg]),
						rm->data.op_sg[sg].offset + off,
						rm->data.op_sg[sg].length - off,
						flags);
		rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->data.op_sg[sg]),
			 rm->data.op_sg[sg].offset + off, rm->data.op_sg[sg].length - off,
			 ret);
		if (ret <= 0)
			break;

		off += ret;
		done += ret;
		if (off == rm->data.op_sg[sg].length) {
			off = 0;
			sg++;
		}
		if (sg == rm->data.op_nents - 1)
			more = 0;
	}

out:
	if (ret <= 0) {
		/* write_space will hit after EAGAIN, all else fatal */
		if (ret == -EAGAIN) {
			rds_tcp_stats_inc(s_tcp_sndbuf_full);
			ret = 0;
		} else {
			/* No need to disconnect/reconnect if path_drop
			 * has already been triggered, because, e.g., of
			 * an incoming RST.
			 */
			if (rds_conn_path_up(cp)) {
				pr_warn("RDS/tcp: send to %pI4 on cp [%d]"
					"returned %d, "
					"disconnecting and reconnecting\n",
					&conn->c_faddr, cp->cp_index, ret);
				rds_conn_path_drop(cp);
			}
		}
	}
	if (done == 0)
		done = ret;
	return done;
}

/*
 * rm->m_ack_seq is set to the tcp sequence number that corresponds to the
 * last byte of the message, including the header.  This means that the
 * entire message has been received if rm->m_ack_seq is "before" the next
 * unacked byte of the TCP sequence space.  We have to do very careful
 * wrapping 32bit comparisons here.
 */
static int rds_tcp_is_acked(struct rds_message *rm, uint64_t ack)
{
	if (!test_bit(RDS_MSG_HAS_ACK_SEQ, &rm->m_flags))
		return 0;
	return (__s32)((u32)rm->m_ack_seq - (u32)ack) < 0;
}

void rds_tcp_write_space(struct sock *sk)
{
	void (*write_space)(struct sock *sk);
	struct rds_conn_path *cp;
	struct rds_tcp_connection *tc;

	read_lock_bh(&sk->sk_callback_lock);
	cp = sk->sk_user_data;
	if (!cp) {
		write_space = sk->sk_write_space;
		goto out;
	}

	tc = cp->cp_transport_data;
	rdsdebug("write_space for tc %p\n", tc);
	write_space = tc->t_orig_write_space;
	rds_tcp_stats_inc(s_tcp_write_space_calls);

	rdsdebug("tcp una %u\n", rds_tcp_snd_una(tc));
	tc->t_last_seen_una = rds_tcp_snd_una(tc);
	rds_send_path_drop_acked(cp, rds_tcp_snd_una(tc), rds_tcp_is_acked);

	if ((atomic_read(&sk->sk_wmem_alloc) << 1) <= sk->sk_sndbuf)
		queue_delayed_work(rds_wq, &cp->cp_send_w, 0);

out:
	read_unlock_bh(&sk->sk_callback_lock);

	/*
	 * write_space is only called when data leaves tcp's send queue if
	 * SOCK_NOSPACE is set.  We set SOCK_NOSPACE every time we put
	 * data in tcp's send queue because we use write_space to parse the
	 * sequence numbers and notice that rds messages have been fully
	 * received.
	 *
	 * tcp's write_space clears SOCK_NOSPACE if the send queue has more
	 * than a certain amount of space. So we need to set it again *after*
	 * we call tcp's write_space or else we might only get called on the
	 * first of a series of incoming tcp acks.
	 */
	write_space(sk);

	if (sk->sk_socket)
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
}