On 04/29/2017 02:49 AM, Jon Maloy wrote:
> We try to make this function more readable by improving variable names
> and comments, plus some minor changes to the logics.
>
> Signed-off-by: Jon Maloy <[email protected]>
> ---
> net/tipc/socket.c | 109
> +++++++++++++++++++++++++-----------------------------
> 1 file changed, 50 insertions(+), 59 deletions(-)
>
> diff --git a/net/tipc/socket.c b/net/tipc/socket.c
> index 826bdad..9621630 100644
> --- a/net/tipc/socket.c
> +++ b/net/tipc/socket.c
> @@ -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,
> @@ -1305,7 +1306,7 @@ 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.
> @@ -1313,89 +1314,79 @@ 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);
We can rename connected to seqpacket by checking for that socket type as
thats the one using connection oriented recvmsg.
Reviewed-by: Parthasarathy Bhuvaragan
<[email protected]>
/Partha
> + 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)
> - 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)) {
> + do {
> + /* Look at first msg in receive queue; wait if necessary */
> + rc = tipc_wait_for_rcvmsg(sock, &timeout);
> + if (unlikely(rc))
> + goto exit;
> + 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;
> }
>
> /**
>
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
tipc-discussion mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/tipc-discussion
