svn commit: r228760 - head/sys/dev/usb

[Andriy Gapon]

Author: avg
Date: Wed Dec 21 10:52:17 2011
New Revision: 228760
URL: http://svn.freebsd.org/changeset/base/228760

Log:
  adapt usb transfer code for SCHEDULER_STOPPED
  
  When SCHEDULER_STOPPED() is true the mtx_owned() call may return
  an unexpected and thus meaningless result.
  So, in the code paths that can be reached when SCHEDULER_STOPPED() is true
  we need to protect the mtx_owned() calls with the SCHEDULER_STOPPED()
  checks and ensure that an appropriate branch is taken in each case.
  
  Reviewed by:	hselasky
  MFC after:	3 months
  X-MFC after:	r228424

Modified:
  head/sys/dev/usb/usb_transfer.c

Modified: head/sys/dev/usb/usb_transfer.c
==============================================================================
--- head/sys/dev/usb/usb_transfer.c	Wed Dec 21 09:08:41 2011	(r228759)
+++ head/sys/dev/usb/usb_transfer.c	Wed Dec 21 10:52:17 2011	(r228760)
@@ -2150,7 +2150,7 @@ usbd_callback_wrapper(struct usb_xfer_qu
 	struct usb_xfer_root *info = xfer->xroot;
 
 	USB_BUS_LOCK_ASSERT(info->bus, MA_OWNED);
-	if (!mtx_owned(info->xfer_mtx)) {
+	if (!mtx_owned(info->xfer_mtx) && !SCHEDULER_STOPPED()) {
 		/*
 	       	 * Cases that end up here:
 		 *
@@ -3119,14 +3119,14 @@ usbd_transfer_poll(struct usb_xfer **ppx
 
 		/* make sure that the BUS mutex is not locked */
 		drop_bus = 0;
-		while (mtx_owned(&xroot->udev->bus->bus_mtx)) {
+		while (mtx_owned(&xroot->udev->bus->bus_mtx) && !SCHEDULER_STOPPED()) {
 			mtx_unlock(&xroot->udev->bus->bus_mtx);
 			drop_bus++;
 		}
 
 		/* make sure that the transfer mutex is not locked */
 		drop_xfer = 0;
-		while (mtx_owned(xroot->xfer_mtx)) {
+		while (mtx_owned(xroot->xfer_mtx) && !SCHEDULER_STOPPED()) {
 			mtx_unlock(xroot->xfer_mtx);
 			drop_xfer++;
 		}