From 13bd84042e7965cb455b03d55dba5440d3d47154 Mon Sep 17 00:00:00 2001
From: Andrew Thompson <thompsa@FreeBSD.org>
Date: Tue, 13 Jan 2009 19:03:12 +0000
Subject: [PATCH] MFp4: //depot/projects/usb@155839

	This change is about removing three fields from "struct usb2_xfer"
	which can be reached from "struct usb2_xfer_root" instead and cleaning
	up the code after this change. The fields are "xfer->udev",
	"xfer->xfer_mtx" and "xfer->usb2_sc". In this process the following
	changes were also made:
	Rename "usb2_root" to "xroot" which is short for "xfer root".
	Rename "priv_mtx" to "xfer_mtx" in USB core.
	The USB_XFER_LOCK and USB_XFER_UNLOCK macros should only be used in
	the USB core due to dependency towards "xroot". Substitute macros
	for the real lock in two USB device drivers.

Submitted by: Hans Petter Selasky
---
 sys/dev/usb2/controller/at91dci.c       |  39 +++--
 sys/dev/usb2/controller/ehci2.c         |  85 +++++------
 sys/dev/usb2/controller/musb2_otg.c     |  43 +++---
 sys/dev/usb2/controller/ohci2.c         |  55 +++----
 sys/dev/usb2/controller/uhci2.c         |  63 ++++----
 sys/dev/usb2/controller/uss820dci.c     |  35 ++---
 sys/dev/usb2/core/usb2_busdma.c         |  14 +-
 sys/dev/usb2/core/usb2_core.h           |  11 +-
 sys/dev/usb2/core/usb2_debug.c          |  12 +-
 sys/dev/usb2/core/usb2_handle_request.c |  22 +--
 sys/dev/usb2/core/usb2_hub.c            |   2 +-
 sys/dev/usb2/core/usb2_request.c        |  28 ++--
 sys/dev/usb2/core/usb2_transfer.c       | 192 ++++++++++++------------
 sys/dev/usb2/core/usb2_transfer.h       |  10 +-
 sys/dev/usb2/serial/uvscom2.c           |   4 +-
 sys/dev/usb2/storage/ata-usb2.c         |   5 +-
 16 files changed, 299 insertions(+), 321 deletions(-)

diff --git a/sys/dev/usb2/controller/at91dci.c b/sys/dev/usb2/controller/at91dci.c
index e3f72006b4f3..2450ae436aca 100644
--- a/sys/dev/usb2/controller/at91dci.c
+++ b/sys/dev/usb2/controller/at91dci.c
@@ -259,13 +259,13 @@ at91dci_pull_down(struct at91dci_softc *sc)
 static void
 at91dci_wakeup_peer(struct usb2_xfer *xfer)
 {
-	struct at91dci_softc *sc = xfer->usb2_sc;
+	struct at91dci_softc *sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 	uint8_t use_polling;
 
 	if (!(sc->sc_flags.status_suspend)) {
 		return;
 	}
-	use_polling = mtx_owned(xfer->xfer_mtx) ? 1 : 0;
+	use_polling = mtx_owned(xfer->xroot->xfer_mtx) ? 1 : 0;
 
 	AT91_UDP_WRITE_4(sc, AT91_UDP_GSTATE, AT91_UDP_GSTATE_ESR);
 
@@ -698,7 +698,7 @@ at91dci_xfer_do_fifo(struct usb2_xfer *xfer)
 	return (1);			/* not complete */
 
 done:
-	sc = xfer->usb2_sc;
+	sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 	temp = (xfer->endpoint & UE_ADDR);
 
 	/* update FIFO bank flag and multi buffer */
@@ -886,7 +886,7 @@ at91dci_setup_standard_chain(struct usb2_xfer *xfer)
 
 	DPRINTFN(9, "addr=%d endpt=%d sumlen=%d speed=%d\n",
 	    xfer->address, UE_GET_ADDR(xfer->endpoint),
-	    xfer->sumlen, usb2_get_speed(xfer->udev));
+	    xfer->sumlen, usb2_get_speed(xfer->xroot->udev));
 
 	temp.max_frame_size = xfer->max_frame_size;
 
@@ -901,7 +901,7 @@ at91dci_setup_standard_chain(struct usb2_xfer *xfer)
 	temp.setup_alt_next = xfer->flags_int.short_frames_ok;
 	temp.offset = 0;
 
-	sc = xfer->usb2_sc;
+	sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 	ep_no = (xfer->endpoint & UE_ADDR);
 
 	/* check if we should prepend a setup message */
@@ -1042,7 +1042,7 @@ at91dci_start_standard_chain(struct usb2_xfer *xfer)
 	/* poll one time */
 	if (at91dci_xfer_do_fifo(xfer)) {
 
-		struct at91dci_softc *sc = xfer->usb2_sc;
+		struct at91dci_softc *sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 		uint8_t ep_no = xfer->endpoint & UE_ADDR;
 
 		/*
@@ -1055,7 +1055,7 @@ at91dci_start_standard_chain(struct usb2_xfer *xfer)
 		DPRINTFN(15, "enable interrupts on endpoint %d\n", ep_no);
 
 		/* put transfer on interrupt queue */
-		usb2_transfer_enqueue(&xfer->udev->bus->intr_q, xfer);
+		usb2_transfer_enqueue(&xfer->xroot->bus->intr_q, xfer);
 
 		/* start timeout, if any */
 		if (xfer->timeout != 0) {
@@ -1069,7 +1069,7 @@ static void
 at91dci_root_intr_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	struct at91dci_softc *sc = xfer->usb2_sc;
+	struct at91dci_softc *sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 
 	DPRINTFN(9, "\n");
 
@@ -1209,7 +1209,7 @@ at91dci_standard_done(struct usb2_xfer *xfer)
 static void
 at91dci_device_done(struct usb2_xfer *xfer, usb2_error_t error)
 {
-	struct at91dci_softc *sc = xfer->usb2_sc;
+	struct at91dci_softc *sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 	uint8_t ep_no;
 
 	USB_BUS_LOCK_ASSERT(&sc->sc_bus, MA_OWNED);
@@ -1623,7 +1623,7 @@ at91dci_device_isoc_fs_close(struct usb2_xfer *xfer)
 static void
 at91dci_device_isoc_fs_enter(struct usb2_xfer *xfer)
 {
-	struct at91dci_softc *sc = xfer->usb2_sc;
+	struct at91dci_softc *sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 	uint32_t temp;
 	uint32_t nframes;
 
@@ -1705,7 +1705,7 @@ at91dci_root_ctrl_open(struct usb2_xfer *xfer)
 static void
 at91dci_root_ctrl_close(struct usb2_xfer *xfer)
 {
-	struct at91dci_softc *sc = xfer->usb2_sc;
+	struct at91dci_softc *sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_ctrl.xfer == xfer) {
 		sc->sc_root_ctrl.xfer = NULL;
@@ -1809,11 +1809,11 @@ at91dci_root_ctrl_enter(struct usb2_xfer *xfer)
 static void
 at91dci_root_ctrl_start(struct usb2_xfer *xfer)
 {
-	struct at91dci_softc *sc = xfer->usb2_sc;
+	struct at91dci_softc *sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_root_ctrl.xfer = xfer;
 
-	usb2_bus_roothub_exec(xfer->udev->bus);
+	usb2_bus_roothub_exec(xfer->xroot->bus);
 }
 
 static void
@@ -1826,7 +1826,7 @@ static void
 at91dci_root_ctrl_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	struct at91dci_softc *sc = xfer->usb2_sc;
+	struct at91dci_softc *sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 	uint16_t value;
 	uint16_t index;
 	uint8_t use_polling;
@@ -1847,7 +1847,7 @@ at91dci_root_ctrl_done(struct usb2_xfer *xfer,
 	value = UGETW(std->req.wValue);
 	index = UGETW(std->req.wIndex);
 
-	use_polling = mtx_owned(xfer->xfer_mtx) ? 1 : 0;
+	use_polling = mtx_owned(xfer->xroot->xfer_mtx) ? 1 : 0;
 
 	/* demultiplex the control request */
 
@@ -2252,7 +2252,7 @@ at91dci_root_intr_open(struct usb2_xfer *xfer)
 static void
 at91dci_root_intr_close(struct usb2_xfer *xfer)
 {
-	struct at91dci_softc *sc = xfer->usb2_sc;
+	struct at91dci_softc *sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_intr.xfer == xfer) {
 		sc->sc_root_intr.xfer = NULL;
@@ -2269,7 +2269,7 @@ at91dci_root_intr_enter(struct usb2_xfer *xfer)
 static void
 at91dci_root_intr_start(struct usb2_xfer *xfer)
 {
-	struct at91dci_softc *sc = xfer->usb2_sc;
+	struct at91dci_softc *sc = AT9100_DCI_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_root_intr.xfer = xfer;
 }
@@ -2298,11 +2298,6 @@ at91dci_xfer_setup(struct usb2_setup_params *parm)
 	sc = AT9100_DCI_BUS2SC(parm->udev->bus);
 	xfer = parm->curr_xfer;
 
-	/*
-	 * setup xfer
-	 */
-	xfer->usb2_sc = sc;
-
 	/*
 	 * NOTE: This driver does not use any of the parameters that
 	 * are computed from the following values. Just set some
diff --git a/sys/dev/usb2/controller/ehci2.c b/sys/dev/usb2/controller/ehci2.c
index 4667d47dc2b3..2b3ab288ae99 100644
--- a/sys/dev/usb2/controller/ehci2.c
+++ b/sys/dev/usb2/controller/ehci2.c
@@ -971,7 +971,7 @@ ehci_transfer_intr_enqueue(struct usb2_xfer *xfer)
 		return;
 	}
 	/* put transfer on interrupt queue */
-	usb2_transfer_enqueue(&xfer->udev->bus->intr_q, xfer);
+	usb2_transfer_enqueue(&xfer->xroot->bus->intr_q, xfer);
 
 	/* start timeout, if any */
 	if (xfer->timeout != 0) {
@@ -1135,7 +1135,7 @@ _ehci_remove_qh(ehci_qh_t *sqh, ehci_qh_t *last)
 static usb2_error_t
 ehci_non_isoc_done_sub(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 	ehci_qtd_t *td;
 	ehci_qtd_t *td_alt_next;
 	uint32_t status;
@@ -1239,7 +1239,7 @@ ehci_non_isoc_done(struct usb2_xfer *xfer)
 
 #if USB_DEBUG
 	if (ehcidebug > 10) {
-		ehci_softc_t *sc = xfer->usb2_sc;
+		ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 		ehci_dump_sqtds(sc, xfer->td_transfer_first);
 	}
@@ -1291,7 +1291,7 @@ static uint8_t
 ehci_check_transfer(struct usb2_xfer *xfer)
 {
 	struct usb2_pipe_methods *methods = xfer->pipe->methods;
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 	uint32_t status;
 
@@ -1521,7 +1521,7 @@ ehci_timeout(void *arg)
 
 	DPRINTF("xfer=%p\n", xfer);
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	/* transfer is transferred */
 	ehci_device_done(xfer, USB_ERR_TIMEOUT);
@@ -1731,11 +1731,11 @@ ehci_setup_standard_chain(struct usb2_xfer *xfer, ehci_qh_t **qh_last)
 
 	DPRINTFN(9, "addr=%d endpt=%d sumlen=%d speed=%d\n",
 	    xfer->address, UE_GET_ADDR(xfer->endpoint),
-	    xfer->sumlen, usb2_get_speed(xfer->udev));
+	    xfer->sumlen, usb2_get_speed(xfer->xroot->udev));
 
 	temp.average = xfer->max_usb2_frame_size;
 	temp.max_frame_size = xfer->max_frame_size;
-	temp.sc = xfer->usb2_sc;
+	temp.sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 	/* toggle the DMA set we are using */
 	xfer->flags_int.curr_dma_set ^= 1;
@@ -1763,7 +1763,7 @@ ehci_setup_standard_chain(struct usb2_xfer *xfer, ehci_qh_t **qh_last)
 		temp.auto_data_toggle = 1;
 	}
 
-	if (usb2_get_speed(xfer->udev) != USB_SPEED_HIGH) {
+	if (usb2_get_speed(xfer->xroot->udev) != USB_SPEED_HIGH) {
 		/* max 3 retries */
 		temp.qtd_status |=
 		    htoehci32(temp.sc, EHCI_QTD_SET_CERR(3));
@@ -1894,12 +1894,12 @@ ehci_setup_standard_chain(struct usb2_xfer *xfer, ehci_qh_t **qh_last)
 	    EHCI_QH_SET_ENDPT(UE_GET_ADDR(xfer->endpoint)) |
 	    EHCI_QH_SET_MPL(xfer->max_packet_size));
 
-	if (usb2_get_speed(xfer->udev) == USB_SPEED_HIGH) {
+	if (usb2_get_speed(xfer->xroot->udev) == USB_SPEED_HIGH) {
 		qh_endp |= (EHCI_QH_SET_EPS(EHCI_QH_SPEED_HIGH) |
 		    EHCI_QH_DTC | EHCI_QH_SET_NRL(8));
 	} else {
 
