Struct frontendFD

pkg/sentry/devices/nvproxy/frontend.go:93–132

frontendFD implements vfs.FileDescriptionImpl for /dev/nvidia# and dev/nvidiactl. +stateify savable

//
// +stateify savable
type frontendFD struct {
	vfsfd vfs.FileDescription
	vfs.FileDescriptionDefaultImpl
	vfs.DentryMetadataFileDescriptionImpl
	vfs.NoLockFD
	memmap.MappableNoTrackMappings

	dev           *frontendDevice
	containerName string
	hostFD        int32
	memmapFile    frontendFDMemmapFile

	// The driver's implementation of poll() for these files,
	// kernel-open/nvidia/nv.c:nvidia_poll(), unsets
	// nv_linux_file_private_t::dataless_event_pending if it's set. This makes
	// notifications from dataless_event_pending edge-triggered; a host poll()
	// or epoll_wait() that returns the notification consumes it, preventing
	// future calls to poll() or epoll_wait() from observing the same
	// notification again.
	//
	// This is problematic in gVisor: fdnotifier, which epoll_wait()s on an
	// epoll instance that includes our hostFD, will forward notifications to
	// registered waiters, but this typically only wakes up blocked task
	// goroutines which will later call vfs.FileDescription.Readiness() to get
	// the FD's most up-to-date state. If our implementation of Readiness()
	// just polls the underlying host FD, it will no longer observe the
	// consumed notification.
	//
	// To work around this, intercept all events from fdnotifier and cache them
	// for the first following call to Readiness(), essentially replicating the
	// driver's behavior.
	internalQueue waiter.Queue
	internalEntry waiter.Entry
	cachedEvents  atomicbitops.Uint64
	appQueue      waiter.Queue

	// clients are handles of clients owned by this frontendFD. clients is
	// protected by dev.nvp.clientsMu.
	clients map[*rootClient]struct{}
}

// Release implements vfs.FileDescriptionImpl.Release.
func (fd *frontendFD) Release(ctx context.Context) {