From: Simon Wilkinson <sxw@your-file-system.com>
Date: Sat, 18 Jun 2011 10:48:45 +0000 (+0100)
Subject: rx: Make clock_Add correctly add to itself
X-Git-Tag: upstream/1.8.0_pre1^2~3618
X-Git-Url: https://git.michaelhowe.org/gitweb/?a=commitdiff_plain;h=784babbea1247660f39463403233589a74c6e73b;p=packages%2Fo%2Fopenafs.git

rx: Make clock_Add correctly add to itself

With the existing clock_Add code, the following:
    struct clock a = {2, 800000};
    clock_Add(&a, &a);
gives a clock value of {6, 600000}, rather than the expected {5, 60000}.

This is because the ordering of instructions leads it to double count
the carry on the seconds field. Reorder the instructions so that the
carry is correctly applied.

Change-Id: Ia71b387ce521a11e4caf9ec200907efe1d2be8ff
Reviewed-on: http://gerrit.openafs.org/4864
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>
---

diff --git a/src/rx/rx_clock.h b/src/rx/rx_clock.h
index 483bb07aa..2bdc0b81e 100644
--- a/src/rx/rx_clock.h
+++ b/src/rx/rx_clock.h
@@ -128,11 +128,11 @@ extern int clock_nUpdates;
 /* Add time c2 to time c1.  Both c2 and c1 must be positive times. */
 #define	clock_Add(c1, c2)					\
     BEGIN							\
+	(c1)->sec += (c2)->sec;					\
 	if (((c1)->usec += (c2)->usec) >= 1000000) {		\
 	    (c1)->usec -= 1000000;				\
 	    (c1)->sec++;					\
 	}							\
-	(c1)->sec += (c2)->sec;					\
     END
 
 #define USEC(cp)        (((cp)->sec * 1000000) + (cp)->usec)