PERFORCE change 156139 for review

[Weongyo Jeong]

http://perforce.freebsd.org/chv.cgi?CH=156139

Change 156139 by weongyo at weongyo_ws on 2009/01/14 07:05:52

	fix a ehci's bug that it's occurred when the xfers are aborted under
	heavy loads or working.  It looks this bug exists since r158869 so
	needs to revert a part of the previous.
	
	This helps some panics related with aborting the xfers of ehci(4).
	
	Reviewed by:	imp
	Tested by:	sam

Affected files ...

.. //depot/projects/vap/sys/dev/usb/ehci.c#18 edit

Differences ...

==== //depot/projects/vap/sys/dev/usb/ehci.c#18 (text+ko) ====

@@ -2753,7 +2753,7 @@
 
 	/* We will change them to point here */
 	snext = exfer->sqtdend->nextqtd;
-	next = htohc32(sc, snext->physaddr);
+	next = (snext != NULL) ? htohc32(sc, snext->physaddr) : EHCI_NULL(sc);
 
 	/*
 	 * Now loop through any qTDs before us and keep track of the pointer