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Message-ID: <1493741814-25899-2-git-send-email-jon.maloy@ericsson.com>
Date: Tue, 2 May 2017 18:16:53 +0200
From: Jon Maloy <jon.maloy@...csson.com>
To: <davem@...emloft.net>, <netdev@...r.kernel.org>
CC: <parthasarathy.bhuvaragan@...csson.com>, <ying.xue@...driver.com>,
<tipc-discussion@...ts.sourceforge.net>
Subject: [net-next 1/2] 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@...csson.com>
Signed-off-by: Jon Maloy <jon.maloy@...csson.com>
---
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 8a4e9fe..3855bfd 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,
@@ -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)
- 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;
}
/**
--
2.1.4
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