Merge branch 'master' into ip-forwarding

- Merges aleksej-paschenko's with HEAD
- Adds vfs2 support for ip_forward

1 files changed, 17 insertions, 0 deletions

diff --git a/pkg/amutex/amutex.go b/pkg/amutex/amutex.go
index 1c4fd1784..a078a31db 100644
--- a/pkg/amutex/amutex.go
+++ b/pkg/amutex/amutex.go
@@ -18,6 +18,8 @@ package amutex
 
 import (
 	"sync/atomic"
+
+	"gvisor.dev/gvisor/pkg/syserror"
 )
 
 // Sleeper must be implemented by users of the abortable mutex to allow for
@@ -53,6 +55,21 @@ func (NoopSleeper) SleepFinish(success bool) {}
 // Interrupted implements Sleeper.Interrupted.
 func (NoopSleeper) Interrupted() bool { return false }
 
+// Block blocks until either receiving from ch succeeds (in which case it
+// returns nil) or sleeper is interrupted (in which case it returns
+// syserror.ErrInterrupted).
+func Block(sleeper Sleeper, ch <-chan struct{}) error {
+	cancel := sleeper.SleepStart()
+	select {
+	case <-ch:
+		sleeper.SleepFinish(true)
+		return nil
+	case <-cancel:
+		sleeper.SleepFinish(false)
+		return syserror.ErrInterrupted
+	}
+}
+
 // AbortableMutex is an abortable mutex. It allows Lock() to be aborted while it
 // waits to acquire the mutex.
 type AbortableMutex struct {