-		if (usb2_get_speed(xfer->udev) == USB_SPEED_FULL) {
+		if (usb2_get_speed(xfer->xroot->udev) == USB_SPEED_FULL) {
 			qh_endp |= (EHCI_QH_SET_EPS(EHCI_QH_SPEED_FULL) |
 			    EHCI_QH_DTC);
 		} else {
@@ -1922,8 +1922,8 @@ ehci_setup_standard_chain(struct usb2_xfer *xfer, ehci_qh_t **qh_last)
 	    (EHCI_QH_SET_MULT(xfer->max_packet_count & 3) |
 	    EHCI_QH_SET_CMASK(xfer->usb2_cmask) |
 	    EHCI_QH_SET_SMASK(xfer->usb2_smask) |
-	    EHCI_QH_SET_HUBA(xfer->udev->hs_hub_addr) |
-	    EHCI_QH_SET_PORT(xfer->udev->hs_port_no));
+	    EHCI_QH_SET_HUBA(xfer->xroot->udev->hs_hub_addr) |
+	    EHCI_QH_SET_PORT(xfer->xroot->udev->hs_port_no));
 
 	qh->qh_endphub = htoehci32(temp.sc, qh_endphub);
 	qh->qh_curqtd = htoehci32(temp.sc, 0);
@@ -1951,7 +1951,7 @@ ehci_setup_standard_chain(struct usb2_xfer *xfer, ehci_qh_t **qh_last)
 
 	usb2_pc_cpu_flush(qh->page_cache);
 
-	if (xfer->udev->pwr_save.suspended == 0) {
+	if (xfer->xroot->udev->pwr_save.suspended == 0) {
 		EHCI_APPEND_QH(qh, *qh_last);
 	}
 }
@@ -1960,7 +1960,7 @@ static void
 ehci_root_intr_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 	uint16_t i;
 	uint16_t m;
 
@@ -2117,7 +2117,7 @@ static void
 ehci_device_done(struct usb2_xfer *xfer, usb2_error_t error)
 {
 	struct usb2_pipe_methods *methods = xfer->pipe->methods;
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 	USB_BUS_LOCK_ASSERT(&sc->sc_bus, MA_OWNED);
 
@@ -2130,7 +2130,7 @@ ehci_device_done(struct usb2_xfer *xfer, usb2_error_t error)
 		if (ehcidebug > 8) {
 			DPRINTF("nexttog=%d; data after transfer:\n",
 			    xfer->pipe->toggle_next);
-			ehci_dump_sqtds(xfer->usb2_sc,
+			ehci_dump_sqtds(sc,
 			    xfer->td_transfer_first);
 		}
 #endif
@@ -2185,7 +2185,7 @@ ehci_device_bulk_enter(struct usb2_xfer *xfer)
 static void
 ehci_device_bulk_start(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 	/* setup TD's and QH */
 	ehci_setup_standard_chain(xfer, &sc->sc_async_p_last);
@@ -2228,7 +2228,7 @@ ehci_device_ctrl_enter(struct usb2_xfer *xfer)
 static void
 ehci_device_ctrl_start(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 	/* setup TD's and QH */
 	ehci_setup_standard_chain(xfer, &sc->sc_async_p_last);
@@ -2253,7 +2253,7 @@ struct usb2_pipe_methods ehci_device_ctrl_methods =
 static void
 ehci_device_intr_open(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 	uint16_t best;
 	uint16_t bit;
 	uint16_t x;
@@ -2262,9 +2262,9 @@ ehci_device_intr_open(struct usb2_xfer *xfer)
 	/* Allocate a microframe slot first: */
 
 	slot = usb2_intr_schedule_adjust
-	    (xfer->udev, xfer->max_frame_size, USB_HS_MICRO_FRAMES_MAX);
+	    (xfer->xroot->udev, xfer->max_frame_size, USB_HS_MICRO_FRAMES_MAX);
 
-	if (usb2_get_speed(xfer->udev) == USB_SPEED_HIGH) {
+	if (usb2_get_speed(xfer->xroot->udev) == USB_SPEED_HIGH) {
 		xfer->usb2_uframe = slot;
 		xfer->usb2_smask = (1 << slot) & 0xFF;
 		xfer->usb2_cmask = 0;
@@ -2306,11 +2306,11 @@ ehci_device_intr_open(struct usb2_xfer *xfer)
 static void
 ehci_device_intr_close(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 	uint8_t slot;
 
 	slot = usb2_intr_schedule_adjust
-	    (xfer->udev, -(xfer->max_frame_size), xfer->usb2_uframe);
+	    (xfer->xroot->udev, -(xfer->max_frame_size), xfer->usb2_uframe);
 
 	sc->sc_intr_stat[xfer->qh_pos]--;
 
@@ -2326,7 +2326,7 @@ ehci_device_intr_enter(struct usb2_xfer *xfer)
 static void
 ehci_device_intr_start(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 	/* setup TD's and QH */
 	ehci_setup_standard_chain(xfer, &sc->sc_intr_p_last[xfer->qh_pos]);
@@ -2351,7 +2351,7 @@ struct usb2_pipe_methods ehci_device_intr_methods =
 static void
 ehci_device_isoc_fs_open(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 	ehci_sitd_t *td;
 	uint32_t sitd_portaddr;
 	uint8_t ds;
@@ -2359,8 +2359,8 @@ ehci_device_isoc_fs_open(struct usb2_xfer *xfer)
 	sitd_portaddr =
 	    EHCI_SITD_SET_ADDR(xfer->address) |
 	    EHCI_SITD_SET_ENDPT(UE_GET_ADDR(xfer->endpoint)) |
-	    EHCI_SITD_SET_HUBA(xfer->udev->hs_hub_addr) |
-	    EHCI_SITD_SET_PORT(xfer->udev->hs_port_no);
+	    EHCI_SITD_SET_HUBA(xfer->xroot->udev->hs_hub_addr) |
+	    EHCI_SITD_SET_PORT(xfer->xroot->udev->hs_port_no);
 
 	if (UE_GET_DIR(xfer->endpoint) == UE_DIR_IN) {
 		sitd_portaddr |= EHCI_SITD_SET_DIR_IN;
@@ -2399,7 +2399,7 @@ static void
 ehci_device_isoc_fs_enter(struct usb2_xfer *xfer)
 {
 	struct usb2_page_search buf_res;
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 	struct usb2_fs_isoc_schedule *fss_start;
 	struct usb2_fs_isoc_schedule *fss_end;
 	struct usb2_fs_isoc_schedule *fss;
@@ -2460,7 +2460,7 @@ ehci_device_isoc_fs_enter(struct usb2_xfer *xfer)
 	 */
 	xfer->isoc_time_complete =
 	    usb2_fs_isoc_schedule_isoc_time_expand
-	    (xfer->udev, &fss_start, &fss_end, nframes) + buf_offset +
+	    (xfer->xroot->udev, &fss_start, &fss_end, nframes) + buf_offset +
 	    xfer->nframes;
 
 	/* get the real number of frames */
@@ -2636,7 +2636,7 @@ struct usb2_pipe_methods ehci_device_isoc_fs_methods =
 static void
 ehci_device_isoc_hs_open(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 	ehci_itd_t *td;
 	uint32_t temp;
 	uint8_t ds;
@@ -2690,7 +2690,7 @@ static void
 ehci_device_isoc_hs_enter(struct usb2_xfer *xfer)
 {
 	struct usb2_page_search buf_res;
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 	ehci_itd_t *td;
 	ehci_itd_t *td_last = NULL;
 	ehci_itd_t **pp_last;
@@ -2914,7 +2914,7 @@ ehci_root_ctrl_open(struct usb2_xfer *xfer)
 static void
 ehci_root_ctrl_close(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_ctrl.xfer == xfer) {
 		sc->sc_root_ctrl.xfer = NULL;
@@ -3021,13 +3021,13 @@ ehci_root_ctrl_enter(struct usb2_xfer *xfer)
 static void
 ehci_root_ctrl_start(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 	DPRINTF("\n");
 
 	sc->sc_root_ctrl.xfer = xfer;
 
-	usb2_bus_roothub_exec(xfer->udev->bus);
+	usb2_bus_roothub_exec(xfer->xroot->bus);
 }
 
 static void
@@ -3040,7 +3040,7 @@ static void
 ehci_root_ctrl_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 	char *ptr;
 	uint32_t port;
 	uint32_t v;
@@ -3066,7 +3066,7 @@ ehci_root_ctrl_done(struct usb2_xfer *xfer,
 	value = UGETW(std->req.wValue);
 	index = UGETW(std->req.wIndex);
 
-	use_polling = mtx_owned(xfer->xfer_mtx) ? 1 : 0;
+	use_polling = mtx_owned(xfer->xroot->xfer_mtx) ? 1 : 0;
 
 	DPRINTFN(3, "type=0x%02x request=0x%02x wLen=0x%04x "
 	    "wValue=0x%04x wIndex=0x%04x\n",
@@ -3483,7 +3483,7 @@ ehci_root_intr_open(struct usb2_xfer *xfer)
 static void
 ehci_root_intr_close(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_intr.xfer == xfer) {
 		sc->sc_root_intr.xfer = NULL;
@@ -3500,7 +3500,7 @@ ehci_root_intr_enter(struct usb2_xfer *xfer)
 static void
 ehci_root_intr_start(struct usb2_xfer *xfer)
 {
-	ehci_softc_t *sc = xfer->usb2_sc;
+	ehci_softc_t *sc = EHCI_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_root_intr.xfer = xfer;
 }
@@ -3537,11 +3537,6 @@ ehci_xfer_setup(struct usb2_setup_params *parm)
 	nsitd = 0;
 	nitd = 0;
 
-	/*
-	 * setup xfer
-	 */
-	xfer->usb2_sc = sc;
-
 	/*
 	 * compute maximum number of some structures
 	 */
@@ -3864,7 +3859,7 @@ ehci_device_resume(struct usb2_device *udev)
 
 	TAILQ_FOREACH(xfer, &sc->sc_bus.intr_q.head, wait_entry) {
 
-		if (xfer->udev == udev) {
+		if (xfer->xroot->udev == udev) {
 
 			methods = xfer->pipe->methods;
 
@@ -3898,7 +3893,7 @@ ehci_device_suspend(struct usb2_device *udev)
 
 	TAILQ_FOREACH(xfer, &sc->sc_bus.intr_q.head, wait_entry) {
 
-		if (xfer->udev == udev) {
+		if (xfer->xroot->udev == udev) {
 
 			methods = xfer->pipe->methods;
 
diff --git a/sys/dev/usb2/controller/musb2_otg.c b/sys/dev/usb2/controller/musb2_otg.c
index 0da5dfb85030..899a73faafc0 100644
--- a/sys/dev/usb2/controller/musb2_otg.c
+++ b/sys/dev/usb2/controller/musb2_otg.c
@@ -204,14 +204,14 @@ musbotg_pull_down(struct musbotg_softc *sc)
 static void
 musbotg_wakeup_peer(struct usb2_xfer *xfer)
 {
-	struct musbotg_softc *sc = xfer->usb2_sc;
+	struct musbotg_softc *sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 	uint8_t temp;
 	uint8_t use_polling;
 
 	if (!(sc->sc_flags.status_suspend)) {
 		return;
 	}
-	use_polling = mtx_owned(xfer->xfer_mtx) ? 1 : 0;
+	use_polling = mtx_owned(xfer->xroot->xfer_mtx) ? 1 : 0;
 
 	temp = MUSB2_READ_1(sc, MUSB2_REG_POWER);
 	temp |= MUSB2_MASK_RESUME;
@@ -931,7 +931,7 @@ musbotg_xfer_do_fifo(struct usb2_xfer *xfer)
 	return (1);			/* not complete */
 
 done:
-	sc = xfer->usb2_sc;
+	sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 
 	/* compute all actual lengths */
 
@@ -1130,7 +1130,7 @@ musbotg_setup_standard_chain(struct usb2_xfer *xfer)
 
 	DPRINTFN(8, "addr=%d endpt=%d sumlen=%d speed=%d\n",
 	    xfer->address, UE_GET_ADDR(xfer->endpoint),
-	    xfer->sumlen, usb2_get_speed(xfer->udev));
+	    xfer->sumlen, usb2_get_speed(xfer->xroot->udev));
 
 	temp.max_frame_size = xfer->max_frame_size;
 
@@ -1145,7 +1145,7 @@ musbotg_setup_standard_chain(struct usb2_xfer *xfer)
 	temp.setup_alt_next = xfer->flags_int.short_frames_ok;
 	temp.offset = 0;
 
-	sc = xfer->usb2_sc;
+	sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 	ep_no = (xfer->endpoint & UE_ADDR);
 
 	/* check if we should prepend a setup message */
@@ -1245,7 +1245,7 @@ musbotg_timeout(void *arg)
 
 	DPRINTFN(1, "xfer=%p\n", xfer);
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	/* transfer is transferred */
 	musbotg_device_done(xfer, USB_ERR_TIMEOUT);
@@ -1254,7 +1254,7 @@ musbotg_timeout(void *arg)
 static void
 musbotg_ep_int_set(struct usb2_xfer *xfer, uint8_t on)
 {
-	struct musbotg_softc *sc = xfer->usb2_sc;
+	struct musbotg_softc *sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 	uint16_t temp;
 	uint8_t ep_no = xfer->endpoint & UE_ADDR;
 
