Merge branch 'tipc-refactor-socket-receive-functions'
Jon Maloy says:
====================
tipc: refactor socket receive functions
We try to make the functions tipc_sk_recvmsg() and
tipc_sk_recvstream() more readable.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 8a4e9fe..7e45ef9 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.
@@ -1298,95 +1299,85 @@ 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)) {
- 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)
+ do {
+ /* Look at first msg in receive queue; wait if necessary */
+ rc = tipc_wait_for_rcvmsg(sock, &timeout);
+ if (unlikely(rc))
goto exit;
- res = sz;
- } else {
- if (is_connectionless || err == TIPC_CONN_SHUTDOWN ||
- m->msg_control)
- res = 0;
- else
- res = -ECONNRESET;
- }
+ 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);
+ } 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))
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;
}
/**
- * tipc_recv_stream - receive stream-oriented data
+ * tipc_recvstream - receive stream-oriented data
* @m: descriptor for message info
- * @buf_len: total size of user buffer area
+ * @buflen: total size of user buffer area
* @flags: receive flags
*
* Used for SOCK_STREAM messages only. If not enough data is available
@@ -1394,111 +1385,98 @@ static int tipc_recvmsg(struct socket *sock, struct msghdr *m, size_t buf_len,
*
* Returns size of returned message data, errno otherwise
*/
-static int tipc_recv_stream(struct socket *sock, struct msghdr *m,
- size_t buf_len, int flags)
+static int tipc_recvstream(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;
- long timeo;
- unsigned int sz;
- int target;
- int sz_copied = 0;
- u32 err;
- int res = 0, hlen;
+ struct sk_buff *skb;
+ struct tipc_msg *hdr;
+ struct tipc_skb_cb *skb_cb;
+ bool peek = flags & MSG_PEEK;
+ int offset, required, copy, copied = 0;
+ int hlen, dlen, err, rc;
+ long timeout;
/* Catch invalid receive attempts */
- if (unlikely(!buf_len))
+ if (unlikely(!buflen))
return -EINVAL;
lock_sock(sk);
if (unlikely(sk->sk_state == TIPC_OPEN)) {
- res = -ENOTCONN;
+ rc = -ENOTCONN;
goto exit;
}
+ required = sock_rcvlowat(sk, flags & MSG_WAITALL, buflen);
+ timeout = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
- target = sock_rcvlowat(sk, flags & MSG_WAITALL, buf_len);
- timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
+ do {
+ /* Look at first msg in receive queue; wait if necessary */
+ rc = tipc_wait_for_rcvmsg(sock, &timeout);
+ if (unlikely(rc))
+ break;
+ skb = skb_peek(&sk->sk_receive_queue);
+ skb_cb = TIPC_SKB_CB(skb);
+ hdr = buf_msg(skb);
+ dlen = msg_data_sz(hdr);
+ hlen = msg_hdr_sz(hdr);
+ err = msg_errcode(hdr);
-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)) {
- tsk_advance_rx_queue(sk);
- goto restart;
- }
-
- /* Optionally capture sender's address & ancillary data of first msg */
- if (sz_copied == 0) {
- set_orig_addr(m, msg);
- res = tipc_sk_anc_data_recv(m, msg, tsk);
- if (res)
- goto exit;
- }
-
- /* Capture message data (if valid) & compute return value (always) */
- if (!err) {
- u32 offset = TIPC_SKB_CB(buf)->bytes_read;
- u32 needed;
- int sz_to_copy;
-
- sz -= offset;
- needed = (buf_len - sz_copied);
- sz_to_copy = min(sz, needed);
-
- res = skb_copy_datagram_msg(buf, hlen + offset, m, sz_to_copy);
- if (res)
- goto exit;
-
- sz_copied += sz_to_copy;
-
- if (sz_to_copy < sz) {
- if (!(flags & MSG_PEEK))
- TIPC_SKB_CB(buf)->bytes_read =
- offset + sz_to_copy;
- goto exit;
+ /* Discard any empty non-errored (SYN-) message */
+ if (unlikely(!dlen && !err)) {
+ tsk_advance_rx_queue(sk);
+ continue;
}
- } else {
- if (sz_copied != 0)
- goto exit; /* can't add error msg to valid data */
- if ((err == TIPC_CONN_SHUTDOWN) || m->msg_control)
- res = 0;
- else
- res = -ECONNRESET;
- }
+ /* Collect msg meta data, incl. error code and rejected data */
+ if (!copied) {
+ set_orig_addr(m, hdr);
+ rc = tipc_sk_anc_data_recv(m, hdr, tsk);
+ if (rc)
+ break;
+ }
- if (unlikely(flags & MSG_PEEK))
- goto exit;
+ /* Copy data if msg ok, otherwise return error/partial data */
+ if (likely(!err)) {
+ offset = skb_cb->bytes_read;
+ copy = min_t(int, dlen - offset, buflen - copied);
+ rc = skb_copy_datagram_msg(skb, hlen + offset, m, copy);
+ if (unlikely(rc))
+ break;
+ copied += copy;
+ offset += copy;
+ if (unlikely(offset < dlen)) {
+ if (!peek)
+ skb_cb->bytes_read = offset;
+ break;
+ }
+ } else {
+ rc = 0;
+ if ((err != TIPC_CONN_SHUTDOWN) && !m->msg_control)
+ rc = -ECONNRESET;
+ if (copied || rc)
+ break;
+ }
- tsk->rcv_unacked += tsk_inc(tsk, hlen + msg_data_sz(msg));
- if (unlikely(tsk->rcv_unacked >= (tsk->rcv_win / 4)))
- tipc_sk_send_ack(tsk);
- tsk_advance_rx_queue(sk);
+ if (unlikely(peek))
+ break;
- /* Loop around if more data is required */
- if ((sz_copied < buf_len) && /* didn't get all requested data */
- (!skb_queue_empty(&sk->sk_receive_queue) ||
- (sz_copied < target)) && /* and more is ready or required */
- (!err)) /* and haven't reached a FIN */
- goto restart;
+ tsk_advance_rx_queue(sk);
+ /* Send connection flow control advertisement when applicable */
+ tsk->rcv_unacked += tsk_inc(tsk, hlen + dlen);
+ if (unlikely(tsk->rcv_unacked >= tsk->rcv_win / TIPC_ACK_RATE))
+ tipc_sk_send_ack(tsk);
+
+ /* Exit if all requested data or FIN/error received */
+ if (copied == buflen || err)
+ break;
+
+ } while (!skb_queue_empty(&sk->sk_receive_queue) || copied < required);
exit:
release_sock(sk);
- return sz_copied ? sz_copied : res;
+ return copied ? copied : rc;
}
/**
@@ -2593,7 +2571,7 @@ static const struct proto_ops stream_ops = {
.setsockopt = tipc_setsockopt,
.getsockopt = tipc_getsockopt,
.sendmsg = tipc_sendstream,
- .recvmsg = tipc_recv_stream,
+ .recvmsg = tipc_recvstream,
.mmap = sock_no_mmap,
.sendpage = sock_no_sendpage
};