NetBSD Problem Report #52791

From www@NetBSD.org  Thu Dec  7 21:57:18 2017
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Date: Thu,  7 Dec 2017 21:57:17 +0000 (UTC)
From: webpages@sprow.co.uk
Reply-To: webpages@sprow.co.uk
To: gnats-bugs@NetBSD.org
Subject: Duplicate test in XHCI's TT hub handling
X-Send-Pr-Version: www-1.0

>Number:         52791
>Category:       kern
>Synopsis:       Duplicate test in XHCI's TT hub handling
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          closed
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Dec 07 22:00:00 +0000 2017
>Closed-Date:    Thu Dec 21 22:42:03 +0000 2017
>Last-Modified:  Thu Dec 21 22:42:03 +0000 2017
>Originator:     Robert Sprowson
>Release:        
>Organization:
>Environment:
>Description:
When checking the conditions for turning on TT hub support, a check is made whether dev->ud_myhub is NULL before proceeding to picking the pointer for the ud_depth member.
In the same expression it's checked again before picking the ud_speed member.
There's no need to check it twice, C will evaluate the expression in the order it's written.

See patch against src/sys/dev/usb/xhci.c (same construct twice).
>How-To-Repeat:

>Fix:
--- xhci.1.77.c	2017-11-17 08:22:02.0 +0000
+++ xhci.c	2017-12-07 21:49:29.0 +0000
@@ -3179,8 +3179,7 @@
 	 */
 	if (dev->ud_myhsport != NULL &&
 	    dev->ud_myhub != NULL && dev->ud_myhub->ud_depth != 0 &&
-	    (dev->ud_myhub != NULL &&
-	     dev->ud_myhub->ud_speed == USB_SPEED_HIGH) &&
+	    dev->ud_myhub->ud_speed == USB_SPEED_HIGH &&
 	    (speed == USB_SPEED_LOW || speed == USB_SPEED_FULL)) {
 		ttportnum = dev->ud_myhsport->up_portno;
 		tthubslot = dev->ud_myhsport->up_parent->ud_addr;
@@ -3221,8 +3220,7 @@
 	else if (!ishub &&
 	     (speed == USB_SPEED_LOW || speed == USB_SPEED_FULL) &&
 	     dev->ud_myhub != NULL && dev->ud_myhub->ud_depth != 0 &&
-	     (dev->ud_myhub != NULL &&
-	      dev->ud_myhub->ud_speed == USB_SPEED_HIGH) &&
+	     dev->ud_myhub->ud_speed == USB_SPEED_HIGH &&
 	     dev->ud_myhsport != NULL &&
 	     IS_TTHUB(&dev->ud_myhsport->up_parent->ud_ddesc))
 		usemtt = true;

>Release-Note:

>Audit-Trail:
From: "Christos Zoulas" <christos@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/52791 CVS commit: src/sys/dev/usb
Date: Thu, 7 Dec 2017 17:56:23 -0500

 Module Name:	src
 Committed By:	christos
 Date:		Thu Dec  7 22:56:23 UTC 2017

 Modified Files:
 	src/sys/dev/usb: xhci.c

 Log Message:
 PR/52791: Robert Sprowson: avoid duplicate tests (use accessor variables)


 To generate a diff of this commit:
 cvs rdiff -u -r1.77 -r1.78 src/sys/dev/usb/xhci.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

From: "Soren Jacobsen" <snj@netbsd.org>
To: gnats-bugs@gnats.NetBSD.org
Cc: 
Subject: PR/52791 CVS commit: [netbsd-8] src/sys/dev/usb
Date: Thu, 21 Dec 2017 21:53:32 +0000

 Module Name:	src
 Committed By:	snj
 Date:		Thu Dec 21 21:53:32 UTC 2017

 Modified Files:
 	src/sys/dev/usb [netbsd-8]: xhci.c

 Log Message:
 Pull up following revision(s) (requested by skrll in ticket #459):
 	sys/dev/usb/xhci.c: 1.78, 1.83
 PR/52791: Robert Sprowson: avoid duplicate tests (use accessor variables)
 --
 Fix the logic around TT Hub Slot ID, TT Port Number and Multi-TT in
 xhci_setup_tthub.  TT Hub/Port need to reference the upstream HS hub and
 Multi-TT needs to reflect the capabilities of a HS hub itself or the same
 upstream HS hub.


 To generate a diff of this commit:
 cvs rdiff -u -r1.72.2.4 -r1.72.2.5 src/sys/dev/usb/xhci.c

 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.

State-Changed-From-To: open->closed
State-Changed-By: snj@NetBSD.org
State-Changed-When: Thu, 21 Dec 2017 22:42:03 +0000
State-Changed-Why:
christos handled it. thanks!


>Unformatted:

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