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: Parthasarathy Bhuvaragan <parthasarathy.bhuvaragan@ericsson.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jon Paul Maloy
David S. Miller
parent
b0e92279d3
commit
e9f8b10101
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@ -51,6 +51,7 @@
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#define TIPC_FWD_MSG 1
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#define TIPC_MAX_PORT 0xffffffff
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#define TIPC_MIN_PORT 1
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#define TIPC_ACK_RATE 4 /* ACK at 1/4 of of rcv window size */
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enum {
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TIPC_LISTEN = TCP_LISTEN,
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@ -1290,7 +1291,7 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)
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/**
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* tipc_recvmsg - receive packet-oriented message
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* @m: descriptor for message info
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* @buf_len: total size of user buffer area
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* @buflen: length of user buffer area
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* @flags: receive flags
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*
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* Used for SOCK_DGRAM, SOCK_RDM, and SOCK_SEQPACKET messages.
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@ -1298,89 +1299,79 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long *timeop)
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*
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* Returns size of returned message data, errno otherwise
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*/
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static int tipc_recvmsg(struct socket *sock, struct msghdr *m, size_t buf_len,
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int flags)
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static int tipc_recvmsg(struct socket *sock, struct msghdr *m,
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size_t buflen, int flags)
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{
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struct sock *sk = sock->sk;
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struct tipc_sock *tsk = tipc_sk(sk);
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struct sk_buff *buf;
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struct tipc_msg *msg;
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bool is_connectionless = tipc_sk_type_connectionless(sk);
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long timeo;
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unsigned int sz;
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u32 err;
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int res, hlen;
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struct sk_buff *skb;
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struct tipc_msg *hdr;
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bool connected = !tipc_sk_type_connectionless(sk);
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int rc, err, hlen, dlen, copy;
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long timeout;
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/* Catch invalid receive requests */
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if (unlikely(!buf_len))
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if (unlikely(!buflen))
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return -EINVAL;
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lock_sock(sk);
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if (!is_connectionless && unlikely(sk->sk_state == TIPC_OPEN)) {
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res = -ENOTCONN;
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if (unlikely(connected && sk->sk_state == TIPC_OPEN)) {
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rc = -ENOTCONN;
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goto exit;
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}
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timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
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timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
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restart:
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/* Look for a message in receive queue; wait if necessary */
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res = tipc_wait_for_rcvmsg(sock, &timeo);
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if (res)
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goto exit;
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/* Look at first message in receive queue */
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buf = skb_peek(&sk->sk_receive_queue);
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msg = buf_msg(buf);
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sz = msg_data_sz(msg);
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hlen = msg_hdr_sz(msg);
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err = msg_errcode(msg);
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/* Discard an empty non-errored message & try again */
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if ((!sz) && (!err)) {
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tsk_advance_rx_queue(sk);
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goto restart;
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}
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/* Capture sender's address (optional) */
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set_orig_addr(m, msg);
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/* Capture ancillary data (optional) */
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res = tipc_sk_anc_data_recv(m, msg, tsk);
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if (res)
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goto exit;
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/* Capture message data (if valid) & compute return value (always) */
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if (!err) {
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if (unlikely(buf_len < sz)) {
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sz = buf_len;
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m->msg_flags |= MSG_TRUNC;
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}
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res = skb_copy_datagram_msg(buf, hlen, m, sz);
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if (res)
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do {
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/* Look at first msg in receive queue; wait if necessary */
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rc = tipc_wait_for_rcvmsg(sock, &timeout);
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if (unlikely(rc))
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goto exit;
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res = sz;
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} else {
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if (is_connectionless || err == TIPC_CONN_SHUTDOWN ||
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m->msg_control)
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res = 0;
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else
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res = -ECONNRESET;
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}
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skb = skb_peek(&sk->sk_receive_queue);
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hdr = buf_msg(skb);
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dlen = msg_data_sz(hdr);
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hlen = msg_hdr_sz(hdr);
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err = msg_errcode(hdr);
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if (likely(dlen || err))
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break;
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tsk_advance_rx_queue(sk);
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} while (1);
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/* Collect msg meta data, including error code and rejected data */
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set_orig_addr(m, hdr);
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rc = tipc_sk_anc_data_recv(m, hdr, tsk);
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if (unlikely(rc))
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goto exit;
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/* Capture data if non-error msg, otherwise just set return value */
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if (likely(!err)) {
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copy = min_t(int, dlen, buflen);
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if (unlikely(copy != dlen))
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m->msg_flags |= MSG_TRUNC;
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rc = skb_copy_datagram_msg(skb, hlen, m, copy);
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} else {
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copy = 0;
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rc = 0;
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if (err != TIPC_CONN_SHUTDOWN && connected && !m->msg_control)
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rc = -ECONNRESET;
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}
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if (unlikely(rc))
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goto exit;
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/* Caption of data or error code/rejected data was successful */
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if (unlikely(flags & MSG_PEEK))
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goto exit;
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if (likely(!is_connectionless)) {
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tsk->rcv_unacked += tsk_inc(tsk, hlen + sz);
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if (unlikely(tsk->rcv_unacked >= (tsk->rcv_win / 4)))
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tipc_sk_send_ack(tsk);
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}
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tsk_advance_rx_queue(sk);
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if (likely(!connected))
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goto exit;
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/* Send connection flow control ack when applicable */
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tsk->rcv_unacked += tsk_inc(tsk, hlen + dlen);
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if (tsk->rcv_unacked >= tsk->rcv_win / TIPC_ACK_RATE)
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tipc_sk_send_ack(tsk);
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exit:
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release_sock(sk);
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return res;
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return rc ? rc : copy;
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}
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/**
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