[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>

1 files changed, 30 insertions, 36 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 4238ed98acb9..8fe754be8076 100644
--- 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)