dccp: Lockless integration of CCID congestion-control plugins

Based on Arnaldo's earlier patch, this patch integrates the standardised
CCID congestion control plugins (CCID-2 and CCID-3) of DCCP with dccp.ko:

 * enables a faster connection path by eliminating the need to always go 
   through the CCID registration lock;

 * updates the implementation to use only a single array whose size equals
   the number of configured CCIDs instead of the maximum (256);

 * since the CCIDs are now fixed array elements, synchronization is no
   longer needed, simplifying use and implementation.

CCID-2 is suggested as minimum for a basic DCCP implementation (RFC 4340, 10);
CCID-3 is a standards-track CCID supported by RFC 4342 and RFC 5348.

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

1 files changed, 0 insertions, 2 deletions

diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h
index 0bc4c9a02e19..f2230fc168e1 100644
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -432,10 +432,8 @@ static inline int dccp_ack_pending(const struct sock *sk)
 {
         const struct dccp_sock *dp = dccp_sk(sk);
         return dp->dccps_timestamp_echo != 0 ||
-#ifdef CONFIG_IP_DCCP_ACKVEC
                (dp->dccps_hc_rx_ackvec != NULL &&
                 dccp_ackvec_pending(dp->dccps_hc_rx_ackvec)) ||
-#endif
                inet_csk_ack_scheduled(sk);
 }