Add io_uring support

paper-server/build.gradle.kts

@@ -131,6 +131,9 @@ dependencies {
         isTransitive = false
     }
     implementation("io.netty:netty-codec-haproxy:4.2.7.Final") // Add support for proxy protocol
+    implementation("io.netty:netty-transport-classes-io_uring:4.2.7.Final") // Add support for io_uring
+    implementation("io.netty:netty-transport-native-io_uring:4.2.7.Final:linux-x86_64")
+    implementation("io.netty:netty-transport-native-io_uring:4.2.7.Final:linux-aarch_64")
     implementation("org.apache.logging.log4j:log4j-iostreams:2.25.2")
     implementation("org.ow2.asm:asm-commons:9.9.1")
     implementation("org.spongepowered:configurate-yaml:4.2.0")

paper-server/patches/sources/net/minecraft/network/Connection.java.patch

@@ -222,14 +222,21 @@
          }
 
          if (this.tickCount++ % 20 == 0) {
-@@ -390,6 +_,7 @@
+@@ -390,12 +_,13 @@
      }
 
      public void disconnect(final DisconnectionDetails details) {
 +        this.preparing = false; // Spigot
          if (this.channel == null) {
              this.delayedDisconnect = details;
          }
+
+         if (this.isConnected()) {
+-            this.channel.close().awaitUninterruptibly();
++            this.channel.close(); // We can't wait as this may be called from an event loop.
+             this.disconnectionDetails = details;
+         }
+     }
 @@ -534,6 +_,14 @@
          }
      }

paper-server/patches/sources/net/minecraft/server/network/EventLoopGroupHolder.java.patch

@@ -1,6 +1,6 @@
 --- a/net/minecraft/server/network/EventLoopGroupHolder.java
 +++ b/net/minecraft/server/network/EventLoopGroupHolder.java
-@@ -48,19 +_,39 @@
+@@ -48,19 +_,63 @@
              return LocalIoHandler.newFactory();
          }
      };
@@ -12,6 +12,20 @@
 +        }
 +    };
 +    // Paper end - Unix domain socket support
++    // Paper start - io_uring transport support
++    private static final EventLoopGroupHolder IO_URING = new EventLoopGroupHolder("IO Uring", io.netty.channel.uring.IoUringSocketChannel.class, io.netty.channel.uring.IoUringServerSocketChannel.class) {
++        @Override
++        protected IoHandlerFactory ioHandlerFactory() {
++            return io.netty.channel.uring.IoUringIoHandler.newFactory();
++        }
++    };
++    private static final EventLoopGroupHolder IO_URING_UNIX_DOMAIN = new EventLoopGroupHolder("Unix Domain Socket", io.netty.channel.uring.IoUringDomainSocketChannel.class, io.netty.channel.uring.IoUringServerDomainSocketChannel.class) {
++        @Override
++        protected IoHandlerFactory ioHandlerFactory() {
++            return io.netty.channel.uring.IoUringIoHandler.newFactory();
++        }
++    };
++    // Paper end - io_uring transport support
      private final String type;
      private final Class<? extends Channel> channelCls;
      private final Class<? extends ServerChannel> serverChannelCls;
@@ -29,6 +43,16 @@
                  return KQUEUE;
              }
 
++            // Paper start - io_uring transport support
++            if (io.papermc.paper.configuration.GlobalConfiguration.get().network.useIoUringTransport) {
++                if (address instanceof io.netty.channel.unix.DomainSocketAddress) {
++                    return IO_URING_UNIX_DOMAIN;
++                } else {
++                    return IO_URING;
++                }
++            }
++            // Paper end - io_uring transport support
++
              if (Epoll.isAvailable()) {
 -                return EPOLL;
 +                // Paper start - Unix domain socket support

paper-server/src/main/java/io/papermc/paper/configuration/GlobalConfiguration.java

@@ -141,6 +141,28 @@ public boolean isProxyOnlineMode() {
         }
     }
 
+    public Network network;
+
+    public class Network extends ConfigurationPart {
+        public boolean useIoUringTransport = false;
+
+        @PostProcess
+        private void postProcess() {
+            if (!this.useIoUringTransport) return;
+
+            if (!io.netty.channel.uring.IoUring.isAvailable()) {
+                LOGGER.error("Linux io_uring transport is enabled but is not supported on this system. Disabling io_uring...");
+                this.useIoUringTransport = false;
+            }
+
+            if (!net.minecraft.server.MinecraftServer.getServer().useNativeTransport()) {
+                LOGGER.error("Linux io_uring transport is enabled but native transports are disabled in server.properties. Disabling io_uring...");
+                this.useIoUringTransport = false;
+            }
+        }
+
+    }
+
     public Console console;
 
     public class Console extends ConfigurationPart {