* add a process reference counting variable to struct usbd_device

* add functions to increment and decrement the reference count, and a
  function to wait until the reference count is zero
ok martynas@

3 files changed, 29 insertions, 4 deletions

diff --git a/sys/dev/usb/usbdi.c b/sys/dev/usb/usbdi.c
index 01e88d93a03..78e80e7c882 100644
--- a/sys/dev/usb/usbdi.c
+++ b/sys/dev/usb/usbdi.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: usbdi.c,v 1.41 2010/12/06 04:25:27 jakemsr Exp $ */
+/*	$OpenBSD: usbdi.c,v 1.42 2010/12/30 05:10:35 jakemsr Exp $ */
 /*	$NetBSD: usbdi.c,v 1.103 2002/09/27 15:37:38 provos Exp $	*/
 /*	$FreeBSD: src/sys/dev/usb/usbdi.c,v 1.28 1999/11/17 22:33:49 n_hibma Exp $	*/
 
@@ -97,6 +97,26 @@ usbd_deactivate(usbd_device_handle dev)
 	dev->dying = 1;
 }
 
+void
+usbd_ref_incr(usbd_device_handle dev)
+{
+	dev->ref_cnt++;
+}
+
+void
+usbd_ref_decr(usbd_device_handle dev)
+{
+	if (--dev->ref_cnt == 0 && dev->dying)
+		wakeup(&dev->ref_cnt);
+}
+
+void
+usbd_ref_wait(usbd_device_handle dev)
+{
+	while (dev->ref_cnt > 0)
+		tsleep(&dev->ref_cnt, PWAIT, "usbref", hz * 60);
+}
+
 static __inline int
 usbd_xfer_isread(usbd_xfer_handle xfer)
 {
diff --git a/sys/dev/usb/usbdi.h b/sys/dev/usb/usbdi.h
index 5996ad61c65..c7bc9a4c09e 100644
--- a/sys/dev/usb/usbdi.h
+++ b/sys/dev/usb/usbdi.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: usbdi.h,v 1.36 2010/12/06 04:25:27 jakemsr Exp $ */
+/*	$OpenBSD: usbdi.h,v 1.37 2010/12/30 05:10:35 jakemsr Exp $ */
 /*	$NetBSD: usbdi.h,v 1.62 2002/07/11 21:14:35 augustss Exp $	*/
 /*	$FreeBSD: src/sys/dev/usb/usbdi.h,v 1.18 1999/11/17 22:33:49 n_hibma Exp $	*/
 
@@ -168,6 +168,10 @@ int usbd_ratecheck(struct timeval *last);
 int usbd_is_dying(usbd_device_handle);
 void usbd_deactivate(usbd_device_handle);
 
+void usbd_ref_incr(usbd_device_handle);
+void usbd_ref_decr(usbd_device_handle);
+void usbd_ref_wait(usbd_device_handle);
+
 /* An iterator for descriptors. */
 typedef struct {
 	const uByte *cur;
diff --git a/sys/dev/usb/usbdivar.h b/sys/dev/usb/usbdivar.h
index 2ebdb9b9d9b..f53369945ad 100644
--- a/sys/dev/usb/usbdivar.h
+++ b/sys/dev/usb/usbdivar.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: usbdivar.h,v 1.40 2010/12/06 04:25:27 jakemsr Exp $ */
+/*	$OpenBSD: usbdivar.h,v 1.41 2010/12/30 05:10:35 jakemsr Exp $ */
 /*	$NetBSD: usbdivar.h,v 1.70 2002/07/11 21:14:36 augustss Exp $	*/
 /*	$FreeBSD: src/sys/dev/usb/usbdivar.h,v 1.11 1999/11/17 22:33:51 n_hibma Exp $	*/
 
@@ -125,7 +125,8 @@ struct usbd_bus {
 struct usbd_device {
 	struct usbd_bus	       *bus;           /* our controller */
 	struct usbd_pipe       *default_pipe;  /* pipe 0 */
-	u_int8_t		dying;	       /* removed */
+	u_int8_t		dying;	       /* hardware removed */
+	u_int8_t		ref_cnt;       /* # of procs using device */
 	u_int8_t		address;       /* device address */
 	u_int8_t		config;	       /* current configuration # */
 	u_int8_t		depth;         /* distance from root hub */