@@ -1304,7 +1304,7 @@ musbotg_start_standard_chain(struct usb2_xfer *xfer)
 		DPRINTFN(14, "enabled interrupts on endpoint\n");
 
 		/* put transfer on interrupt queue */
-		usb2_transfer_enqueue(&xfer->udev->bus->intr_q, xfer);
+		usb2_transfer_enqueue(&xfer->xroot->bus->intr_q, xfer);
 
 		/* start timeout, if any */
 		if (xfer->timeout != 0) {
@@ -1318,7 +1318,7 @@ static void
 musbotg_root_intr_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	struct musbotg_softc *sc = xfer->usb2_sc;
+	struct musbotg_softc *sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 
 	DPRINTFN(8, "\n");
 
@@ -1458,7 +1458,7 @@ musbotg_standard_done(struct usb2_xfer *xfer)
 static void
 musbotg_device_done(struct usb2_xfer *xfer, usb2_error_t error)
 {
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	DPRINTFN(2, "xfer=%p, pipe=%p, error=%d\n",
 	    xfer, xfer->pipe, error);
@@ -2021,7 +2021,7 @@ musbotg_device_isoc_close(struct usb2_xfer *xfer)
 static void
 musbotg_device_isoc_enter(struct usb2_xfer *xfer)
 {
-	struct musbotg_softc *sc = xfer->usb2_sc;
+	struct musbotg_softc *sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 	uint32_t temp;
 	uint32_t nframes;
 	uint32_t fs_frames;
@@ -2039,7 +2039,7 @@ musbotg_device_isoc_enter(struct usb2_xfer *xfer)
 	 */
 	temp = (nframes - xfer->pipe->isoc_next) & MUSB2_MASK_FRAME;
 
-	if (usb2_get_speed(xfer->udev) == USB_SPEED_HIGH) {
+	if (usb2_get_speed(xfer->xroot->udev) == USB_SPEED_HIGH) {
 		fs_frames = (xfer->nframes + 7) / 8;
 	} else {
 		fs_frames = xfer->nframes;
@@ -2109,7 +2109,7 @@ musbotg_root_ctrl_open(struct usb2_xfer *xfer)
 static void
 musbotg_root_ctrl_close(struct usb2_xfer *xfer)
 {
-	struct musbotg_softc *sc = xfer->usb2_sc;
+	struct musbotg_softc *sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_ctrl.xfer == xfer) {
 		sc->sc_root_ctrl.xfer = NULL;
@@ -2214,11 +2214,11 @@ musbotg_root_ctrl_enter(struct usb2_xfer *xfer)
 static void
 musbotg_root_ctrl_start(struct usb2_xfer *xfer)
 {
-	struct musbotg_softc *sc = xfer->usb2_sc;
+	struct musbotg_softc *sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_root_ctrl.xfer = xfer;
 
-	usb2_bus_roothub_exec(xfer->udev->bus);
+	usb2_bus_roothub_exec(xfer->xroot->bus);
 }
 
 static void
@@ -2231,7 +2231,7 @@ static void
 musbotg_root_ctrl_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	struct musbotg_softc *sc = xfer->usb2_sc;
+	struct musbotg_softc *sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 	uint16_t value;
 	uint16_t index;
 	uint8_t use_polling;
@@ -2252,7 +2252,7 @@ musbotg_root_ctrl_done(struct usb2_xfer *xfer,
 	value = UGETW(std->req.wValue);
 	index = UGETW(std->req.wIndex);
 
-	use_polling = mtx_owned(xfer->xfer_mtx) ? 1 : 0;
+	use_polling = mtx_owned(xfer->xroot->xfer_mtx) ? 1 : 0;
 
 	/* demultiplex the control request */
 
@@ -2660,7 +2660,7 @@ musbotg_root_intr_open(struct usb2_xfer *xfer)
 static void
 musbotg_root_intr_close(struct usb2_xfer *xfer)
 {
-	struct musbotg_softc *sc = xfer->usb2_sc;
+	struct musbotg_softc *sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_intr.xfer == xfer) {
 		sc->sc_root_intr.xfer = NULL;
@@ -2677,7 +2677,7 @@ musbotg_root_intr_enter(struct usb2_xfer *xfer)
 static void
 musbotg_root_intr_start(struct usb2_xfer *xfer)
 {
-	struct musbotg_softc *sc = xfer->usb2_sc;
+	struct musbotg_softc *sc = MUSBOTG_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_root_intr.xfer = xfer;
 }
@@ -2706,11 +2706,6 @@ musbotg_xfer_setup(struct usb2_setup_params *parm)
 	sc = MUSBOTG_BUS2SC(parm->udev->bus);
 	xfer = parm->curr_xfer;
 
-	/*
-	 * setup xfer
-	 */
-	xfer->usb2_sc = sc;
-
 	/*
 	 * NOTE: This driver does not use any of the parameters that
 	 * are computed from the following values. Just set some
diff --git a/sys/dev/usb2/controller/ohci2.c b/sys/dev/usb2/controller/ohci2.c
index 2e24889a9f6f..cca34e846a7e 100644
--- a/sys/dev/usb2/controller/ohci2.c
+++ b/sys/dev/usb2/controller/ohci2.c
@@ -669,7 +669,7 @@ ohci_transfer_intr_enqueue(struct usb2_xfer *xfer)
 		return;
 	}
 	/* put transfer on interrupt queue */
-	usb2_transfer_enqueue(&xfer->udev->bus->intr_q, xfer);
+	usb2_transfer_enqueue(&xfer->xroot->bus->intr_q, xfer);
 
 	/* start timeout, if any */
 	if (xfer->timeout != 0) {
@@ -1233,7 +1233,7 @@ ohci_timeout(void *arg)
 
 	DPRINTF("xfer=%p\n", xfer);
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	/* transfer is transferred */
 	ohci_device_done(xfer, USB_ERR_TIMEOUT);
@@ -1404,7 +1404,7 @@ ohci_setup_standard_chain(struct usb2_xfer *xfer, ohci_ed_t **ed_last)
 
 	DPRINTFN(9, "addr=%d endpt=%d sumlen=%d speed=%d\n",
 	    xfer->address, UE_GET_ADDR(xfer->endpoint),
-	    xfer->sumlen, usb2_get_speed(xfer->udev));
+	    xfer->sumlen, usb2_get_speed(xfer->xroot->udev));
 
 	temp.average = xfer->max_usb2_frame_size;
 	temp.max_frame_size = xfer->max_frame_size;
@@ -1549,7 +1549,7 @@ ohci_setup_standard_chain(struct usb2_xfer *xfer, ohci_ed_t **ed_last)
 
 	ed_flags |= (OHCI_ED_FORMAT_GEN | OHCI_ED_DIR_TD);
 
-	if (xfer->udev->speed == USB_SPEED_LOW) {
+	if (xfer->xroot->udev->speed == USB_SPEED_LOW) {
 		ed_flags |= OHCI_ED_SPEED;
 	}
 	ed->ed_flags = htole32(ed_flags);
@@ -1558,17 +1558,17 @@ ohci_setup_standard_chain(struct usb2_xfer *xfer, ohci_ed_t **ed_last)
 
 	ed->ed_headp = td->td_self;
 
-	if (xfer->udev->pwr_save.suspended == 0) {
+	if (xfer->xroot->udev->pwr_save.suspended == 0) {
 		/* the append function will flush the endpoint descriptor */
 		OHCI_APPEND_QH(ed, *ed_last);
 
 		if (methods == &ohci_device_bulk_methods) {
-			ohci_softc_t *sc = xfer->usb2_sc;
+			ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 
 			OWRITE4(sc, OHCI_COMMAND_STATUS, OHCI_BLF);
 		}
 		if (methods == &ohci_device_ctrl_methods) {
-			ohci_softc_t *sc = xfer->usb2_sc;
+			ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 
 			OWRITE4(sc, OHCI_COMMAND_STATUS, OHCI_CLF);
 		}
@@ -1581,7 +1581,7 @@ static void
 ohci_root_intr_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 	uint32_t hstatus;
 	uint16_t i;
 	uint16_t m;
@@ -1629,7 +1629,7 @@ static void
 ohci_device_done(struct usb2_xfer *xfer, usb2_error_t error)
 {
 	struct usb2_pipe_methods *methods = xfer->pipe->methods;
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 	ohci_ed_t *ed;
 
 	USB_BUS_LOCK_ASSERT(&sc->sc_bus, MA_OWNED);
@@ -1685,7 +1685,7 @@ ohci_device_bulk_enter(struct usb2_xfer *xfer)
 static void
 ohci_device_bulk_start(struct usb2_xfer *xfer)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 
 	/* setup TD's and QH */
 	ohci_setup_standard_chain(xfer, &sc->sc_bulk_p_last);
@@ -1728,7 +1728,7 @@ ohci_device_ctrl_enter(struct usb2_xfer *xfer)
 static void
 ohci_device_ctrl_start(struct usb2_xfer *xfer)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 
 	/* setup TD's and QH */
 	ohci_setup_standard_chain(xfer, &sc->sc_ctrl_p_last);
@@ -1753,7 +1753,7 @@ struct usb2_pipe_methods ohci_device_ctrl_methods =
 static void
 ohci_device_intr_open(struct usb2_xfer *xfer)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 	uint16_t best;
 	uint16_t bit;
 	uint16_t x;
@@ -1786,7 +1786,7 @@ ohci_device_intr_open(struct usb2_xfer *xfer)
 static void
 ohci_device_intr_close(struct usb2_xfer *xfer)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_intr_stat[xfer->qh_pos]--;
 
@@ -1802,7 +1802,7 @@ ohci_device_intr_enter(struct usb2_xfer *xfer)
 static void
 ohci_device_intr_start(struct usb2_xfer *xfer)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 
 	/* setup TD's and QH */
 	ohci_setup_standard_chain(xfer, &sc->sc_intr_p_last[xfer->qh_pos]);
@@ -1841,7 +1841,7 @@ static void
 ohci_device_isoc_enter(struct usb2_xfer *xfer)
 {
 	struct usb2_page_search buf_res;
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 	struct ohci_hcca *hcca;
 	uint32_t buf_offset;
 	uint32_t nframes;
@@ -1999,7 +1999,7 @@ ohci_device_isoc_enter(struct usb2_xfer *xfer)
 	    OHCI_ED_SET_EN(UE_GET_ADDR(xfer->endpoint)) |
 	    OHCI_ED_SET_MAXP(xfer->max_frame_size));
 
-	if (xfer->udev->speed == USB_SPEED_LOW) {
+	if (xfer->xroot->udev->speed == USB_SPEED_LOW) {
 		ed_flags |= OHCI_ED_SPEED;
 	}
 	ed->ed_flags = htole32(ed_flags);
@@ -2047,7 +2047,7 @@ ohci_root_ctrl_open(struct usb2_xfer *xfer)
 static void
 ohci_root_ctrl_close(struct usb2_xfer *xfer)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_ctrl.xfer == xfer) {
 		sc->sc_root_ctrl.xfer = NULL;
@@ -2127,11 +2127,11 @@ ohci_root_ctrl_enter(struct usb2_xfer *xfer)
 static void
 ohci_root_ctrl_start(struct usb2_xfer *xfer)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_root_ctrl.xfer = xfer;
 
-	usb2_bus_roothub_exec(xfer->udev->bus);
+	usb2_bus_roothub_exec(xfer->xroot->bus);
 }
 
 static void
@@ -2144,7 +2144,7 @@ static void
 ohci_root_ctrl_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 	char *ptr;
 	uint32_t port;
 	uint32_t v;
@@ -2169,7 +2169,7 @@ ohci_root_ctrl_done(struct usb2_xfer *xfer,
 	value = UGETW(std->req.wValue);
 	index = UGETW(std->req.wIndex);
 
-	use_polling = mtx_owned(xfer->xfer_mtx) ? 1 : 0;
+	use_polling = mtx_owned(xfer->xroot->xfer_mtx) ? 1 : 0;
 
 	DPRINTFN(3, "type=0x%02x request=0x%02x wLen=0x%04x "
 	    "wValue=0x%04x wIndex=0x%04x\n",
@@ -2470,7 +2470,7 @@ ohci_root_intr_open(struct usb2_xfer *xfer)
 static void
 ohci_root_intr_close(struct usb2_xfer *xfer)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_intr.xfer == xfer) {
 		sc->sc_root_intr.xfer = NULL;
@@ -2487,7 +2487,7 @@ ohci_root_intr_enter(struct usb2_xfer *xfer)
 static void
 ohci_root_intr_start(struct usb2_xfer *xfer)
 {
-	ohci_softc_t *sc = xfer->usb2_sc;
+	ohci_softc_t *sc = OHCI_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_root_intr.xfer = xfer;
 }
@@ -2518,11 +2518,6 @@ ohci_xfer_setup(struct usb2_setup_params *parm)
 	sc = OHCI_BUS2SC(parm->udev->bus);
 	xfer = parm->curr_xfer;
 
-	/*
-	 * setup xfer
-	 */
-	xfer->usb2_sc = sc;
-
 	parm->hc_max_packet_size = 0x500;
 	parm->hc_max_packet_count = 1;
 	parm->hc_max_frame_size = OHCI_PAGE_SIZE;
@@ -2753,7 +2748,7 @@ ohci_device_resume(struct usb2_device *udev)
 
