From 05d88970258537ca58aaf93c8594a3dc2ff6afbf Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Tue, 1 Sep 2020 10:57:06 +0200
Subject: [PATCH] Correctly handle POLLRDHUP registration in all cases

Motivation:

When accepting a Channel we did register it for POLLRDHUP, but unfortunally we used the IOUringSubmissionQueue that is tied to the IOUringEventLoop that is used for the ServerChannel. This is not correct as the EventLoop used for the accepted Channel may be different.

Modification:

Move logic into doRegister() and so register for POLLRDHUP on the right IOURingSubmissionQueue

Result:

Correct POLLRDHUP handling
---
 .../channel/uring/AbstractIOUringServerChannel.java   |  5 -----
 .../channel/uring/AbstractIOUringStreamChannel.java   | 11 +++++++++++
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/transport-native-io_uring/src/main/java/io/netty/channel/uring/AbstractIOUringServerChannel.java b/transport-native-io_uring/src/main/java/io/netty/channel/uring/AbstractIOUringServerChannel.java
index 8f746fc363..07b2a0f042 100644
--- a/transport-native-io_uring/src/main/java/io/netty/channel/uring/AbstractIOUringServerChannel.java
+++ b/transport-native-io_uring/src/main/java/io/netty/channel/uring/AbstractIOUringServerChannel.java
@@ -77,11 +77,6 @@ abstract class AbstractIOUringServerChannel extends AbstractIOUringChannel imple
                 allocHandle.incMessagesRead(1);
                 try {
                     Channel channel = newChildChannel(res);
-                    // Register accepted channel for POLLRDHUP
-                    IOUringSubmissionQueue submissionQueue = submissionQueue();
-                    submissionQueue.addPollRdHup(res);
-                    submissionQueue.submit();
-
                     pipeline.fireChannelRead(channel);
                     if (allocHandle.continueReading()) {
                         scheduleRead();
diff --git a/transport-native-io_uring/src/main/java/io/netty/channel/uring/AbstractIOUringStreamChannel.java b/transport-native-io_uring/src/main/java/io/netty/channel/uring/AbstractIOUringStreamChannel.java
index 3df12dd417..feb64c2f38 100644
--- a/transport-native-io_uring/src/main/java/io/netty/channel/uring/AbstractIOUringStreamChannel.java
+++ b/transport-native-io_uring/src/main/java/io/netty/channel/uring/AbstractIOUringStreamChannel.java
@@ -187,6 +187,17 @@ abstract class AbstractIOUringStreamChannel extends AbstractIOUringChannel imple
         }
     }
 
+    @Override
+    protected void doRegister() throws Exception {
+        super.doRegister();
+        if (active) {
+            // Register for POLLRDHUP if this channel is already considered active.
+            IOUringSubmissionQueue submissionQueue = submissionQueue();
+            submissionQueue.addPollRdHup(fd().intValue());
+            submissionQueue.submit();
+        }
+    }
+
     class IOUringStreamUnsafe extends AbstractUringUnsafe {
 
         // Overridden here just to be able to access this method from AbstractEpollStreamChannel