Take advantage of new UCOM and bus functionality so that

the device_detach() function doesn't block on UCOM device
drivers until the TTY handle is closed by the userspace
application. This is implemented by a postpone of the
softc free where the UCOM structures reside until the
TTY references are gone.

Discussed with:	kib, ed
MFC after:	2 weeks

1 files changed, 26 insertions, 2 deletions

diff --git a/sys/dev/usb/serial/umct.c b/sys/dev/usb/serial/umct.c
index 16dd4a1..eaab705 100644
--- a/sys/dev/usb/serial/umct.c
+++ b/sys/dev/usb/serial/umct.c
@@ -123,6 +123,7 @@ struct umct_softc {
 static device_probe_t umct_probe;
 static device_attach_t umct_attach;
 static device_detach_t umct_detach;
+static device_free_softc_t umct_free_softc;
 
 static usb_callback_t umct_intr_callback;
 static usb_callback_t umct_intr_callback_sub;
@@ -132,6 +133,7 @@ static usb_callback_t umct_write_callback;
 
 static void	umct_cfg_do_request(struct umct_softc *sc, uint8_t request,
 		    uint16_t len, uint32_t value);
+static void	umct_free(struct ucom_softc *);
 static void	umct_cfg_get_status(struct ucom_softc *, uint8_t *,
 		    uint8_t *);
 static void	umct_cfg_set_break(struct ucom_softc *, uint8_t);
@@ -190,6 +192,7 @@ static const struct ucom_callback umct_callback = {
 	.ucom_start_write = &umct_start_write,
 	.ucom_stop_write = &umct_stop_write,
 	.ucom_poll = &umct_poll,
+	.ucom_free = &umct_free,
 };
 
 static const STRUCT_USB_HOST_ID umct_devs[] = {
@@ -204,7 +207,8 @@ static device_method_t umct_methods[] = {
 	DEVMETHOD(device_probe, umct_probe),
 	DEVMETHOD(device_attach, umct_attach),
 	DEVMETHOD(device_detach, umct_detach),
-	{0, 0}
+	DEVMETHOD(device_free_softc, umct_free_softc),
+	DEVMETHOD_END
 };
 
 static devclass_t umct_devclass;
@@ -251,6 +255,7 @@ umct_attach(device_t dev)
 
 	device_set_usb_desc(dev);
 	mtx_init(&sc->sc_mtx, "umct", NULL, MTX_DEF);
+	ucom_ref(&sc->sc_super_ucom);
 
 	snprintf(sc->sc_name, sizeof(sc->sc_name),
 	    "%s", device_get_nameunit(dev));
@@ -312,11 +317,30 @@ umct_detach(device_t dev)
 
 	ucom_detach(&sc->sc_super_ucom, &sc->sc_ucom);
 	usbd_transfer_unsetup(sc->sc_xfer, UMCT_N_TRANSFER);
-	mtx_destroy(&sc->sc_mtx);
 
 	return (0);
 }
 
+UCOM_UNLOAD_DRAIN(umct);
+
+static void
+umct_free_softc(device_t dev, void *arg)
+{
+	struct umct_softc *sc = arg;
+
+	if (ucom_unref(&sc->sc_super_ucom)) {
+		if (mtx_initialized(&sc->sc_mtx))
+			mtx_destroy(&sc->sc_mtx);
+		device_free_softc(dev, sc);
+	}
+}
+
+static void
+umct_free(struct ucom_softc *ucom)
+{
+	umct_free_softc(NULL, ucom->sc_parent);
+}
+
 static void
 umct_cfg_do_request(struct umct_softc *sc, uint8_t request,
     uint16_t len, uint32_t value)