From 946bba86cc9de9f7647e54b4980437e7b242aaf1 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Fri, 16 Feb 2024 13:56:10 +0100
Subject: [PATCH] Allow to cancel connect() operations when using io_uring

Motivation:

Whe using io_uring we can in fact cancel a connect() operation by just closing the underyling fd.

Modifications:

Don't mark the promise as uncancellable before issue the non-blocking connect() call
Add comment to explain code

Result:

Related to https://github.com/netty/netty/issues/13843 and https://github.com/netty/netty/pull/13849
---
 .../incubator/channel/uring/AbstractIOUringChannel.java     | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/transport-classes-io_uring/src/main/java/io/netty/incubator/channel/uring/AbstractIOUringChannel.java b/transport-classes-io_uring/src/main/java/io/netty/incubator/channel/uring/AbstractIOUringChannel.java
index 734d0b3f..da09d2b8 100644
--- a/transport-classes-io_uring/src/main/java/io/netty/incubator/channel/uring/AbstractIOUringChannel.java
+++ b/transport-classes-io_uring/src/main/java/io/netty/incubator/channel/uring/AbstractIOUringChannel.java
@@ -680,7 +680,9 @@ void connectComplete(int res) {
         @Override
         public void connect(
                 final SocketAddress remoteAddress, final SocketAddress localAddress, final ChannelPromise promise) {
-            if (!promise.setUncancellable() || !ensureOpen(promise)) {
+            // Don't mark the connect promise as uncancellable as in fact we can cancel it as it is using
+            // non-blocking io.
+            if (promise.isDone() || !ensureOpen(promise)) {
                 return;
             }
 
@@ -760,6 +762,8 @@ public void run() {
             promise.addListener(new ChannelFutureListener() {
                 @Override
                 public void operationComplete(ChannelFuture future) {
+                    // If the connect future is cancelled we also cancel the timeout and close the
+                    // underlying socket.
                     if (future.isCancelled()) {
                         cancelConnectTimeoutFuture();
                         connectPromise = null;