Index: sys/dev/usb/umass.c
===================================================================
RCS file: /cvsroot/src/sys/dev/usb/umass.c,v
retrieving revision 1.156
diff -u -p -r1.156 umass.c
--- sys/dev/usb/umass.c	7 Jul 2016 06:55:42 -0000	1.156
+++ sys/dev/usb/umass.c	19 Nov 2016 12:27:34 -0000
@@ -527,8 +527,7 @@ umass_attach(device_t parent, device_t s
 	DPRINTFM(UDMASS_USB, "sc %p: opening iface %p epaddr %d for BULKOUT",
 	    sc, sc->sc_iface, sc->sc_epaddr[UMASS_BULKOUT], 0);
 	err = usbd_open_pipe(sc->sc_iface, sc->sc_epaddr[UMASS_BULKOUT],
-				USBD_EXCLUSIVE_USE,
-				&sc->sc_pipe[UMASS_BULKOUT]);
+	    USBD_EXCLUSIVE_USE | USBD_MPSAFE, &sc->sc_pipe[UMASS_BULKOUT]);
 	if (err) {
 		aprint_error_dev(self, "cannot open %u-out pipe (bulk)\n",
 		    sc->sc_epaddr[UMASS_BULKOUT]);
@@ -538,7 +537,7 @@ umass_attach(device_t parent, device_t s
 	DPRINTFM(UDMASS_USB, "sc %p: opening iface %p epaddr %d for BULKIN",
 	    sc, sc->sc_iface, sc->sc_epaddr[UMASS_BULKIN], 0);
 	err = usbd_open_pipe(sc->sc_iface, sc->sc_epaddr[UMASS_BULKIN],
-	    USBD_EXCLUSIVE_USE, &sc->sc_pipe[UMASS_BULKIN]);
+	    USBD_EXCLUSIVE_USE | USBD_MPSAFE, &sc->sc_pipe[UMASS_BULKIN]);
 	if (err) {
 		aprint_error_dev(self, "could not open %u-in pipe (bulk)\n",
 		    sc->sc_epaddr[UMASS_BULKIN]);
@@ -562,7 +561,7 @@ umass_attach(device_t parent, device_t s
 		    "sc %p: opening iface %p epaddr %d for INTRIN",
 		    sc, sc->sc_iface, sc->sc_epaddr[UMASS_INTRIN], 0);
 		err = usbd_open_pipe(sc->sc_iface, sc->sc_epaddr[UMASS_INTRIN],
-				USBD_EXCLUSIVE_USE, &sc->sc_pipe[UMASS_INTRIN]);
+		    USBD_EXCLUSIVE_USE | USBD_MPSAFE, &sc->sc_pipe[UMASS_INTRIN]);
 		if (err) {
 			aprint_error_dev(self, "couldn't open %u-in (intr)\n",
 			    sc->sc_epaddr[UMASS_INTRIN]);
Index: sys/dev/usb/umass_scsipi.c
===================================================================
RCS file: /cvsroot/src/sys/dev/usb/umass_scsipi.c,v
retrieving revision 1.53
diff -u -p -r1.53 umass_scsipi.c
--- sys/dev/usb/umass_scsipi.c	3 Jul 2016 07:27:37 -0000	1.53
+++ sys/dev/usb/umass_scsipi.c	19 Nov 2016 12:27:34 -0000
@@ -194,6 +194,7 @@ umass_scsipi_setup(struct umass_softc *s
 	scbus->sc_adapter.adapt_minphys = umass_scsipi_minphys;
 	scbus->sc_adapter.adapt_ioctl = umass_scsipi_ioctl;
 	scbus->sc_adapter.adapt_getgeom = umass_scsipi_getgeom;
+	scbus->sc_adapter.adapt_flags = SCSIPI_ADAPT_MPSAFE;
 
 	/* Fill in the channel. */
 	memset(&scbus->sc_channel, 0, sizeof(scbus->sc_channel));
@@ -316,9 +317,7 @@ umass_scsipi_request(struct scsipi_chann
 
 		/* Return if command finishes early. */
  done:
-		KERNEL_LOCK(1, curlwp);
 		scsipi_done(xs);
-		KERNEL_UNLOCK_ONE(curlwp);
 		return;
 	default:
 		/* Not supported, nothing to do. */
@@ -397,7 +396,7 @@ umass_scsipi_cb(struct umass_softc *sc, 
 	struct scsipi_xfer *xs = priv;
 	struct scsipi_periph *periph = xs->xs_periph;
 	int cmdlen, senselen;
-	int s;
+	// int s;
 #ifdef UMASS_DEBUG
 	struct timeval tv;
 	u_int delta;
@@ -454,11 +453,7 @@ umass_scsipi_cb(struct umass_softc *sc, 
 	DPRINTFM(UDMASS_CMD, "return xs->error=%d, xs->xs_status=0x%x"
 	    " xs->resid=%d", xs->error, xs->xs_status, xs->resid, 0);
 
-	s = splbio();
-	KERNEL_LOCK(1, curlwp);
 	scsipi_done(xs);
-	KERNEL_UNLOCK_ONE(curlwp);
-	splx(s);
 }
 
 /*
@@ -470,7 +465,6 @@ umass_scsipi_sense_cb(struct umass_softc
 {
 	UMASSHIST_FUNC(); UMASSHIST_CALLED();
 	struct scsipi_xfer *xs = priv;
-	int s;
 
 	DPRINTFM(UDMASS_CMD, "sc %p: xs=%p residue=%d status=%d", sc, xs,
 	    residue, status);
@@ -495,11 +489,7 @@ umass_scsipi_sense_cb(struct umass_softc
 	DPRINTFM(UDMASS_CMD, "return xs->error=%d, xs->xs_status=0x%x"
 	    " xs->resid=%d", xs->error, xs->xs_status, xs->resid, 0);
 
-	s = splbio();
-	KERNEL_LOCK(1, curlwp);
 	scsipi_done(xs);
-	KERNEL_UNLOCK_ONE(curlwp);
-	splx(s);
 }
 
 #if NATAPIBUS > 0
@@ -518,17 +508,13 @@ umass_atapi_probe_device(struct atapibus
 	if (target != UMASS_ATAPI_DRIVE)	/* only probe drive 0 */
 		return;
 
-	KERNEL_LOCK(1, curlwp);
-
 	/* skip if already attached */
 	if (scsipi_lookup_periph(chan, target, 0) != NULL) {
-		KERNEL_UNLOCK_ONE(curlwp);
 		return;
 	}
 
 	periph = scsipi_alloc_periph(M_NOWAIT);
 	if (periph == NULL) {
-		KERNEL_UNLOCK_ONE(curlwp);
 		aprint_error_dev(atapi->sc_dev,
 		    "can't allocate link for drive %d\n", target);
 		return;
@@ -544,7 +530,6 @@ umass_atapi_probe_device(struct atapibus
 	/* Now go ask the device all about itself. */
 	memset(&inqbuf, 0, sizeof(inqbuf));
 	if (scsipi_inquire(periph, &inqbuf, XS_CTL_DISCOVERY) != 0) {
-		KERNEL_UNLOCK_ONE(curlwp);
 		DPRINTFM(UDMASS_SCSI, "scsipi_inquire failed", 0, 0, 0, 0);
 		free(periph, M_DEVBUF);
 		return;
@@ -570,7 +555,5 @@ umass_atapi_probe_device(struct atapibus
 
 	atapi_probe_device(atapi, target, periph, &sa);
 	/* atapi_probe_device() frees the periph when there is no device.*/
-
-	KERNEL_UNLOCK_ONE(curlwp);
 }
 #endif