rxrpc: Do lazy DF flag resetting

Don't reset the DF flag after transmission, but rather set it when needed
since it should be a fast op now that we call IP directly.

This includes turning it off for RESPONSE packets and, for the moment, ACK
packets.  In future, we will need to turn it on for ACK packets used to do
path MTU discovery.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: linux-afs@lists.infradead.org
cc: netdev@vger.kernel.org

diff --git a/net/rxrpc/output.c b/net/rxrpc/output.c
index 1e039b6..8aa8ba3 100644 (file)
--- a/net/rxrpc/output.c
+++ b/net/rxrpc/output.c
@@ -231,6 +231,7 @@ int rxrpc_send_ack_packet(struct rxrpc_call *call, struct rxrpc_txbuf *txb)
        txb->ack.previousPacket = htonl(call->rx_highest_seq);
 
        iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, len);
+       rxrpc_local_dont_fragment(conn->local, false);
        ret = do_udp_sendmsg(conn->local->socket, &msg, len);
        call->peer->last_tx_at = ktime_get_seconds();
        if (ret < 0) {
@@ -406,6 +407,7 @@ dont_set_request_ack:
         * think it's small enough */
        if (txb->len >= call->peer->maxdata)
                goto send_fragmentable;
+       rxrpc_local_dont_fragment(conn->local, true);
 
        txb->wire.flags = txb->flags & RXRPC_TXBUF_WIRE_FLAGS;
        txb->last_sent = ktime_get_real();
@@ -492,8 +494,6 @@ send_fragmentable:
                rxrpc_inc_stat(call->rxnet, stat_tx_data_send_frag);
                ret = do_udp_sendmsg(conn->local->socket, &msg, len);
                conn->peer->last_tx_at = ktime_get_seconds();
-
-               rxrpc_local_dont_fragment(conn->local, true);
                break;
 
        default:

diff --git a/net/rxrpc/rxkad.c b/net/rxrpc/rxkad.c
index 28c9ce7..e451ac9 100644 (file)
--- a/net/rxrpc/rxkad.c
+++ b/net/rxrpc/rxkad.c
@@ -726,7 +726,6 @@ static int rxkad_send_response(struct rxrpc_connection *conn,
 
        rxrpc_local_dont_fragment(conn->local, false);
        ret = kernel_sendmsg(conn->local->socket, &msg, iov, 3, len);
-       rxrpc_local_dont_fragment(conn->local, true);
        if (ret < 0) {
                trace_rxrpc_tx_fail(conn->debug_id, serial, ret,
                                    rxrpc_tx_point_rxkad_response);