[TCP]: Cleanup tcp_tso_acked and tcp_clean_rtx_queue

Implements following cleanups:
- Comment re-placement (CodingStyle)
- tcp_tso_acked() local (wrapper-like) variable removal
  (readability)
- __-types removed (IMHO they make local variables jumpy looking
  and just was space)
- acked -> flag (naming conventions elsewhere in TCP code)
- linebreak adjustments (readability)
- nested if()s combined (reduced indentation)
- clarifying newlines added

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 4238ed9..8fe754b 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2525,55 +2525,49 @@ static void tcp_rearm_rto(struct sock *sk)
        }
 }
 
+/* If we get here, the whole TSO packet has not been acked. */
 static u32 tcp_tso_acked(struct sock *sk, struct sk_buff *skb)
 {
        struct tcp_sock *tp = tcp_sk(sk);
-       struct tcp_skb_cb *scb = TCP_SKB_CB(skb);
-       __u32 seq = tp->snd_una;
-       __u32 packets_acked;
+       u32 packets_acked;
 
-       /* If we get here, the whole TSO packet has not been
-        * acked.
-        */
-       BUG_ON(!after(scb->end_seq, seq));
+       BUG_ON(!after(TCP_SKB_CB(skb)->end_seq, tp->snd_una));
 
        packets_acked = tcp_skb_pcount(skb);
-       if (tcp_trim_head(sk, skb, seq - scb->seq))
+       if (tcp_trim_head(sk, skb, tp->snd_una - TCP_SKB_CB(skb)->seq))
                return 0;
        packets_acked -= tcp_skb_pcount(skb);
 
        if (packets_acked) {
                BUG_ON(tcp_skb_pcount(skb) == 0);
-               BUG_ON(!before(scb->seq, scb->end_seq));
+               BUG_ON(!before(TCP_SKB_CB(skb)->seq, TCP_SKB_CB(skb)->end_seq));
        }
 
        return packets_acked;
 }
 
-/* Remove acknowledged frames from the retransmission queue. */
-static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
+/* Remove acknowledged frames from the retransmission queue. If our packet
+ * is before the ack sequence we can discard it as it's confirmed to have
+ * arrived at the other end.
+ */
+static int tcp_clean_rtx_queue(struct sock *sk, s32 *seq_rtt_p)
 {
        struct tcp_sock *tp = tcp_sk(sk);
        const struct inet_connection_sock *icsk = inet_csk(sk);
        struct sk_buff *skb;
-       __u32 now = tcp_time_stamp;
+       u32 now = tcp_time_stamp;
        int fully_acked = 1;
-       int acked = 0;
+       int flag = 0;
        int prior_packets = tp->packets_out;
-       __s32 seq_rtt = -1;
+       s32 seq_rtt = -1;
        ktime_t last_ackt = net_invalid_timestamp();
 
-       while ((skb = tcp_write_queue_head(sk)) &&
-              skb != tcp_send_head(sk)) {
+       while ((skb = tcp_write_queue_head(sk)) && skb != tcp_send_head(sk)) {
                struct tcp_skb_cb *scb = TCP_SKB_CB(skb);
                u32 end_seq;
                u32 packets_acked;
-               __u8 sacked = scb->sacked;
+               u8 sacked = scb->sacked;
 
-               /* If our packet is before the ack sequence we can
-                * discard it as it's confirmed to have arrived at
-                * the other end.
-                */
                if (after(scb->end_seq, tp->snd_una)) {
                        if (tcp_skb_pcount(skb) == 1 ||
                            !after(tp->snd_una, scb->seq))
@@ -2598,38 +2592,38 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
                 * quickly.  This is severely frowned upon behavior.
                 */
                if (!(scb->flags & TCPCB_FLAG_SYN)) {
-                       acked |= FLAG_DATA_ACKED;
+                       flag |= FLAG_DATA_ACKED;
                } else {
-                       acked |= FLAG_SYN_ACKED;
+                       flag |= FLAG_SYN_ACKED;
                        tp->retrans_stamp = 0;
                }
 
                /* MTU probing checks */
-               if (fully_acked && icsk->icsk_mtup.probe_size) {
-                       if (!after(tp->mtu_probe.probe_seq_end, TCP_SKB_CB(skb)->end_seq)) {
-                               tcp_mtup_probe_success(sk, skb);
-                       }
+               if (fully_acked && icsk->icsk_mtup.probe_size &&
+                   !after(tp->mtu_probe.probe_seq_end, scb->end_seq)) {
+                       tcp_mtup_probe_success(sk, skb);
                }
 
                if (sacked) {
                        if (sacked & TCPCB_RETRANS) {
                                if (sacked & TCPCB_SACKED_RETRANS)
                                        tp->retrans_out -= packets_acked;
-                               acked |= FLAG_RETRANS_DATA_ACKED;
+                               flag |= FLAG_RETRANS_DATA_ACKED;
                                seq_rtt = -1;
                        } else if (seq_rtt < 0) {
                                seq_rtt = now - scb->when;
                                if (fully_acked)
                                        last_ackt = skb->tstamp;
                        }
+
                        if (sacked & TCPCB_SACKED_ACKED)
                                tp->sacked_out -= packets_acked;
                        if (sacked & TCPCB_LOST)
                                tp->lost_out -= packets_acked;
-                       if (sacked & TCPCB_URG) {
-                               if (tp->urg_mode && !before(end_seq, tp->snd_up))
-                                       tp->urg_mode = 0;
-                       }
+
+                       if ((sacked & TCPCB_URG) && tp->urg_mode &&
+                           !before(end_seq, tp->snd_up))
+                               tp->urg_mode = 0;
                } else if (seq_rtt < 0) {
                        seq_rtt = now - scb->when;
                        if (fully_acked)
@@ -2645,12 +2639,12 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
                tcp_clear_all_retrans_hints(tp);
        }
 
-       if (acked&FLAG_ACKED) {
+       if (flag & FLAG_ACKED) {
                u32 pkts_acked = prior_packets - tp->packets_out;
                const struct tcp_congestion_ops *ca_ops
                        = inet_csk(sk)->icsk_ca_ops;
 
-               tcp_ack_update_rtt(sk, acked, seq_rtt);
+               tcp_ack_update_rtt(sk, flag, seq_rtt);
                tcp_rearm_rto(sk);
 
                tp->fackets_out -= min(pkts_acked, tp->fackets_out);
@@ -2664,7 +2658,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
                        s32 rtt_us = -1;
 
                        /* Is the ACK triggering packet unambiguous? */
-                       if (!(acked & FLAG_RETRANS_DATA_ACKED)) {
+                       if (!(flag & FLAG_RETRANS_DATA_ACKED)) {
                                /* High resolution needed and available? */
                                if (ca_ops->flags & TCP_CONG_RTT_STAMP &&
                                    !ktime_equal(last_ackt,
@@ -2703,7 +2697,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, __s32 *seq_rtt_p)
        }
 #endif
        *seq_rtt_p = seq_rtt;
-       return acked;
+       return flag;
 }
 
 static void tcp_ack_probe(struct sock *sk)