 	TAILQ_FOREACH(xfer, &sc->sc_bus.intr_q.head, wait_entry) {
 
-		if (xfer->udev == udev) {
+		if (xfer->xroot->udev == udev) {
 
 			methods = xfer->pipe->methods;
 			ed = xfer->qh_start[xfer->flags_int.curr_dma_set];
@@ -2791,7 +2786,7 @@ ohci_device_suspend(struct usb2_device *udev)
 
 	TAILQ_FOREACH(xfer, &sc->sc_bus.intr_q.head, wait_entry) {
 
-		if (xfer->udev == udev) {
+		if (xfer->xroot->udev == udev) {
 
 			methods = xfer->pipe->methods;
 			ed = xfer->qh_start[xfer->flags_int.curr_dma_set];
diff --git a/sys/dev/usb2/controller/uhci2.c b/sys/dev/usb2/controller/uhci2.c
index 4bffa3cd4784..e39321888932 100644
--- a/sys/dev/usb2/controller/uhci2.c
+++ b/sys/dev/usb2/controller/uhci2.c
@@ -878,7 +878,7 @@ uhci_transfer_intr_enqueue(struct usb2_xfer *xfer)
 		return;
 	}
 	/* put transfer on interrupt queue */
-	usb2_transfer_enqueue(&xfer->udev->bus->intr_q, xfer);
+	usb2_transfer_enqueue(&xfer->xroot->bus->intr_q, xfer);
 
 	/* start timeout, if any */
 	if (xfer->timeout != 0) {
@@ -1490,7 +1490,7 @@ uhci_timeout(void *arg)
 
 	DPRINTF("xfer=%p\n", xfer);
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	/* transfer is transferred */
 	uhci_device_done(xfer, USB_ERR_TIMEOUT);
@@ -1659,7 +1659,7 @@ uhci_setup_standard_chain(struct usb2_xfer *xfer)
 
 	DPRINTFN(9, "addr=%d endpt=%d sumlen=%d speed=%d\n",
 	    xfer->address, UE_GET_ADDR(xfer->endpoint),
-	    xfer->sumlen, usb2_get_speed(xfer->udev));
+	    xfer->sumlen, usb2_get_speed(xfer->xroot->udev));
 
 	temp.average = xfer->max_frame_size;
 	temp.max_frame_size = xfer->max_frame_size;
@@ -1683,7 +1683,7 @@ uhci_setup_standard_chain(struct usb2_xfer *xfer)
 	    htole32(UHCI_TD_ZERO_ACTLEN(UHCI_TD_SET_ERRCNT(3) |
 	    UHCI_TD_ACTIVE));
 
-	if (xfer->udev->speed == USB_SPEED_LOW) {
+	if (xfer->xroot->udev->speed == USB_SPEED_LOW) {
 		temp.td_status |= htole32(UHCI_TD_LS);
 	}
 	temp.td_token =
@@ -1816,7 +1816,7 @@ static void
 uhci_device_done(struct usb2_xfer *xfer, usb2_error_t error)
 {
 	struct usb2_pipe_methods *methods = xfer->pipe->methods;
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 	uhci_qh_t *qh;
 
 	USB_BUS_LOCK_ASSERT(&sc->sc_bus, MA_OWNED);
@@ -1836,7 +1836,7 @@ uhci_device_done(struct usb2_xfer *xfer, usb2_error_t error)
 		UHCI_REMOVE_QH(qh, sc->sc_bulk_p_last);
 	}
 	if (methods == &uhci_device_ctrl_methods) {
-		if (xfer->udev->speed == USB_SPEED_LOW) {
+		if (xfer->xroot->udev->speed == USB_SPEED_LOW) {
 			UHCI_REMOVE_QH(qh, sc->sc_ls_ctl_p_last);
 		} else {
 			UHCI_REMOVE_QH(qh, sc->sc_fs_ctl_p_last);
@@ -1885,7 +1885,7 @@ uhci_device_bulk_enter(struct usb2_xfer *xfer)
 static void
 uhci_device_bulk_start(struct usb2_xfer *xfer)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 	uhci_td_t *td;
 	uhci_qh_t *qh;
 
@@ -1898,7 +1898,7 @@ uhci_device_bulk_start(struct usb2_xfer *xfer)
 	qh->e_next = td;
 	qh->qh_e_next = td->td_self;
 
-	if (xfer->udev->pwr_save.suspended == 0) {
+	if (xfer->xroot->udev->pwr_save.suspended == 0) {
 		UHCI_APPEND_QH(qh, sc->sc_bulk_p_last);
 		uhci_add_loop(sc);
 		xfer->flags_int.bandwidth_reclaimed = 1;
@@ -1944,7 +1944,7 @@ uhci_device_ctrl_enter(struct usb2_xfer *xfer)
 static void
 uhci_device_ctrl_start(struct usb2_xfer *xfer)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 	uhci_qh_t *qh;
 	uhci_td_t *td;
 
@@ -1961,8 +1961,8 @@ uhci_device_ctrl_start(struct usb2_xfer *xfer)
 	 * NOTE: some devices choke on bandwidth- reclamation for control
 	 * transfers
 	 */
-	if (xfer->udev->pwr_save.suspended == 0) {
-		if (xfer->udev->speed == USB_SPEED_LOW) {
+	if (xfer->xroot->udev->pwr_save.suspended == 0) {
+		if (xfer->xroot->udev->speed == USB_SPEED_LOW) {
 			UHCI_APPEND_QH(qh, sc->sc_ls_ctl_p_last);
 		} else {
 			UHCI_APPEND_QH(qh, sc->sc_fs_ctl_p_last);
@@ -1990,7 +1990,7 @@ struct usb2_pipe_methods uhci_device_ctrl_methods =
 static void
 uhci_device_intr_open(struct usb2_xfer *xfer)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 	uint16_t best;
 	uint16_t bit;
 	uint16_t x;
@@ -2023,7 +2023,7 @@ uhci_device_intr_open(struct usb2_xfer *xfer)
 static void
 uhci_device_intr_close(struct usb2_xfer *xfer)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_intr_stat[xfer->qh_pos]--;
 
@@ -2039,7 +2039,7 @@ uhci_device_intr_enter(struct usb2_xfer *xfer)
 static void
 uhci_device_intr_start(struct usb2_xfer *xfer)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 	uhci_qh_t *qh;
 	uhci_td_t *td;
 
@@ -2052,7 +2052,7 @@ uhci_device_intr_start(struct usb2_xfer *xfer)
 	qh->e_next = td;
 	qh->qh_e_next = td->td_self;
 
-	if (xfer->udev->pwr_save.suspended == 0) {
+	if (xfer->xroot->udev->pwr_save.suspended == 0) {
 
 		/* enter QHs into the controller data structures */
 		UHCI_APPEND_QH(qh, sc->sc_intr_p_last[xfer->qh_pos]);
@@ -2117,7 +2117,7 @@ static void
 uhci_device_isoc_enter(struct usb2_xfer *xfer)
 {
 	struct uhci_mem_layout ml;
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 	uint32_t nframes;
 	uint32_t temp;
 	uint32_t *plen;
@@ -2301,7 +2301,7 @@ uhci_root_ctrl_open(struct usb2_xfer *xfer)
 static void
 uhci_root_ctrl_close(struct usb2_xfer *xfer)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_ctrl.xfer == xfer) {
 		sc->sc_root_ctrl.xfer = NULL;
@@ -2492,13 +2492,13 @@ uhci_root_ctrl_enter(struct usb2_xfer *xfer)
 static void
 uhci_root_ctrl_start(struct usb2_xfer *xfer)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 
 	DPRINTF("\n");
 
 	sc->sc_root_ctrl.xfer = xfer;
 
-	usb2_bus_roothub_exec(xfer->udev->bus);
+	usb2_bus_roothub_exec(xfer->xroot->bus);
 }
 
 static void
@@ -2511,7 +2511,7 @@ static void
 uhci_root_ctrl_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 	char *ptr;
 	uint16_t x;
 	uint16_t port;
@@ -2537,7 +2537,7 @@ uhci_root_ctrl_done(struct usb2_xfer *xfer,
 	value = UGETW(std->req.wValue);
 	index = UGETW(std->req.wIndex);
 
-	use_polling = mtx_owned(xfer->xfer_mtx) ? 1 : 0;
+	use_polling = mtx_owned(xfer->xroot->xfer_mtx) ? 1 : 0;
 
 	DPRINTFN(3, "type=0x%02x request=0x%02x wLen=0x%04x "
 	    "wValue=0x%04x wIndex=0x%04x\n",
@@ -2866,7 +2866,7 @@ uhci_root_intr_open(struct usb2_xfer *xfer)
 static void
 uhci_root_intr_close(struct usb2_xfer *xfer)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_intr.xfer == xfer) {
 		sc->sc_root_intr.xfer = NULL;
@@ -2883,7 +2883,7 @@ uhci_root_intr_enter(struct usb2_xfer *xfer)
 static void
 uhci_root_intr_start(struct usb2_xfer *xfer)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_root_intr.xfer = xfer;
 
@@ -2895,7 +2895,7 @@ static void
 uhci_root_intr_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 
 	USB_BUS_LOCK_ASSERT(&sc->sc_bus, MA_OWNED);
 
@@ -2921,7 +2921,7 @@ static void
 uhci_root_intr_check(void *arg)
 {
 	struct usb2_xfer *xfer = arg;
-	uhci_softc_t *sc = xfer->usb2_sc;
+	uhci_softc_t *sc = UHCI_BUS2SC(xfer->xroot->bus);
 
 	DPRINTFN(21, "\n");
 
@@ -2975,11 +2975,6 @@ uhci_xfer_setup(struct usb2_setup_params *parm)
 	sc = UHCI_BUS2SC(parm->udev->bus);
 	xfer = parm->curr_xfer;
 
-	/*
-	 * setup xfer
-	 */
-	xfer->usb2_sc = sc;
-
 	parm->hc_max_packet_size = 0x500;
 	parm->hc_max_packet_count = 1;
 	parm->hc_max_frame_size = 0x500;
@@ -3241,7 +3236,7 @@ uhci_device_resume(struct usb2_device *udev)
 
 	TAILQ_FOREACH(xfer, &sc->sc_bus.intr_q.head, wait_entry) {
 
-		if (xfer->udev == udev) {
+		if (xfer->xroot->udev == udev) {
 
 			methods = xfer->pipe->methods;
 			qh = xfer->qh_start[xfer->flags_int.curr_dma_set];
@@ -3252,7 +3247,7 @@ uhci_device_resume(struct usb2_device *udev)
 				xfer->flags_int.bandwidth_reclaimed = 1;
 			}
 			if (methods == &uhci_device_ctrl_methods) {
-				if (xfer->udev->speed == USB_SPEED_LOW) {
+				if (xfer->xroot->udev->speed == USB_SPEED_LOW) {
 					UHCI_APPEND_QH(qh, sc->sc_ls_ctl_p_last);
 				} else {
 					UHCI_APPEND_QH(qh, sc->sc_fs_ctl_p_last);
@@ -3283,7 +3278,7 @@ uhci_device_suspend(struct usb2_device *udev)
 
 	TAILQ_FOREACH(xfer, &sc->sc_bus.intr_q.head, wait_entry) {
 
-		if (xfer->udev == udev) {
+		if (xfer->xroot->udev == udev) {
 
 			methods = xfer->pipe->methods;
 			qh = xfer->qh_start[xfer->flags_int.curr_dma_set];
@@ -3296,7 +3291,7 @@ uhci_device_suspend(struct usb2_device *udev)
 				UHCI_REMOVE_QH(qh, sc->sc_bulk_p_last);
 			}
 			if (methods == &uhci_device_ctrl_methods) {
-				if (xfer->udev->speed == USB_SPEED_LOW) {
+				if (xfer->xroot->udev->speed == USB_SPEED_LOW) {
 					UHCI_REMOVE_QH(qh, sc->sc_ls_ctl_p_last);
 				} else {
 					UHCI_REMOVE_QH(qh, sc->sc_fs_ctl_p_last);
diff --git a/sys/dev/usb2/controller/uss820dci.c b/sys/dev/usb2/controller/uss820dci.c
index dc8b10942b39..328bc3e28c5d 100644
--- a/sys/dev/usb2/controller/uss820dci.c
+++ b/sys/dev/usb2/controller/uss820dci.c
@@ -825,7 +825,7 @@ uss820dci_setup_standard_chain(struct usb2_xfer *xfer)
 
 	DPRINTFN(9, "addr=%d endpt=%d sumlen=%d speed=%d\n",
 	    xfer->address, UE_GET_ADDR(xfer->endpoint),
-	    xfer->sumlen, usb2_get_speed(xfer->udev));
+	    xfer->sumlen, usb2_get_speed(xfer->xroot->udev));
 
 	temp.max_frame_size = xfer->max_frame_size;
 
@@ -840,7 +840,7 @@ uss820dci_setup_standard_chain(struct usb2_xfer *xfer)
 	temp.setup_alt_next = xfer->flags_int.short_frames_ok;
 	temp.offset = 0;
 
