From 1d033484ee1a2ec26d3eead073e7bc0f889ffdf4 Mon Sep 17 00:00:00 2001
From: Garrett D'Amore <garrett@damore.org>
Date: Tue, 15 May 2018 01:47:12 -0700
Subject: 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.
---
 src/supplemental/http/http_conn.c   | 40 +++++++++++++++++++++----------------
 src/supplemental/http/http_server.c | 16 +++++----------
 2 files changed, 28 insertions(+), 28 deletions(-)

(limited to 'src/supplemental/http')

diff --git a/src/supplemental/http/http_conn.c b/src/supplemental/http/http_conn.c
index f3b16370..15d1f776 100644
--- a/src/supplemental/http/http_conn.c
+++ b/src/supplemental/http/http_conn.c
@@ -110,22 +110,26 @@ http_close(nni_http_conn *conn)
 	}
 
 	conn->closed = true;
-	if (nni_list_first(&conn->wrq)) {
-		nni_aio_abort(conn->wr_aio, NNG_ECLOSED);
-		// Abort all operations except the one in flight.
-		while ((aio = nni_list_last(&conn->wrq)) !=
-		    nni_list_first(&conn->wrq)) {
-			nni_aio_list_remove(aio);
-			nni_aio_finish_error(aio, NNG_ECLOSED);
-		}
+	nni_aio_close(conn->wr_aio);
+	nni_aio_close(conn->rd_aio);
+
+	if ((aio = conn->rd_uaio) != NULL) {
+		conn->rd_uaio = NULL;
+		nni_aio_finish_error(aio, NNG_ECLOSED);
 	}
-	if (nni_list_first(&conn->rdq)) {
-		nni_aio_abort(conn->rd_aio, NNG_ECLOSED);
-		while ((aio = nni_list_last(&conn->rdq)) !=
-		    nni_list_first(&conn->rdq)) {
-			nni_aio_list_remove(aio);
-			nni_aio_finish_error(aio, NNG_ECLOSED);
-		}
+	if ((aio = conn->wr_uaio) != NULL) {
+		conn->wr_uaio = NULL;
+		nni_aio_finish_error(aio, NNG_ECLOSED);
+	}
+
+	// Abort all operations except the one in flight.
+	while ((aio = nni_list_first(&conn->wrq)) != NULL) {
+		nni_aio_list_remove(aio);
+		nni_aio_finish_error(aio, NNG_ECLOSED);
+	}
+	while ((aio = nni_list_first(&conn->rdq)) != NULL) {
+		nni_aio_list_remove(aio);
+		nni_aio_finish_error(aio, NNG_ECLOSED);
 	}
 
 	if (conn->sock != NULL) {
@@ -668,6 +672,9 @@ nni_http_tls_verified(nni_http_conn *conn)
 void
 nni_http_conn_fini(nni_http_conn *conn)
 {
+	nni_aio_stop(conn->wr_aio);
+	nni_aio_stop(conn->rd_aio);
+
 	nni_mtx_lock(&conn->mtx);
 	http_close(conn);
 	if ((conn->sock != NULL) && (conn->fini != NULL)) {
@@ -675,8 +682,7 @@ nni_http_conn_fini(nni_http_conn *conn)
 		conn->sock = NULL;
 	}
 	nni_mtx_unlock(&conn->mtx);
-	nni_aio_stop(conn->wr_aio);
-	nni_aio_stop(conn->rd_aio);
+
 	nni_aio_fini(conn->wr_aio);
 	nni_aio_fini(conn->rd_aio);
 	nni_free(conn->rd_buf, conn->rd_bufsz);
diff --git a/src/supplemental/http/http_server.c b/src/supplemental/http/http_server.c
index c92de586..c7738aee 100644
--- a/src/supplemental/http/http_server.c
+++ b/src/supplemental/http/http_server.c
@@ -228,12 +228,6 @@ http_sconn_reap(void *arg)
 	NNI_FREE_STRUCT(sc);
 }
 
-static void
-http_sconn_fini(http_sconn *sc)
-{
-	nni_reap(&sc->reap, http_sconn_reap, sc);
-}
-
 static void
 http_sconn_close_locked(http_sconn *sc)
 {
@@ -245,15 +239,15 @@ http_sconn_close_locked(http_sconn *sc)
 	NNI_ASSERT(!sc->finished);
 
 	sc->closed = true;
-	nni_aio_abort(sc->rxaio, NNG_ECLOSED);
-	nni_aio_abort(sc->txaio, NNG_ECLOSED);
-	nni_aio_abort(sc->txdataio, NNG_ECLOSED);
-	nni_aio_abort(sc->cbaio, NNG_ECLOSED);
+	nni_aio_close(sc->rxaio);
+	nni_aio_close(sc->txaio);
+	nni_aio_close(sc->txdataio);
+	nni_aio_close(sc->cbaio);
 
 	if ((conn = sc->conn) != NULL) {
 		nni_http_conn_close(conn);
 	}
-	http_sconn_fini(sc);
+	nni_reap(&sc->reap, http_sconn_reap, sc);
 }
 
 static void
-- 
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