fixes #419 want to nni_aio_stop without blocking (#428)

* fixes #419 want to nni_aio_stop without blocking

This actually introduces an nni_aio_close() API that causes
nni_aio_begin to return NNG_ECLOSED, while scheduling a callback
on the AIO to do an NNG_ECLOSED as well.  This should be called
in non-blocking close() contexts instead of nni_aio_stop(), and
the cases where we call nni_aio_fini() multiple times are updated
updated to add nni_aio_stop() calls on all "interlinked" aios before
finalizing them.

Furthermore, we call nni_aio_close() as soon as practical in the
close path.  This closes an annoying race condition where the
callback from a lower subsystem could wind up rescheduling an
operation that we wanted to abort.

1 files changed, 15 insertions, 4 deletions

diff --git a/src/protocol/survey0/survey.c b/src/protocol/survey0/survey.c
index e725d2b3..51bce0c8 100644
--- a/src/protocol/survey0/survey.c
+++ b/src/protocol/survey0/survey.c
@@ -284,6 +284,16 @@ surv0_sock_close(void *arg)
 }
 
 static void
+surv0_pipe_stop(void *arg)
+{
+	surv0_pipe *p = arg;
+
+	nni_aio_stop(p->aio_getq);
+	nni_aio_stop(p->aio_send);
+	nni_aio_stop(p->aio_recv);
+}
+
+static void
 surv0_pipe_fini(void *arg)
 {
 	surv0_pipe *p = arg;
@@ -338,14 +348,14 @@ surv0_pipe_start(void *arg)
 }
 
 static void
-surv0_pipe_stop(void *arg)
+surv0_pipe_close(void *arg)
 {
 	surv0_pipe *p = arg;
 	surv0_sock *s = p->sock;
 
-	nni_aio_stop(p->aio_getq);
-	nni_aio_stop(p->aio_send);
-	nni_aio_stop(p->aio_recv);
+	nni_aio_close(p->aio_getq);
+	nni_aio_close(p->aio_send);
+	nni_aio_close(p->aio_recv);
 
 	nni_msgq_close(p->sendq);
 
@@ -532,6 +542,7 @@ static nni_proto_pipe_ops surv0_pipe_ops = {
 	.pipe_init  = surv0_pipe_init,
 	.pipe_fini  = surv0_pipe_fini,
 	.pipe_start = surv0_pipe_start,
+	.pipe_close = surv0_pipe_close,
 	.pipe_stop  = surv0_pipe_stop,
 };