-	sc = xfer->usb2_sc;
+	sc = USS820_DCI_BUS2SC(xfer->xroot->bus);
 	ep_no = (xfer->endpoint & UE_ADDR);
 
 	/* check if we should prepend a setup message */
@@ -949,7 +949,7 @@ uss820dci_timeout(void *arg)
 
 	DPRINTF("xfer=%p\n", xfer);
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	/* transfer is transferred */
 	uss820dci_device_done(xfer, USB_ERR_TIMEOUT);
@@ -958,7 +958,7 @@ uss820dci_timeout(void *arg)
 static void
 uss820dci_intr_set(struct usb2_xfer *xfer, uint8_t set)
 {
-	struct uss820dci_softc *sc = xfer->usb2_sc;
+	struct uss820dci_softc *sc = USS820_DCI_BUS2SC(xfer->xroot->bus);
 	uint8_t ep_no = (xfer->endpoint & UE_ADDR);
 	uint8_t ep_reg;
 	uint8_t temp;
@@ -1010,7 +1010,7 @@ uss820dci_start_standard_chain(struct usb2_xfer *xfer)
 		uss820dci_intr_set(xfer, 1);
 
 		/* put transfer on interrupt queue */
-		usb2_transfer_enqueue(&xfer->udev->bus->intr_q, xfer);
+		usb2_transfer_enqueue(&xfer->xroot->bus->intr_q, xfer);
 
 		/* start timeout, if any */
 		if (xfer->timeout != 0) {
@@ -1024,7 +1024,7 @@ static void
 uss820dci_root_intr_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	struct uss820dci_softc *sc = xfer->usb2_sc;
+	struct uss820dci_softc *sc = USS820_DCI_BUS2SC(xfer->xroot->bus);
 
 	DPRINTFN(9, "\n");
 
@@ -1164,7 +1164,7 @@ uss820dci_standard_done(struct usb2_xfer *xfer)
 static void
 uss820dci_device_done(struct usb2_xfer *xfer, usb2_error_t error)
 {
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	DPRINTFN(2, "xfer=%p, pipe=%p, error=%d\n",
 	    xfer, xfer->pipe, error);
@@ -1638,7 +1638,7 @@ uss820dci_device_isoc_fs_close(struct usb2_xfer *xfer)
 static void
 uss820dci_device_isoc_fs_enter(struct usb2_xfer *xfer)
 {
-	struct uss820dci_softc *sc = xfer->usb2_sc;
+	struct uss820dci_softc *sc = USS820_DCI_BUS2SC(xfer->xroot->bus);
 	uint32_t temp;
 	uint32_t nframes;
 
@@ -1720,7 +1720,7 @@ uss820dci_root_ctrl_open(struct usb2_xfer *xfer)
 static void
 uss820dci_root_ctrl_close(struct usb2_xfer *xfer)
 {
-	struct uss820dci_softc *sc = xfer->usb2_sc;
+	struct uss820dci_softc *sc = USS820_DCI_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_ctrl.xfer == xfer) {
 		sc->sc_root_ctrl.xfer = NULL;
@@ -1824,11 +1824,11 @@ uss820dci_root_ctrl_enter(struct usb2_xfer *xfer)
 static void
 uss820dci_root_ctrl_start(struct usb2_xfer *xfer)
 {
-	struct uss820dci_softc *sc = xfer->usb2_sc;
+	struct uss820dci_softc *sc = USS820_DCI_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_root_ctrl.xfer = xfer;
 
-	usb2_bus_roothub_exec(xfer->udev->bus);
+	usb2_bus_roothub_exec(xfer->xroot->bus);
 }
 
 static void
@@ -1841,7 +1841,7 @@ static void
 uss820dci_root_ctrl_done(struct usb2_xfer *xfer,
     struct usb2_sw_transfer *std)
 {
-	struct uss820dci_softc *sc = xfer->usb2_sc;
+	struct uss820dci_softc *sc = USS820_DCI_BUS2SC(xfer->xroot->bus);
 	uint16_t value;
 	uint16_t index;
 	uint8_t use_polling;
@@ -1862,7 +1862,7 @@ uss820dci_root_ctrl_done(struct usb2_xfer *xfer,
 	value = UGETW(std->req.wValue);
 	index = UGETW(std->req.wIndex);
 
-	use_polling = mtx_owned(xfer->xfer_mtx) ? 1 : 0;
+	use_polling = mtx_owned(xfer->xroot->xfer_mtx) ? 1 : 0;
 
 	/* demultiplex the control request */
 
@@ -2258,7 +2258,7 @@ uss820dci_root_intr_open(struct usb2_xfer *xfer)
 static void
 uss820dci_root_intr_close(struct usb2_xfer *xfer)
 {
-	struct uss820dci_softc *sc = xfer->usb2_sc;
+	struct uss820dci_softc *sc = USS820_DCI_BUS2SC(xfer->xroot->bus);
 
 	if (sc->sc_root_intr.xfer == xfer) {
 		sc->sc_root_intr.xfer = NULL;
@@ -2275,7 +2275,7 @@ uss820dci_root_intr_enter(struct usb2_xfer *xfer)
 static void
 uss820dci_root_intr_start(struct usb2_xfer *xfer)
 {
-	struct uss820dci_softc *sc = xfer->usb2_sc;
+	struct uss820dci_softc *sc = USS820_DCI_BUS2SC(xfer->xroot->bus);
 
 	sc->sc_root_intr.xfer = xfer;
 }
@@ -2304,11 +2304,6 @@ uss820dci_xfer_setup(struct usb2_setup_params *parm)
 	sc = USS820_DCI_BUS2SC(parm->udev->bus);
 	xfer = parm->curr_xfer;
 
-	/*
-	 * setup xfer
-	 */
-	xfer->usb2_sc = sc;
-
 	/*
 	 * NOTE: This driver does not use any of the parameters that
 	 * are computed from the following values. Just set some
diff --git a/sys/dev/usb2/core/usb2_busdma.c b/sys/dev/usb2/core/usb2_busdma.c
index be99e00d4abc..6c1f182e34ac 100644
--- a/sys/dev/usb2/core/usb2_busdma.c
+++ b/sys/dev/usb2/core/usb2_busdma.c
@@ -1226,15 +1226,15 @@ usb2_bdma_work_loop(struct usb2_xfer_queue *pq)
 	uint32_t nframes;
 
 	xfer = pq->curr;
-	info = xfer->usb2_root;
+	info = xfer->xroot;
 
-	mtx_assert(info->priv_mtx, MA_OWNED);
+	mtx_assert(info->xfer_mtx, MA_OWNED);
 
 	if (xfer->error) {
 		/* some error happened */
-		USB_BUS_LOCK(xfer->udev->bus);
+		USB_BUS_LOCK(info->bus);
 		usb2_transfer_done(xfer, 0);
-		USB_BUS_UNLOCK(xfer->udev->bus);
+		USB_BUS_UNLOCK(info->bus);
 		return;
 	}
 	if (!xfer->flags_int.bdma_setup) {
@@ -1306,9 +1306,9 @@ usb2_bdma_work_loop(struct usb2_xfer_queue *pq)
 
 	}
 	if (info->dma_error) {
-		USB_BUS_LOCK(xfer->udev->bus);
+		USB_BUS_LOCK(info->bus);
 		usb2_transfer_done(xfer, USB_ERR_DMA_LOAD_FAILED);
-		USB_BUS_UNLOCK(xfer->udev->bus);
+		USB_BUS_UNLOCK(info->bus);
 		return;
 	}
 	if (info->dma_currframe != info->dma_nframes) {
@@ -1352,7 +1352,7 @@ usb2_bdma_done_event(struct usb2_dma_parent_tag *udpt)
 
 	info = udpt->info;
 
-	mtx_assert(info->priv_mtx, MA_OWNED);
+	mtx_assert(info->xfer_mtx, MA_OWNED);
 
 	/* copy error */
 	info->dma_error = udpt->dma_error;
diff --git a/sys/dev/usb2/core/usb2_core.h b/sys/dev/usb2/core/usb2_core.h
index 217ba38698bf..156ec5d29705 100644
--- a/sys/dev/usb2/core/usb2_core.h
+++ b/sys/dev/usb2/core/usb2_core.h
@@ -160,9 +160,9 @@
 #define	USB_BUS_LOCK(_b)		mtx_lock(&(_b)->bus_mtx)
 #define	USB_BUS_UNLOCK(_b)		mtx_unlock(&(_b)->bus_mtx)
 #define	USB_BUS_LOCK_ASSERT(_b, _t)	mtx_assert(&(_b)->bus_mtx, _t)
-#define	USB_XFER_LOCK(_x)		mtx_lock((_x)->xfer_mtx)
-#define	USB_XFER_UNLOCK(_x)		mtx_unlock((_x)->xfer_mtx)
-#define	USB_XFER_LOCK_ASSERT(_x, _t)	mtx_assert((_x)->xfer_mtx, _t)
+#define	USB_XFER_LOCK(_x)		mtx_lock((_x)->xroot->xfer_mtx)
+#define	USB_XFER_UNLOCK(_x)		mtx_unlock((_x)->xroot->xfer_mtx)
+#define	USB_XFER_LOCK_ASSERT(_x, _t)	mtx_assert((_x)->xroot->xfer_mtx, _t)
 /* structure prototypes */
 
 struct file;
@@ -307,10 +307,7 @@ struct usb2_xfer {
 						 * are waiting on */
 	struct usb2_page *dma_page_ptr;
 	struct usb2_pipe *pipe;		/* our USB pipe */
-	struct usb2_device *udev;
-	struct mtx *xfer_mtx;		/* cannot be changed during operation */
-	struct usb2_xfer_root *usb2_root;	/* used by HC driver */
-	void   *usb2_sc;		/* used by HC driver */
+	struct usb2_xfer_root *xroot;	/* used by HC driver */
 	void   *qh_start[2];		/* used by HC driver */
 	void   *td_start[2];		/* used by HC driver */
 	void   *td_transfer_first;	/* used by HC driver */
diff --git a/sys/dev/usb2/core/usb2_debug.c b/sys/dev/usb2/core/usb2_debug.c
index dc9067d1332c..46d27b4eda4e 100644
--- a/sys/dev/usb2/core/usb2_debug.c
+++ b/sys/dev/usb2/core/usb2_debug.c
@@ -31,6 +31,8 @@
 #include <dev/usb2/core/usb2_debug.h>
 #include <dev/usb2/core/usb2_process.h>
 #include <dev/usb2/core/usb2_device.h>
+#include <dev/usb2/core/usb2_busdma.h>
+#include <dev/usb2/core/usb2_transfer.h>
 
 /*
  * Define this unconditionally in case a kernel module is loaded that
@@ -128,6 +130,7 @@ usb2_dump_pipe(struct usb2_pipe *pipe)
 void
 usb2_dump_xfer(struct usb2_xfer *xfer)
 {
+	struct usb2_device *udev;
 	printf("usb2_dump_xfer: xfer=%p\n", xfer);
 	if (xfer == NULL) {
 		return;
@@ -137,12 +140,13 @@ usb2_dump_xfer(struct usb2_xfer *xfer)
 		    xfer);
 		return;
 	}
+	udev = xfer->xroot->udev;
 	printf("xfer %p: udev=%p vid=0x%04x pid=0x%04x addr=%d "
 	    "pipe=%p ep=0x%02x attr=0x%02x\n",
-	    xfer, xfer->udev,
-	    UGETW(xfer->udev->ddesc.idVendor),
-	    UGETW(xfer->udev->ddesc.idProduct),
-	    xfer->udev->address, xfer->pipe,
+	    xfer, udev,
+	    UGETW(udev->ddesc.idVendor),
+	    UGETW(udev->ddesc.idProduct),
+	    udev->address, xfer->pipe,
 	    xfer->pipe->edesc->bEndpointAddress,
 	    xfer->pipe->edesc->bmAttributes);
 }
diff --git a/sys/dev/usb2/core/usb2_handle_request.c b/sys/dev/usb2/core/usb2_handle_request.c
index c7659978b53a..65f0f0187d72 100644
--- a/sys/dev/usb2/core/usb2_handle_request.c
+++ b/sys/dev/usb2/core/usb2_handle_request.c
@@ -86,7 +86,7 @@ usb2_handle_request_callback(struct usb2_xfer *xfer)
 
 			if (err == USB_ERR_BAD_CONTEXT) {
 				/* we need to re-setup the control transfer */
-				usb2_needs_explore(xfer->udev->bus, 0);
+				usb2_needs_explore(xfer->xroot->bus, 0);
 				break;
 			}
 			/*
@@ -126,6 +126,7 @@ usb2_handle_request_callback(struct usb2_xfer *xfer)
 static usb2_error_t
 usb2_handle_set_config(struct usb2_xfer *xfer, uint8_t conf_no)
 {
+	struct usb2_device *udev = xfer->xroot->udev;
 	usb2_error_t err = 0;
 
