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tipc: refactor function tipc_sk_recvmsg()

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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 2017-05-02 18:16:53 +02:00 committed by David S. Miller
parent b0e92279d3
commit e9f8b10101
1 changed files with 56 additions and 65 deletions
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121
net/tipc/socket.c
View file

@ -51,6 +51,7 @@
#define TIPC_FWD_MSG 1 #define TIPC_FWD_MSG 1
#define TIPC_MAX_PORT 0xffffffff #define TIPC_MAX_PORT 0xffffffff
#define TIPC_MIN_PORT 1 #define TIPC_MIN_PORT 1
#define TIPC_ACK_RATE 4 /* ACK at 1/4 of of rcv window size */
enum { enum {
TIPC_LISTEN = TCP_LISTEN, 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 * tipc_recvmsg - receive packet-oriented message
* @m: descriptor for message info * @m: descriptor for message info
* @buf_len: total size of user buffer area * @buflen: length of user buffer area
* @flags: receive flags * @flags: receive flags
* *
* Used for SOCK_DGRAM, SOCK_RDM, and SOCK_SEQPACKET messages. * 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 * Returns size of returned message data, errno otherwise
*/ */
static int tipc_recvmsg(struct socket *sock, struct msghdr *m, size_t buf_len, static int tipc_recvmsg(struct socket *sock, struct msghdr *m,
int flags) size_t buflen, int flags)
{ {
struct sock *sk = sock->sk; struct sock *sk = sock->sk;
struct tipc_sock *tsk = tipc_sk(sk); struct tipc_sock *tsk = tipc_sk(sk);
struct sk_buff *buf; struct sk_buff *skb;
struct tipc_msg *msg; struct tipc_msg *hdr;
bool is_connectionless = tipc_sk_type_connectionless(sk); bool connected = !tipc_sk_type_connectionless(sk);
long timeo; int rc, err, hlen, dlen, copy;
unsigned int sz; long timeout;
u32 err;
int res, hlen;
/* Catch invalid receive requests */ /* Catch invalid receive requests */
if (unlikely(!buf_len)) if (unlikely(!buflen))
return -EINVAL; return -EINVAL;
lock_sock(sk); lock_sock(sk);
if (unlikely(connected && sk->sk_state == TIPC_OPEN)) {
if (!is_connectionless && unlikely(sk->sk_state == TIPC_OPEN)) { rc = -ENOTCONN;
res = -ENOTCONN;
goto exit; goto exit;
} }
timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); do {
restart: /* Look at first msg in receive queue; wait if necessary */
rc = tipc_wait_for_rcvmsg(sock, &timeout);
/* Look for a message in receive queue; wait if necessary */ if (unlikely(rc))
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)) {
tsk_advance_rx_queue(sk);
goto restart;
}
/* 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)
goto exit;
/* Capture message data (if valid) & compute return value (always) */
if (!err) {
if (unlikely(buf_len < sz)) {
sz = buf_len;
m->msg_flags |= MSG_TRUNC;
}
res = skb_copy_datagram_msg(buf, hlen, m, sz);
if (res)
goto exit; goto exit;
res = sz; skb = skb_peek(&sk->sk_receive_queue);
} else { hdr = buf_msg(skb);
if (is_connectionless || err == TIPC_CONN_SHUTDOWN || dlen = msg_data_sz(hdr);
m->msg_control) hlen = msg_hdr_sz(hdr);
res = 0; err = msg_errcode(hdr);
else if (likely(dlen || err))
res = -ECONNRESET; break;
} tsk_advance_rx_queue(sk);
} while (1);
/* 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 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;
rc = skb_copy_datagram_msg(skb, hlen, m, copy);
} else {
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)) if (unlikely(flags & MSG_PEEK))
goto exit; 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); 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: exit:
release_sock(sk); release_sock(sk);
return res; return rc ? rc : copy;
} }
/** /**