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Commit e9f8b101 authored by Jon Paul Maloy's avatar Jon Paul Maloy Committed by David S. Miller
Browse files

tipc: refactor function tipc_sk_recvmsg() 



We try to make this function more readable by improving variable names
and comments, plus some minor changes to the logics.

Reviewed-by: default avatarParthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com>
Signed-off-by: default avatarJon Maloy <jon.maloy@ericsson.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b0e92279

net/tipc/socket.c

+50 −59
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ 
#define TIPC_FWD_MSG		1

#define TIPC_MAX_PORT		0xffffffff

#define TIPC_MIN_PORT		1

#define TIPC_ACK_RATE		4       /* ACK at 1/4 of of rcv window size */



enum {

	TIPC_LISTEN = TCP_LISTEN,
@@ -1290,7 +1291,7 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop) 
/**

 * tipc_recvmsg - receive packet-oriented message

 * @m: descriptor for message info

 * @buf_len: total size of user buffer area

 * @buflen: length of user buffer area

 * @flags: receive flags

 *

 * Used for SOCK_DGRAM, SOCK_RDM, and SOCK_SEQPACKET messages.
@@ -1298,89 +1299,79 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop) 
 *

 * Returns size of returned message data, errno otherwise

 */

static int tipc_recvmsg(struct socket *sock, struct msghdr *m, size_t buf_len,

			int flags)

static int tipc_recvmsg(struct socket *sock, struct msghdr *m,

			size_t buflen,	int flags)

{

	struct sock *sk = sock->sk;

	struct tipc_sock *tsk = tipc_sk(sk);

	struct sk_buff *buf;

	struct tipc_msg *msg;

	bool is_connectionless = tipc_sk_type_connectionless(sk);

	long timeo;

	unsigned int sz;

	u32 err;

	int res, hlen;

	struct sk_buff *skb;

	struct tipc_msg *hdr;

	bool connected = !tipc_sk_type_connectionless(sk);

	int rc, err, hlen, dlen, copy;

	long timeout;



	/* Catch invalid receive requests */

	if (unlikely(!buf_len))

	if (unlikely(!buflen))

		return -EINVAL;



	lock_sock(sk);



	if (!is_connectionless && unlikely(sk->sk_state == TIPC_OPEN)) {

		res = -ENOTCONN;

	if (unlikely(connected && sk->sk_state == TIPC_OPEN)) {

		rc = -ENOTCONN;

		goto exit;

	}

	timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);



	timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);

restart:



	/* Look for a message in receive queue; wait if necessary */

	res = tipc_wait_for_rcvmsg(sock, &timeo);

	if (res)

	do {

		/* Look at first msg in receive queue; wait if necessary */

		rc = tipc_wait_for_rcvmsg(sock, &timeout);

		if (unlikely(rc))

			goto exit;



	/* Look at first message in receive queue */

	buf = skb_peek(&sk->sk_receive_queue);

	msg = buf_msg(buf);

	sz = msg_data_sz(msg);

	hlen = msg_hdr_sz(msg);

	err = msg_errcode(msg);



	/* Discard an empty non-errored message & try again */

	if ((!sz) && (!err)) {

		skb = skb_peek(&sk->sk_receive_queue);

		hdr = buf_msg(skb);

		dlen = msg_data_sz(hdr);

		hlen = msg_hdr_sz(hdr);

		err = msg_errcode(hdr);

		if (likely(dlen || err))

			break;

		tsk_advance_rx_queue(sk);

		goto restart;

	}

	} while (1);



	/* Capture sender's address (optional) */

	set_orig_addr(m, msg);



	/* Capture ancillary data (optional) */

	res = tipc_sk_anc_data_recv(m, msg, tsk);

	if (res)

	/* Collect msg meta data, including error code and rejected data */

	set_orig_addr(m, hdr);

	rc = tipc_sk_anc_data_recv(m, hdr, tsk);

	if (unlikely(rc))

		goto exit;



	/* Capture message data (if valid) & compute return value (always) */

	if (!err) {

		if (unlikely(buf_len < sz)) {

			sz = buf_len;

	/* Capture data if non-error msg, otherwise just set return value */

	if (likely(!err)) {

		copy = min_t(int, dlen, buflen);

		if (unlikely(copy != dlen))

			m->msg_flags |= MSG_TRUNC;

		}

		res = skb_copy_datagram_msg(buf, hlen, m, sz);

		if (res)

			goto exit;

		res = sz;

		rc = skb_copy_datagram_msg(skb, hlen, m, copy);

	} else {

		if (is_connectionless || err == TIPC_CONN_SHUTDOWN ||

		    m->msg_control)

			res = 0;

		else

			res = -ECONNRESET;

		copy = 0;

		rc = 0;

		if (err != TIPC_CONN_SHUTDOWN && connected && !m->msg_control)

			rc = -ECONNRESET;

	}

	if (unlikely(rc))

		goto exit;



	/* Caption of data or error code/rejected data was successful */

	if (unlikely(flags & MSG_PEEK))

		goto exit;



	if (likely(!is_connectionless)) {

		tsk->rcv_unacked += tsk_inc(tsk, hlen + sz);

		if (unlikely(tsk->rcv_unacked >= (tsk->rcv_win / 4)))

			tipc_sk_send_ack(tsk);

	}

	tsk_advance_rx_queue(sk);

	if (likely(!connected))

		goto exit;



	/* Send connection flow control ack when applicable */

	tsk->rcv_unacked += tsk_inc(tsk, hlen + dlen);

	if (tsk->rcv_unacked >= tsk->rcv_win / TIPC_ACK_RATE)

		tipc_sk_send_ack(tsk);

exit:

	release_sock(sk);

	return res;

	return rc ? rc : copy;

}



/**