 	/*
@@ -134,7 +135,7 @@ usb2_handle_set_config(struct usb2_xfer *xfer, uint8_t conf_no)
 	 */
 	USB_XFER_UNLOCK(xfer);
 	mtx_lock(&Giant);		/* XXX */
-	sx_xlock(xfer->udev->default_sx + 1);
+	sx_xlock(udev->default_sx + 1);
 
 	if (conf_no == USB_UNCONFIG_NO) {
 		conf_no = USB_UNCONFIG_INDEX;
@@ -146,19 +147,19 @@ usb2_handle_set_config(struct usb2_xfer *xfer, uint8_t conf_no)
 		conf_no--;
 	}
 
-	if (usb2_set_config_index(xfer->udev, conf_no)) {
+	if (usb2_set_config_index(udev, conf_no)) {
 		DPRINTF("set config %d failed\n", conf_no);
 		err = USB_ERR_STALLED;
 		goto done;
 	}
-	if (usb2_probe_and_attach(xfer->udev, USB_IFACE_INDEX_ANY)) {
+	if (usb2_probe_and_attach(udev, USB_IFACE_INDEX_ANY)) {
 		DPRINTF("probe and attach failed\n");
 		err = USB_ERR_STALLED;
 		goto done;
 	}
 done:
 	mtx_unlock(&Giant);		/* XXX */
-	sx_unlock(xfer->udev->default_sx + 1);
+	sx_unlock(udev->default_sx + 1);
 	USB_XFER_LOCK(xfer);
 	return (err);
 }
@@ -177,7 +178,7 @@ usb2_handle_iface_request(struct usb2_xfer *xfer,
 {
 	struct usb2_interface *iface;
 	struct usb2_interface *iface_parent;	/* parent interface */
-	struct usb2_device *udev = xfer->udev;
+	struct usb2_device *udev = xfer->xroot->udev;
 	int error;
 	uint8_t iface_index;
 
@@ -332,11 +333,12 @@ usb2_handle_iface_request(struct usb2_xfer *xfer,
 static usb2_error_t
 usb2_handle_set_stall(struct usb2_xfer *xfer, uint8_t ep, uint8_t do_stall)
 {
+	struct usb2_device *udev = xfer->xroot->udev;
 	usb2_error_t err;
 
 	USB_XFER_UNLOCK(xfer);
-	err = usb2_set_endpoint_stall(xfer->udev,
-	    usb2_get_pipe_by_addr(xfer->udev, ep), do_stall);
+	err = usb2_set_endpoint_stall(udev,
+	    usb2_get_pipe_by_addr(udev, ep), do_stall);
 	USB_XFER_LOCK(xfer);
 	return (err);
 }
@@ -379,7 +381,7 @@ usb2_handle_remote_wakeup(struct usb2_xfer *xfer, uint8_t is_on)
 	struct usb2_device *udev;
 	struct usb2_bus *bus;
 
-	udev = xfer->udev;
+	udev = xfer->xroot->udev;
 	bus = udev->bus;
 
 	USB_BUS_LOCK(bus);
@@ -479,7 +481,7 @@ usb2_handle_request(struct usb2_xfer *xfer)
 	max_len = 0;
 	src_zcopy = NULL;
 	src_mcopy = NULL;
-	udev = xfer->udev;
+	udev = xfer->xroot->udev;
 
 	/* get some request fields decoded */
 
diff --git a/sys/dev/usb2/core/usb2_hub.c b/sys/dev/usb2/core/usb2_hub.c
index e5c9c8dd903f..cbc1763827a7 100644
--- a/sys/dev/usb2/core/usb2_hub.c
+++ b/sys/dev/usb2/core/usb2_hub.c
@@ -1429,7 +1429,7 @@ usb2_transfer_power_ref(struct usb2_xfer *xfer, int val)
 	uint8_t needs_hw_power;
 	uint8_t xfer_type;
 
-	udev = xfer->udev;
+	udev = xfer->xroot->udev;
 
 	if (udev->device_index == USB_ROOT_HUB_ADDR) {
 		/* no power save for root HUB */
diff --git a/sys/dev/usb2/core/usb2_request.c b/sys/dev/usb2/core/usb2_request.c
index b1eb81fa9b10..3e48dc1ba0c7 100644
--- a/sys/dev/usb2/core/usb2_request.c
+++ b/sys/dev/usb2/core/usb2_request.c
@@ -80,7 +80,7 @@ usb2_do_request_callback(struct usb2_xfer *xfer)
 		usb2_start_hardware(xfer);
 		break;
 	default:
-		usb2_cv_signal(xfer->udev->default_cv);
+		usb2_cv_signal(xfer->xroot->udev->default_cv);
 		break;
 	}
 }
@@ -94,18 +94,21 @@ void
 usb2_do_clear_stall_callback(struct usb2_xfer *xfer)
 {
 	struct usb2_device_request req;
+	struct usb2_device *udev;
 	struct usb2_pipe *pipe;
 	struct usb2_pipe *pipe_end;
 	struct usb2_pipe *pipe_first;
 	uint8_t to = USB_EP_MAX;
 
-	USB_BUS_LOCK(xfer->udev->bus);
+	udev = xfer->xroot->udev;
+
+	USB_BUS_LOCK(udev->bus);
 
 	/* round robin pipe clear stall */
 
-	pipe = xfer->udev->pipe_curr;
-	pipe_end = xfer->udev->pipes + USB_EP_MAX;
-	pipe_first = xfer->udev->pipes;
+	pipe = udev->pipe_curr;
+	pipe_end = udev->pipes + USB_EP_MAX;
+	pipe_first = udev->pipes;
 	if (pipe == NULL) {
 		pipe = pipe_first;
 	}
@@ -145,11 +148,11 @@ usb2_do_clear_stall_callback(struct usb2_xfer *xfer)
 			/* set length */
 			xfer->frlengths[0] = sizeof(req);
 			xfer->nframes = 1;
-			USB_BUS_UNLOCK(xfer->udev->bus);
+			USB_BUS_UNLOCK(udev->bus);
 
 			usb2_start_hardware(xfer);
 
-			USB_BUS_LOCK(xfer->udev->bus);
+			USB_BUS_LOCK(udev->bus);
 			break;
 		}
 		pipe++;
@@ -165,8 +168,8 @@ usb2_do_clear_stall_callback(struct usb2_xfer *xfer)
 	}
 
 	/* store current pipe */
-	xfer->udev->pipe_curr = pipe;
-	USB_BUS_UNLOCK(xfer->udev->bus);
+	udev->pipe_curr = pipe;
+	USB_BUS_UNLOCK(udev->bus);
 }
 
 /*------------------------------------------------------------------------*
@@ -367,7 +370,8 @@ usb2_do_request_flags(struct usb2_device *udev, struct mtx *mtx,
 					}
 					if (temp > 0) {
 						usb2_pause_mtx(
-						    xfer->xfer_mtx, temp);
+						    xfer->xroot->xfer_mtx,
+						    temp);
 					}
 #endif
 					xfer->flags.manual_status = 0;
@@ -384,8 +388,8 @@ usb2_do_request_flags(struct usb2_device *udev, struct mtx *mtx,
 			if ((flags & USB_USE_POLLING) || cold) {
 				usb2_do_poll(udev->default_xfer, USB_DEFAULT_XFER_MAX);
 			} else {
-				usb2_cv_wait(xfer->udev->default_cv,
-				    xfer->xfer_mtx);
+				usb2_cv_wait(udev->default_cv,
+				    xfer->xroot->xfer_mtx);
 			}
 		}
 
diff --git a/sys/dev/usb2/core/usb2_transfer.c b/sys/dev/usb2/core/usb2_transfer.c
index c415b88d9ca4..2237c7ec286d 100644
--- a/sys/dev/usb2/core/usb2_transfer.c
+++ b/sys/dev/usb2/core/usb2_transfer.c
@@ -243,12 +243,12 @@ usb2_transfer_setup_sub_malloc(struct usb2_setup_params *parm,
 	for (x = 0; x != n_dma_pc; x++) {
 		/* need to initialize the page cache */
 		parm->dma_page_cache_ptr[x].tag_parent =
-		    &parm->curr_xfer->usb2_root->dma_parent_tag;
+		    &parm->curr_xfer->xroot->dma_parent_tag;
 	}
 	for (x = 0; x != count; x++) {
 		/* need to initialize the page cache */
 		parm->xfer_page_cache_ptr[x].tag_parent =
-		    &parm->curr_xfer->usb2_root->dma_parent_tag;
+		    &parm->curr_xfer->xroot->dma_parent_tag;
 	}
 
 	if (ppc) {
@@ -670,7 +670,7 @@ usb2_transfer_setup_sub(struct usb2_setup_params *parm)
 	if (parm->buf) {
 		for (x = 0; x != n_frbuffers; x++) {
 			xfer->frbuffers[x].tag_parent =
-			    &xfer->usb2_root->dma_parent_tag;
+			    &xfer->xroot->dma_parent_tag;
 
 			if (xfer->flags_int.bdma_enable &&
 			    (parm->bufsize_max > 0)) {
@@ -715,7 +715,7 @@ usb2_error_t
 usb2_transfer_setup(struct usb2_device *udev,
     const uint8_t *ifaces, struct usb2_xfer **ppxfer,
     const struct usb2_config *setup_start, uint16_t n_setup,
-    void *priv_sc, struct mtx *priv_mtx)
+    void *priv_sc, struct mtx *xfer_mtx)
 {
 	struct usb2_xfer dummy;
 	struct usb2_setup_params parm;
@@ -745,9 +745,9 @@ usb2_transfer_setup(struct usb2_device *udev,
 		DPRINTFN(6, "ifaces array is NULL!\n");
 		return (USB_ERR_INVAL);
 	}
-	if (priv_mtx == NULL) {
+	if (xfer_mtx == NULL) {
 		DPRINTFN(6, "using global lock\n");
-		priv_mtx = &Giant;
+		xfer_mtx = &Giant;
 	}
 	/* sanity checks */
 	for (setup = setup_start, n = 0;
@@ -799,13 +799,14 @@ usb2_transfer_setup(struct usb2_device *udev,
 
 			usb2_cv_init(&info->cv_drain, "WDRAIN");
 
-			info->priv_mtx = priv_mtx;
+			info->xfer_mtx = xfer_mtx;
 
 			usb2_dma_tag_setup(&info->dma_parent_tag,
 			    parm.dma_tag_p, udev->bus->dma_parent_tag[0].tag,
-			    priv_mtx, &usb2_bdma_done_event, info, 32, parm.dma_tag_max);
+			    xfer_mtx, &usb2_bdma_done_event, info, 32, parm.dma_tag_max);
 
 			info->bus = udev->bus;
+			info->udev = udev;
 
 			TAILQ_INIT(&info->done_q.head);
 			info->done_q.command = &usb2_callback_wrapper;
@@ -814,9 +815,9 @@ usb2_transfer_setup(struct usb2_device *udev,
 			info->dma_q.command = &usb2_bdma_work_loop;
 
 			info->done_m[0].hdr.pm_callback = &usb2_callback_proc;
-			info->done_m[0].usb2_root = info;
+			info->done_m[0].xroot = info;
 			info->done_m[1].hdr.pm_callback = &usb2_callback_proc;
-			info->done_m[1].usb2_root = info;
+			info->done_m[1].xroot = info;
 
 			/* create a callback thread */
 
@@ -871,11 +872,9 @@ usb2_transfer_setup(struct usb2_device *udev,
 				xfer = USB_ADD_BYTES(buf, parm.size[0]);
 
 				ppxfer[n] = xfer;
-				xfer->udev = udev;
 				xfer->address = udev->address;
 				xfer->priv_sc = priv_sc;
-				xfer->xfer_mtx = priv_mtx;
-				xfer->usb2_root = info;
+				xfer->xroot = info;
 				info->setup_refcount++;
 
 				usb2_callout_init_mtx(&xfer->timeout_handle,
@@ -1100,7 +1099,7 @@ usb2_transfer_unsetup(struct usb2_xfer **pxfer, uint16_t n_setup)
 		if (xfer) {
 			if (xfer->pipe) {
 				USB_XFER_LOCK(xfer);
-				USB_BUS_LOCK(xfer->udev->bus);
+				USB_BUS_LOCK(xfer->xroot->bus);
 
 				/*
 				 * HINT: when you start/stop a transfer, it
@@ -1112,7 +1111,7 @@ usb2_transfer_unsetup(struct usb2_xfer **pxfer, uint16_t n_setup)
 				 *
 				 * That way, if your code has many parts that
 				 * will not stop running under the same
-				 * lock, in other words "priv_mtx", the
+				 * lock, in other words "xfer_mtx", the
 				 * usb2_transfer_start and
 				 * usb2_transfer_stop functions will simply
 				 * return when they detect a NULL pointer
@@ -1124,7 +1123,7 @@ usb2_transfer_unsetup(struct usb2_xfer **pxfer, uint16_t n_setup)
 				 */
 				pxfer[n_setup] = NULL;
 
-				USB_BUS_UNLOCK(xfer->udev->bus);
+				USB_BUS_UNLOCK(xfer->xroot->bus);
 				USB_XFER_UNLOCK(xfer);
 
 				usb2_transfer_drain(xfer);
@@ -1145,8 +1144,8 @@ usb2_transfer_unsetup(struct usb2_xfer **pxfer, uint16_t n_setup)
 
 			usb2_callout_drain(&xfer->timeout_handle);
 
-			if (xfer->usb2_root) {
-				info = xfer->usb2_root;
+			if (xfer->xroot) {
+				info = xfer->xroot;
 
