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, 13 insertions, 3 deletions

diff --git a/src/protocol/pipeline0/pull.c b/src/protocol/pipeline0/pull.c
index c5017d50..81f6c137 100644
--- a/src/protocol/pipeline0/pull.c
+++ b/src/protocol/pipeline0/pull.c
@@ -68,6 +68,15 @@ pull0_sock_fini(void *arg)
 }
 
 static void
+pull0_pipe_stop(void *arg)
+{
+	pull0_pipe *p = arg;
+
+	nni_aio_stop(p->putq_aio);
+	nni_aio_stop(p->recv_aio);
+}
+
+static void
 pull0_pipe_fini(void *arg)
 {
 	pull0_pipe *p = arg;
@@ -110,12 +119,12 @@ pull0_pipe_start(void *arg)
 }
 
 static void
-pull0_pipe_stop(void *arg)
+pull0_pipe_close(void *arg)
 {
 	pull0_pipe *p = arg;
 
-	nni_aio_stop(p->putq_aio);
-	nni_aio_stop(p->recv_aio);
+	nni_aio_close(p->putq_aio);
+	nni_aio_close(p->recv_aio);
 }
 
 static void
@@ -198,6 +207,7 @@ static nni_proto_pipe_ops pull0_pipe_ops = {
 	.pipe_init  = pull0_pipe_init,
 	.pipe_fini  = pull0_pipe_fini,
 	.pipe_start = pull0_pipe_start,
+	.pipe_close = pull0_pipe_close,
 	.pipe_stop  = pull0_pipe_stop,
 };