tcp: replace cnt & rtt with struct in pkts_acked()

Replace 2 arguments (cnt and rtt) in the congestion control modules'
pkts_acked() function with a struct. This will allow adding more
information without having to modify existing congestion control
modules (tcp_nv in particular needs bytes in flight when packet
was sent).

As proposed by Neal Cardwell in his comments to the tcp_nv patch.

Signed-off-by: Lawrence Brakmo <brakmo@fb.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 6 insertions, 1 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 4775a1bba7f7..c9ab561387c4 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -854,6 +854,11 @@ enum tcp_ca_ack_event_flags {
 
 union tcp_cc_info;
 
+struct ack_sample {
+        u32 pkts_acked;
+        s32 rtt_us;
+};
+
 struct tcp_congestion_ops {
         struct list_head        list;
         u32 key;
@@ -877,7 +882,7 @@ struct tcp_congestion_ops {
         /* new value of cwnd after loss (optional) */
         u32  (*undo_cwnd)(struct sock *sk);
         /* hook for packet ack accounting (optional) */
-        void (*pkts_acked)(struct sock *sk, u32 num_acked, s32 rtt_us);
+        void (*pkts_acked)(struct sock *sk, const struct ack_sample *sample);
         /* get info for inet_diag (optional) */
         size_t (*get_info)(struct sock *sk, u32 ext, int *attr,
                            union tcp_cc_info *info);