Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 61 insertions, 0 deletions

diff --git a/src/runtime/netpoll_stub.go b/src/runtime/netpoll_stub.go
new file mode 100644
index 0000000..14cf0c3
--- /dev/null
+++ b/src/runtime/netpoll_stub.go
@@ -0,0 +1,61 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build plan9
+
+package runtime
+
+import "runtime/internal/atomic"
+
+var netpollInited atomic.Uint32
+var netpollWaiters atomic.Uint32
+
+var netpollStubLock mutex
+var netpollNote note
+
+// netpollBroken, protected by netpollBrokenLock, avoids a double notewakeup.
+var netpollBrokenLock mutex
+var netpollBroken bool
+
+func netpollGenericInit() {
+	netpollInited.Store(1)
+}
+
+func netpollBreak() {
+	lock(&netpollBrokenLock)
+	broken := netpollBroken
+	netpollBroken = true
+	if !broken {
+		notewakeup(&netpollNote)
+	}
+	unlock(&netpollBrokenLock)
+}
+
+// Polls for ready network connections.
+// Returns list of goroutines that become runnable.
+func netpoll(delay int64) gList {
+	// Implementation for platforms that do not support
+	// integrated network poller.
+	if delay != 0 {
+		// This lock ensures that only one goroutine tries to use
+		// the note. It should normally be completely uncontended.
+		lock(&netpollStubLock)
+
+		lock(&netpollBrokenLock)
+		noteclear(&netpollNote)
+		netpollBroken = false
+		unlock(&netpollBrokenLock)
+
+		notetsleep(&netpollNote, delay)
+		unlock(&netpollStubLock)
+		// Guard against starvation in case the lock is contended
+		// (eg when running TestNetpollBreak).
+		osyield()
+	}
+	return gList{}
+}
+
+func netpollinited() bool {
+	return netpollInited.Load() != 0
+}