 				USB_BUS_LOCK(info->bus);
 
@@ -1349,16 +1348,16 @@ usb2_start_hardware(struct usb2_xfer *xfer)
 
 #if USB_DEBUG
 	if (USB_DEBUG_VAR > 0) {
-		USB_BUS_LOCK(xfer->udev->bus);
+		USB_BUS_LOCK(xfer->xroot->bus);
 
 		usb2_dump_pipe(xfer->pipe);
 
-		USB_BUS_UNLOCK(xfer->udev->bus);
+		USB_BUS_UNLOCK(xfer->xroot->bus);
 	}
 #endif
 
 	USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_NOTOWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_NOTOWNED);
 
 	/* Only open the USB transfer once! */
 	if (!xfer->flags_int.open) {
@@ -1366,9 +1365,9 @@ usb2_start_hardware(struct usb2_xfer *xfer)
 
 		DPRINTF("open\n");
 
-		USB_BUS_LOCK(xfer->udev->bus);
+		USB_BUS_LOCK(xfer->xroot->bus);
 		(xfer->pipe->methods->open) (xfer);
-		USB_BUS_UNLOCK(xfer->udev->bus);
+		USB_BUS_UNLOCK(xfer->xroot->bus);
 	}
 	/* set "transferring" flag */
 	xfer->flags_int.transferring = 1;
@@ -1381,9 +1380,9 @@ usb2_start_hardware(struct usb2_xfer *xfer)
 	 * frequently the "done_q":
 	 */
 	if (xfer->wait_queue) {
-		USB_BUS_LOCK(xfer->udev->bus);
+		USB_BUS_LOCK(xfer->xroot->bus);
 		usb2_transfer_dequeue(xfer);
-		USB_BUS_UNLOCK(xfer->udev->bus);
+		USB_BUS_UNLOCK(xfer->xroot->bus);
 	}
 	/* clear "did_dma_delay" flag */
 	xfer->flags_int.did_dma_delay = 0;
@@ -1415,16 +1414,16 @@ usb2_start_hardware(struct usb2_xfer *xfer)
 			 */
 			DPRINTF("xfer=%p nframes=0: stall "
 			    "or clear stall!\n", xfer);
-			USB_BUS_LOCK(xfer->udev->bus);
+			USB_BUS_LOCK(xfer->xroot->bus);
 			xfer->flags_int.can_cancel_immed = 1;
 			/* start the transfer */
 			usb2_command_wrapper(&xfer->pipe->pipe_q, xfer);
-			USB_BUS_UNLOCK(xfer->udev->bus);
+			USB_BUS_UNLOCK(xfer->xroot->bus);
 			return;
 		}
-		USB_BUS_LOCK(xfer->udev->bus);
+		USB_BUS_LOCK(xfer->xroot->bus);
 		usb2_transfer_done(xfer, USB_ERR_INVAL);
-		USB_BUS_UNLOCK(xfer->udev->bus);
+		USB_BUS_UNLOCK(xfer->xroot->bus);
 		return;
 	}
 	/* compute total transfer length */
@@ -1433,9 +1432,9 @@ usb2_start_hardware(struct usb2_xfer *xfer)
 		xfer->sumlen += xfer->frlengths[x];
 		if (xfer->sumlen < xfer->frlengths[x]) {
 			/* length wrapped around */
-			USB_BUS_LOCK(xfer->udev->bus);
+			USB_BUS_LOCK(xfer->xroot->bus);
 			usb2_transfer_done(xfer, USB_ERR_INVAL);
-			USB_BUS_UNLOCK(xfer->udev->bus);
+			USB_BUS_UNLOCK(xfer->xroot->bus);
 			return;
 		}
 	}
@@ -1450,9 +1449,9 @@ usb2_start_hardware(struct usb2_xfer *xfer)
 	if (xfer->flags_int.control_xfr) {
 
 		if (usb2_start_hardware_sub(xfer)) {
-			USB_BUS_LOCK(xfer->udev->bus);
+			USB_BUS_LOCK(xfer->xroot->bus);
 			usb2_transfer_done(xfer, USB_ERR_STALLED);
-			USB_BUS_UNLOCK(xfer->udev->bus);
+			USB_BUS_UNLOCK(xfer->xroot->bus);
 			return;
 		}
 	}
@@ -1488,7 +1487,7 @@ usb2_start_hardware(struct usb2_xfer *xfer)
 	 */
 	if (xfer->flags_int.bdma_enable) {
 		/* insert the USB transfer last in the BUS-DMA queue */
-		usb2_command_wrapper(&xfer->usb2_root->dma_q, xfer);
+		usb2_command_wrapper(&xfer->xroot->dma_q, xfer);
 		return;
 	}
 	/*
@@ -1508,7 +1507,7 @@ usb2_pipe_enter(struct usb2_xfer *xfer)
 
 	USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);
 
-	USB_BUS_LOCK(xfer->udev->bus);
+	USB_BUS_LOCK(xfer->xroot->bus);
 
 	pipe = xfer->pipe;
 
@@ -1524,7 +1523,7 @@ usb2_pipe_enter(struct usb2_xfer *xfer)
 		if (xfer->error) {
 			/* some error has happened */
 			usb2_transfer_done(xfer, 0);
-			USB_BUS_UNLOCK(xfer->udev->bus);
+			USB_BUS_UNLOCK(xfer->xroot->bus);
 			return;
 		}
 	} else {
@@ -1533,7 +1532,7 @@ usb2_pipe_enter(struct usb2_xfer *xfer)
 
 	/* start the transfer */
 	usb2_command_wrapper(&pipe->pipe_q, xfer);
-	USB_BUS_UNLOCK(xfer->udev->bus);
+	USB_BUS_UNLOCK(xfer->xroot->bus);
 }
 
 /*------------------------------------------------------------------------*
@@ -1562,10 +1561,10 @@ usb2_transfer_start(struct usb2_xfer *xfer)
 	if (xfer->flags_int.transferring) {
 		return;
 	}
-	USB_BUS_LOCK(xfer->udev->bus);
+	USB_BUS_LOCK(xfer->xroot->bus);
 	/* call the USB transfer callback */
 	usb2_callback_ss_done_defer(xfer);
-	USB_BUS_UNLOCK(xfer->udev->bus);
+	USB_BUS_UNLOCK(xfer->xroot->bus);
 }
 
 /*------------------------------------------------------------------------*
@@ -1596,7 +1595,7 @@ usb2_transfer_stop(struct usb2_xfer *xfer)
 	}
 	/* try to stop the current USB transfer */
 
-	USB_BUS_LOCK(xfer->udev->bus);
+	USB_BUS_LOCK(xfer->xroot->bus);
 	xfer->error = USB_ERR_CANCELLED;/* override any previous error */
 	/*
 	 * Clear "open" and "started" when both private and USB lock
@@ -1648,7 +1647,7 @@ usb2_transfer_stop(struct usb2_xfer *xfer)
 		}
 	}
 
-	USB_BUS_UNLOCK(xfer->udev->bus);
+	USB_BUS_UNLOCK(xfer->xroot->bus);
 }
 
 /*------------------------------------------------------------------------*
@@ -1672,22 +1671,22 @@ usb2_transfer_pending(struct usb2_xfer *xfer)
 		/* trivial case */
 		return (1);
 	}
-	USB_BUS_LOCK(xfer->udev->bus);
+	USB_BUS_LOCK(xfer->xroot->bus);
 	if (xfer->wait_queue) {
 		/* we are waiting on a queue somewhere */
-		USB_BUS_UNLOCK(xfer->udev->bus);
+		USB_BUS_UNLOCK(xfer->xroot->bus);
 		return (1);
 	}
-	info = xfer->usb2_root;
+	info = xfer->xroot;
 	pq = &info->done_q;
 
 	if (pq->curr == xfer) {
 		/* we are currently scheduled for callback */
-		USB_BUS_UNLOCK(xfer->udev->bus);
+		USB_BUS_UNLOCK(xfer->xroot->bus);
 		return (1);
 	}
 	/* we are not pending */
-	USB_BUS_UNLOCK(xfer->udev->bus);
+	USB_BUS_UNLOCK(xfer->xroot->bus);
 	return (0);
 }
 
@@ -1709,7 +1708,7 @@ usb2_transfer_drain(struct usb2_xfer *xfer)
 		/* transfer is gone */
 		return;
 	}
-	if (xfer->xfer_mtx != &Giant) {
+	if (xfer->xroot->xfer_mtx != &Giant) {
 		USB_XFER_LOCK_ASSERT(xfer, MA_NOTOWNED);
 	}
 	USB_XFER_LOCK(xfer);
@@ -1722,7 +1721,7 @@ usb2_transfer_drain(struct usb2_xfer *xfer)
 		 * Wait until the current outstanding USB
 		 * transfer is complete !
 		 */
-		usb2_cv_wait(&xfer->usb2_root->cv_drain, xfer->xfer_mtx);
+		usb2_cv_wait(&xfer->xroot->cv_drain, xfer->xroot->xfer_mtx);
 	}
 	USB_XFER_UNLOCK(xfer);
 }
@@ -1769,7 +1768,7 @@ static void
 usb2_callback_proc(struct usb2_proc_msg *_pm)
 {
 	struct usb2_done_msg *pm = (void *)_pm;
-	struct usb2_xfer_root *info = pm->usb2_root;
+	struct usb2_xfer_root *info = pm->xroot;
 
 	/* Change locking order */
 	USB_BUS_UNLOCK(info->bus);
@@ -1778,14 +1777,14 @@ usb2_callback_proc(struct usb2_proc_msg *_pm)
 	 * We exploit the fact that the mutex is the same for all
 	 * callbacks that will be called from this thread:
 	 */
-	mtx_lock(info->priv_mtx);
+	mtx_lock(info->xfer_mtx);
 	USB_BUS_LOCK(info->bus);
 
 	/* Continue where we lost track */
 	usb2_command_wrapper(&info->done_q,
 	    info->done_q.curr);
 
-	mtx_unlock(info->priv_mtx);
+	mtx_unlock(info->xfer_mtx);
 }
 
 /*------------------------------------------------------------------------*
@@ -1797,10 +1796,10 @@ usb2_callback_proc(struct usb2_proc_msg *_pm)
 static void
 usb2_callback_ss_done_defer(struct usb2_xfer *xfer)
 {
-	struct usb2_xfer_root *info = xfer->usb2_root;
+	struct usb2_xfer_root *info = xfer->xroot;
 	struct usb2_xfer_queue *pq = &info->done_q;
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	if (pq->curr != xfer) {
 		usb2_transfer_enqueue(pq, xfer);
@@ -1836,10 +1835,10 @@ static void
 usb2_callback_wrapper(struct usb2_xfer_queue *pq)
 {
 	struct usb2_xfer *xfer = pq->curr;
-	struct usb2_xfer_root *info = xfer->usb2_root;
+	struct usb2_xfer_root *info = xfer->xroot;
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
-	if (!mtx_owned(xfer->xfer_mtx)) {
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
+	if (!mtx_owned(xfer->xroot->xfer_mtx)) {
 		/*
 	       	 * Cases that end up here:
 		 *
@@ -1870,22 +1869,22 @@ usb2_callback_wrapper(struct usb2_xfer_queue *pq)
 	/* get next USB transfer in the queue */
 	info->done_q.curr = NULL;
 
-	USB_BUS_UNLOCK(xfer->udev->bus);
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_NOTOWNED);
+	USB_BUS_UNLOCK(xfer->xroot->bus);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_NOTOWNED);
 
 	/* set correct USB state for callback */
 	if (!xfer->flags_int.transferring) {
 		xfer->usb2_state = USB_ST_SETUP;
 		if (!xfer->flags_int.started) {
 			/* we got stopped before we even got started */
-			USB_BUS_LOCK(xfer->udev->bus);
+			USB_BUS_LOCK(xfer->xroot->bus);
 			goto done;
 		}
 	} else {
 
 		if (usb2_callback_wrapper_sub(xfer)) {
 			/* the callback has been deferred */
-			USB_BUS_LOCK(xfer->udev->bus);
+			USB_BUS_LOCK(xfer->xroot->bus);
 			goto done;
 		}
 		/* decrement power reference */
@@ -1911,7 +1910,7 @@ usb2_callback_wrapper(struct usb2_xfer_queue *pq)
 	(xfer->callback) (xfer);
 
 	/* pickup the USB mutex again */
-	USB_BUS_LOCK(xfer->udev->bus);
+	USB_BUS_LOCK(xfer->xroot->bus);
 
 	/*
 	 * Check if we got started after that we got cancelled, but
@@ -1933,7 +1932,7 @@ usb2_callback_wrapper(struct usb2_xfer_queue *pq)
 	    (!xfer->flags_int.transferring)) {
 		/* "usb2_transfer_drain()" is waiting for end of transfer */
 		xfer->flags_int.draining = 0;
-		usb2_cv_broadcast(&xfer->usb2_root->cv_drain);
+		usb2_cv_broadcast(&xfer->xroot->cv_drain);
 	}
 
 	/* do the next callback, if any */
@@ -1954,7 +1953,7 @@ usb2_dma_delay_done_cb(void *arg)
 {
 	struct usb2_xfer *xfer = arg;
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	DPRINTFN(3, "Completed %p\n", xfer);
 
