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, 14 insertions, 4 deletions

diff --git a/src/protocol/survey0/respond.c b/src/protocol/survey0/respond.c
index e553f6ce..7738a8b7 100644
--- a/src/protocol/survey0/respond.c
+++ b/src/protocol/survey0/respond.c
@@ -290,6 +290,15 @@ resp0_sock_close(void *arg)
 }
 
 static void
+resp0_pipe_stop(void *arg)
+{
+	resp0_pipe *p = arg;
+
+	nni_aio_stop(p->aio_send);
+	nni_aio_stop(p->aio_recv);
+}
+
+static void
 resp0_pipe_fini(void *arg)
 {
 	resp0_pipe *p = arg;
@@ -344,12 +353,15 @@ resp0_pipe_start(void *arg)
 }
 
 static void
-resp0_pipe_stop(void *arg)
+resp0_pipe_close(void *arg)
 {
 	resp0_pipe *p = arg;
 	resp0_sock *s = p->psock;
 	resp0_ctx * ctx;
 
+	nni_aio_close(p->aio_send);
+	nni_aio_close(p->aio_recv);
+
 	nni_mtx_lock(&s->mtx);
 	while ((ctx = nni_list_first(&p->sendq)) != NULL) {
 		nni_aio *aio;
@@ -369,9 +381,6 @@ resp0_pipe_stop(void *arg)
 	}
 	nni_idhash_remove(s->pipes, p->id);
 	nni_mtx_unlock(&s->mtx);
-
-	nni_aio_stop(p->aio_send);
-	nni_aio_stop(p->aio_recv);
 }
 
 static void
@@ -626,6 +635,7 @@ static nni_proto_pipe_ops resp0_pipe_ops = {
 	.pipe_init  = resp0_pipe_init,
 	.pipe_fini  = resp0_pipe_fini,
 	.pipe_start = resp0_pipe_start,
+	.pipe_close = resp0_pipe_close,
 	.pipe_stop  = resp0_pipe_stop,
 };