Revert "daemon/command: add support for sd_notify "reload" notifications"

This reverts commit af18206630.

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

daemon/command/daemon.go

@@ -531,13 +531,6 @@ func (cli *daemonCLI) reloadConfig() {
 		}
 	}
 
-	// On Linux, we use sd_notify to indicate we're reloading config. We send
-	// this signal as early as possible to let systemd know we're reloading,
-	// but must signal "ready" after this completes (even on failure), which
-	// is done by the reload function defined above.
-	done := notifyReloading()
-	defer done()
-
 	if err := config.Reload(*cli.configFile, cli.flags, reload); err != nil {
 		log.G(ctx).WithError(err).Error("Error reloading configuration")
 		return

daemon/command/daemon_freebsd.go

@@ -11,10 +11,6 @@ func preNotifyReady() error {
 func notifyReady() {
 }
 
-// notifyReloading sends a message to the host when the server got signaled to
-// reloading its configuration. It is a no-op on FreeBSD.
-func notifyReloading() func() { return func() {} }
-
 // notifyStopping sends a message to the host when the server is shutting down
 func notifyStopping() {
 }

daemon/command/daemon_linux.go

@@ -58,25 +58,6 @@ func notifyStopping() {
 	_, _ = systemdDaemon.SdNotify(false, systemdDaemon.SdNotifyStopping)
 }
 
-// notifyReloading sends a message to the host when the server got signaled to
-// reloading its configuration, see [sd_notify(3)]. The server should be running
-// as a systemd unit with "Type=notify" or "Type=notify-reload" (see
-// [systemd.service(5)]).
-//
-// notifyReloading returns a callback that must be called after reloading completes
-// (either successfully or unsuccessfully) to send [notifyReady].
-//
-// [sd_notify(3)]: https://www.freedesktop.org/software/systemd/man/latest/sd_notify.html#RELOADING=1
-// [systemd.service(5)]: https://www.freedesktop.org/software/systemd/man/latest/systemd.service.html#Type=
-func notifyReloading() (done func()) {
-	sent, _ := systemdDaemon.SdNotify(false, systemdDaemon.SdNotifyReloading+"\n"+systemdDaemon.SdNotifyMonotonicUsec())
-	if !sent {
-		// Nothing to do if no reloading event was sent.
-		return func() {}
-	}
-	return notifyReady
-}
-
 func validateCPURealtimeOptions(cfg *config.Config) error {
 	if cfg.CPURealtimePeriod == 0 && cfg.CPURealtimeRuntime == 0 {
 		return nil

daemon/command/daemon_windows.go

@@ -56,10 +56,6 @@ func preNotifyReady() error {
 func notifyReady() {
 }
 
-// notifyReloading sends a message to the host when the server got signaled to
-// reloading its configuration. It is a no-op on Windows.
-func notifyReloading() func() { return func() {} }
-
 // notifyStopping sends a message to the host when the server is shutting down
 func notifyStopping() {
 }