@@ -2019,7 +2018,7 @@ usb2_transfer_done(struct usb2_xfer *xfer, usb2_error_t error)
 {
 	struct usb2_xfer_queue *pq;
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	DPRINTF("err=%s\n", usb2_errstr(error));
 
@@ -2045,12 +2044,12 @@ usb2_transfer_done(struct usb2_xfer *xfer, usb2_error_t error)
 	 */
 	usb2_transfer_dequeue(xfer);
 
-	if (mtx_owned(xfer->xfer_mtx)) {
+	if (mtx_owned(xfer->xroot->xfer_mtx)) {
 		/*
 		 * If the private USB lock is not locked, then we assume
 		 * that the BUS-DMA load stage has been passed:
 		 */
-		pq = &xfer->usb2_root->dma_q;
+		pq = &xfer->xroot->dma_q;
 
 		if (pq->curr == xfer) {
 			/* start the next BUS-DMA load, if any */
@@ -2059,10 +2058,10 @@ usb2_transfer_done(struct usb2_xfer *xfer, usb2_error_t error)
 	}
 	/* keep some statistics */
 	if (xfer->error) {
-		xfer->udev->bus->stats_err.uds_requests
+		xfer->xroot->bus->stats_err.uds_requests
 		    [xfer->pipe->edesc->bmAttributes & UE_XFERTYPE]++;
 	} else {
-		xfer->udev->bus->stats_ok.uds_requests
+		xfer->xroot->bus->stats_ok.uds_requests
 		    [xfer->pipe->edesc->bmAttributes & UE_XFERTYPE]++;
 	}
 
@@ -2083,7 +2082,7 @@ usb2_transfer_start_cb(void *arg)
 	struct usb2_xfer *xfer = arg;
 	struct usb2_pipe *pipe = xfer->pipe;
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	DPRINTF("start\n");
 
@@ -2118,11 +2117,11 @@ usb2_transfer_set_stall(struct usb2_xfer *xfer)
 	USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);
 
 	/* avoid any races by locking the USB mutex */
-	USB_BUS_LOCK(xfer->udev->bus);
+	USB_BUS_LOCK(xfer->xroot->bus);
 
 	xfer->flags.stall_pipe = 1;
 
-	USB_BUS_UNLOCK(xfer->udev->bus);
+	USB_BUS_UNLOCK(xfer->xroot->bus);
 }
 
 /*------------------------------------------------------------------------*
@@ -2141,11 +2140,11 @@ usb2_transfer_clear_stall(struct usb2_xfer *xfer)
 	USB_XFER_LOCK_ASSERT(xfer, MA_OWNED);
 
 	/* avoid any races by locking the USB mutex */
-	USB_BUS_LOCK(xfer->udev->bus);
+	USB_BUS_LOCK(xfer->xroot->bus);
 
 	xfer->flags.stall_pipe = 0;
 
-	USB_BUS_UNLOCK(xfer->udev->bus);
+	USB_BUS_UNLOCK(xfer->xroot->bus);
 }
 
 /*------------------------------------------------------------------------*
@@ -2163,7 +2162,7 @@ usb2_pipe_start(struct usb2_xfer_queue *pq)
 	xfer = pq->curr;
 	pipe = xfer->pipe;
 
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	/*
 	 * If the pipe is already stalled we do nothing !
@@ -2187,14 +2186,15 @@ usb2_pipe_start(struct usb2_xfer_queue *pq)
 			struct usb2_device *udev;
 			struct usb2_xfer_root *info;
 
-			udev = xfer->udev;
+			info = xfer->xroot;
+			udev = info->udev;
 			pipe->is_stalled = 1;
 
 			if (udev->flags.usb2_mode == USB_MODE_DEVICE) {
 				(udev->bus->methods->set_stall) (
 				    udev, NULL, pipe);
 			} else if (udev->default_xfer[1]) {
-				info = udev->default_xfer[1]->usb2_root;
+				info = udev->default_xfer[1]->xroot;
 				if (usb2_proc_msignal(&info->done_p,
 				    &udev->cs_msg[0], &udev->cs_msg[1])) {
 					/* ignore */
@@ -2265,7 +2265,7 @@ void
 usb2_transfer_timeout_ms(struct usb2_xfer *xfer,
     void (*cb) (void *arg), uint32_t ms)
 {
-	USB_BUS_LOCK_ASSERT(xfer->udev->bus, MA_OWNED);
+	USB_BUS_LOCK_ASSERT(xfer->xroot->bus, MA_OWNED);
 
 	/* defer delay */
 	usb2_callout_reset(&xfer->timeout_handle,
@@ -2298,9 +2298,9 @@ usb2_callback_wrapper_sub(struct usb2_xfer *xfer)
 	if ((!xfer->flags_int.open) &&
 	    (!xfer->flags_int.did_close)) {
 		DPRINTF("close\n");
-		USB_BUS_LOCK(xfer->udev->bus);
+		USB_BUS_LOCK(xfer->xroot->bus);
 		(xfer->pipe->methods->close) (xfer);
-		USB_BUS_UNLOCK(xfer->udev->bus);
+		USB_BUS_UNLOCK(xfer->xroot->bus);
 		/* only close once */
 		xfer->flags_int.did_close = 1;
 		return (1);		/* wait for new callback */
@@ -2321,16 +2321,16 @@ usb2_callback_wrapper_sub(struct usb2_xfer *xfer)
 		/* we can not cancel this delay */
 		xfer->flags_int.can_cancel_immed = 0;
 
-		temp = usb2_get_dma_delay(xfer->udev->bus);
+		temp = usb2_get_dma_delay(xfer->xroot->bus);
 
 		DPRINTFN(3, "DMA delay, %u ms, "
 		    "on %p\n", temp, xfer);
 
 		if (temp != 0) {
-			USB_BUS_LOCK(xfer->udev->bus);
+			USB_BUS_LOCK(xfer->xroot->bus);
 			usb2_transfer_timeout_ms(xfer,
 			    &usb2_dma_delay_done_cb, temp);
-			USB_BUS_UNLOCK(xfer->udev->bus);
+			USB_BUS_UNLOCK(xfer->xroot->bus);
 			return (1);	/* wait for new callback */
 		}
 	}
@@ -2422,7 +2422,7 @@ usb2_callback_wrapper_sub(struct usb2_xfer *xfer)
 	 * If the current USB transfer is completing we need to start the
 	 * next one:
 	 */
-	USB_BUS_LOCK(xfer->udev->bus);
+	USB_BUS_LOCK(xfer->xroot->bus);
 	if (pipe->pipe_q.curr == xfer) {
 		usb2_command_wrapper(&pipe->pipe_q, NULL);
 
@@ -2434,7 +2434,7 @@ usb2_callback_wrapper_sub(struct usb2_xfer *xfer)
 			xfer->pipe->is_synced = 0;
 		}
 	}
-	USB_BUS_UNLOCK(xfer->udev->bus);
+	USB_BUS_UNLOCK(xfer->xroot->bus);
 done:
 	return (0);
 }
@@ -2637,7 +2637,7 @@ usb2_clear_stall_callback(struct usb2_xfer *xfer1,
 		 * "ata-usb.c" depends on this)
 		 */
 
-		usb2_clear_data_toggle(xfer2->udev, xfer2->pipe);
+		usb2_clear_data_toggle(xfer2->xroot->udev, xfer2->pipe);
 
 		/* setup a clear-stall packet */
 
@@ -2730,7 +2730,7 @@ void
 usb2_do_poll(struct usb2_xfer **ppxfer, uint16_t max)
 {
 	struct usb2_xfer *xfer;
-	struct usb2_xfer_root *usb2_root;
+	struct usb2_xfer_root *xroot;
 	struct usb2_device *udev;
 	struct usb2_proc_msg *pm;
 	uint32_t to;
@@ -2744,8 +2744,8 @@ usb2_do_poll(struct usb2_xfer **ppxfer, uint16_t max)
 	for (n = 0; n != max; n++) {
 		xfer = ppxfer[n];
 		if (xfer) {
-			usb2_root = xfer->usb2_root;
-			udev = xfer->udev;
+			xroot = xfer->xroot;
+			udev = xroot->udev;
 
 			/*
 			 * Poll hardware - signal that we are polling by
@@ -2756,10 +2756,10 @@ usb2_do_poll(struct usb2_xfer **ppxfer, uint16_t max)
 			USB_XFER_UNLOCK(xfer);
 
 			/* poll clear stall start */
-			USB_BUS_LOCK(xfer->udev->bus);
+			USB_BUS_LOCK(xfer->xroot->bus);
 			pm = &udev->cs_msg[0].hdr;
 			(pm->pm_callback) (pm);
-			USB_BUS_UNLOCK(xfer->udev->bus);
+			USB_BUS_UNLOCK(xfer->xroot->bus);
 
 			if (udev->default_xfer[1]) {
 
@@ -2767,20 +2767,20 @@ usb2_do_poll(struct usb2_xfer **ppxfer, uint16_t max)
 				usb2_callout_poll(udev->default_xfer[1]);
 
 				/* poll clear stall done thread */
-				USB_BUS_LOCK(xfer->udev->bus);
+				USB_BUS_LOCK(xfer->xroot->bus);
 				pm = &udev->default_xfer[1]->
-				    usb2_root->done_m[0].hdr;
+				    xroot->done_m[0].hdr;
 				(pm->pm_callback) (pm);
-				USB_BUS_UNLOCK(xfer->udev->bus);
+				USB_BUS_UNLOCK(xfer->xroot->bus);
 			}
 			/* poll timeout */
 			usb2_callout_poll(xfer);
 
 			/* poll done thread */
-			USB_BUS_LOCK(xfer->udev->bus);
-			pm = &usb2_root->done_m[0].hdr;
+			USB_BUS_LOCK(xfer->xroot->bus);
+			pm = &xroot->done_m[0].hdr;
 			(pm->pm_callback) (pm);
-			USB_BUS_UNLOCK(xfer->udev->bus);
+			USB_BUS_UNLOCK(xfer->xroot->bus);
 		}
 	}
 }
diff --git a/sys/dev/usb2/core/usb2_transfer.h b/sys/dev/usb2/core/usb2_transfer.h
index 698509c5e061..7e95be1a83f8 100644
--- a/sys/dev/usb2/core/usb2_transfer.h
+++ b/sys/dev/usb2/core/usb2_transfer.h
@@ -33,7 +33,7 @@
  */
 struct usb2_done_msg {
 	struct usb2_proc_msg hdr;
-	struct usb2_xfer_root *usb2_root;
+	struct usb2_xfer_root *xroot;
 };
 
 /*
@@ -46,17 +46,17 @@ struct usb2_xfer_root {
 	struct usb2_xfer_queue done_q;
 	struct usb2_done_msg done_m[2];
 	struct cv cv_drain;
-
 	struct usb2_dma_parent_tag dma_parent_tag;
-
 	struct usb2_process done_p;
+
 	void   *memory_base;
-	struct mtx *priv_mtx;
+	struct mtx *xfer_mtx;	/* cannot be changed during operation */
 	struct usb2_page_cache *dma_page_cache_start;
 	struct usb2_page_cache *dma_page_cache_end;
 	struct usb2_page_cache *xfer_page_cache_start;
 	struct usb2_page_cache *xfer_page_cache_end;
-	struct usb2_bus *bus;
+	struct usb2_bus *bus;		/* pointer to USB bus (cached) */
+	struct usb2_device *udev;	/* pointer to USB device */
 
 	uint32_t memory_size;
 	uint32_t setup_refcount;
diff --git a/sys/dev/usb2/serial/uvscom2.c b/sys/dev/usb2/serial/uvscom2.c
index 92577d42b770..7f92c543f86f 100644
--- a/sys/dev/usb2/serial/uvscom2.c
+++ b/sys/dev/usb2/serial/uvscom2.c
@@ -339,9 +339,9 @@ uvscom_attach(device_t dev)
 		goto detach;
 	}
 	/* start interrupt pipe */
-	USB_XFER_LOCK(sc->sc_xfer[4]);
+	mtx_lock(&Giant);
 	usb2_transfer_start(sc->sc_xfer[4]);
-	USB_XFER_UNLOCK(sc->sc_xfer[4]);
+	mtx_unlock(&Giant);
 
 	return (0);
 
diff --git a/sys/dev/usb2/storage/ata-usb2.c b/sys/dev/usb2/storage/ata-usb2.c
index 98bb4dac9e78..f72ac9ffe5c1 100644
--- a/sys/dev/usb2/storage/ata-usb2.c
+++ b/sys/dev/usb2/storage/ata-usb2.c
@@ -773,11 +773,12 @@ atausb2_t_bbb_status_callback(struct usb2_xfer *xfer)
 
 		sc->ata_request = NULL;
 
-		USB_XFER_UNLOCK(xfer);
+		/* drop the USB transfer lock while doing the ATA interrupt */
+		mtx_unlock(&sc->locked_mtx);
 
 		ata_interrupt(device_get_softc(request->parent));
 
-		USB_XFER_LOCK(xfer);
+		mtx_lock(&sc->locked_mtx);
 		return;
 
 	case USB_ST_SETUP: