dccp ccid-2: Stop polling

This updates CCID-2 to use the CCID dequeuing mechanism, converting from
previous continuous-polling to a now event-driven mechanism.

Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 20 insertions, 8 deletions

diff --git a/net/dccp/ccids/ccid2.c b/net/dccp/ccids/ccid2.c
index d850e291f87c..6576eae9e779 100644
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
@@ -78,12 +78,9 @@ static int ccid2_hc_tx_alloc_seq(struct ccid2_hc_tx_sock *hc)
 
 static int ccid2_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
 {
-        struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
-
-        if (hc->tx_pipe < hc->tx_cwnd)
-                return 0;
-
-        return 1; /* XXX CCID should dequeue when ready instead of polling */
+        if (ccid2_cwnd_network_limited(ccid2_hc_tx_sk(sk)))
+                return CCID_PACKET_WILL_DEQUEUE_LATER;
+        return CCID_PACKET_SEND_AT_ONCE;
 }
 
 static void ccid2_change_l_ack_ratio(struct sock *sk, u32 val)
@@ -115,6 +112,7 @@ static void ccid2_hc_tx_rto_expire(unsigned long data)
 {
         struct sock *sk = (struct sock *)data;
         struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
+        const bool sender_was_blocked = ccid2_cwnd_network_limited(hc);
 
         bh_lock_sock(sk);
         if (sock_owned_by_user(sk)) {
@@ -129,8 +127,6 @@ static void ccid2_hc_tx_rto_expire(unsigned long data)
         if (hc->tx_rto > DCCP_RTO_MAX)
                 hc->tx_rto = DCCP_RTO_MAX;
 
-        sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
-
         /* adjust pipe, cwnd etc */
         hc->tx_ssthresh = hc->tx_cwnd / 2;
         if (hc->tx_ssthresh < 2)
@@ -146,6 +142,12 @@ static void ccid2_hc_tx_rto_expire(unsigned long data)
         hc->tx_rpseq    = 0;
         hc->tx_rpdupack = -1;
         ccid2_change_l_ack_ratio(sk, 1);
+
+        /* if we were blocked before, we may now send cwnd=1 packet */
+        if (sender_was_blocked)
+                tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet);
+        /* restart backed-off timer */
+        sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
 out:
         bh_unlock_sock(sk);
         sock_put(sk);
@@ -434,6 +436,7 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
 {
         struct dccp_sock *dp = dccp_sk(sk);
         struct ccid2_hc_tx_sock *hc = ccid2_hc_tx_sk(sk);
+        const bool sender_was_blocked = ccid2_cwnd_network_limited(hc);
         u64 ackno, seqno;
         struct ccid2_seq *seqp;
         unsigned char *vector;
@@ -631,6 +634,10 @@ static void ccid2_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
                 sk_stop_timer(sk, &hc->tx_rtotimer);
         else
                 sk_reset_timer(sk, &hc->tx_rtotimer, jiffies + hc->tx_rto);
+
+        /* check if incoming Acks allow pending packets to be sent */
+        if (sender_was_blocked && !ccid2_cwnd_network_limited(hc))
+                tasklet_schedule(&dccp_sk(sk)->dccps_xmitlet);
 }
 
 static int ccid2_hc_tx_init(struct ccid *ccid, struct sock *sk)
diff --git a/net/dccp/ccids/ccid2.h b/net/dccp/ccids/ccid2.h
index 9731c2dc1487..25cb6b216eda 100644
--- a/net/dccp/ccids/ccid2.h
+++ b/net/dccp/ccids/ccid2.h
@@ -81,6 +81,11 @@ struct ccid2_hc_tx_sock {
         u64                     tx_high_ack;
 };
 
+static inline bool ccid2_cwnd_network_limited(struct ccid2_hc_tx_sock *hc)
+{
+        return hc->tx_pipe >= hc->tx_cwnd;
+}
+
 struct ccid2_hc_rx_sock {
         int     rx_data;
 };