s4-packet: make packet_recv_disable() a lot more efficient

this avoids doing an epoll system call when we want to prevent receipt
of packets on a socket, unless there actually is a packet to receive.

diff --git a/source4/lib/stream/packet.c b/source4/lib/stream/packet.c
index 251d951e707ff3c5ae7b09475859b8f2c90fdd85..98343707c12e441ca4d406f68b91932f8e0a71da 100644 (file)
--- a/source4/lib/stream/packet.c
+++ b/source4/lib/stream/packet.c
@@ -42,6 +42,7 @@ struct packet_context {
        bool serialise;
        int processing;
        bool recv_disable;
+       bool recv_need_enable;
        bool nofree;
 
        bool busy;
@@ -256,6 +257,7 @@ _PUBLIC_ void packet_recv(struct packet_context *pc)
        }
 
        if (pc->recv_disable) {
+               pc->recv_need_enable = true;
                EVENT_FD_NOT_READABLE(pc->fde);
                return;
        }
@@ -464,7 +466,6 @@ next_partial:
 */
 _PUBLIC_ void packet_recv_disable(struct packet_context *pc)
 {
-       EVENT_FD_NOT_READABLE(pc->fde);
        pc->recv_disable = true;
 }
 
@@ -473,7 +474,10 @@ _PUBLIC_ void packet_recv_disable(struct packet_context *pc)
 */
 _PUBLIC_ void packet_recv_enable(struct packet_context *pc)
 {
-       EVENT_FD_READABLE(pc->fde);
+       if (pc->recv_need_enable) {
+               pc->recv_need_enable = false;
+               EVENT_FD_READABLE(pc->fde);
+       }
        pc->recv_disable = false;
        if (pc->num_read != 0 && pc->packet_size >= pc->num_read) {
                event_add_timed(pc->ev, pc, timeval_zero(), packet_next_event, pc);