From 5a280dbdd62cfe0f912cb9c81255a7f46f82a981 Mon Sep 17 00:00:00 2001
From: Hans Petter Selasky <hselasky@FreeBSD.org>
Date: Fri, 30 Aug 2013 10:39:56 +0000
Subject: [PATCH] Simplify pause_sbt() logic. Don't call DELAY() if remainder
 is less than or equal to zero.

---
 sys/kern/kern_synch.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c
index 0996f4e8a82..b0e19082c91 100644
--- a/sys/kern/kern_synch.c
+++ b/sys/kern/kern_synch.c
@@ -356,10 +356,7 @@ msleep_spin_sbt(void *ident, struct mtx *mtx, const char *wmesg,
 int
 pause_sbt(const char *wmesg, sbintime_t sbt, sbintime_t pr, int flags)
 {
-	int sbt_sec;
-
-	sbt_sec = sbintime_getsec(sbt);
-	KASSERT(sbt_sec >= 0, ("pause: timo must be >= 0"));
+	KASSERT(sbt >= 0, ("pause: timeout must be >= 0"));
 
 	/* silently convert invalid timeouts */
 	if (sbt == 0)
@@ -370,11 +367,14 @@ pause_sbt(const char *wmesg, sbintime_t sbt, sbintime_t pr, int flags)
 		 * We delay one second at a time to avoid overflowing the
 		 * system specific DELAY() function(s):
 		 */
-		while (sbt_sec > 0) {
+		while (sbt >= SBT_1S) {
 			DELAY(1000000);
-			sbt_sec--;
+			sbt -= SBT_1S;
 		}
-		DELAY((sbt & 0xffffffff) / SBT_1US);
+		/* Do the delay remainder, if any */
+		sbt = (sbt + SBT_1US - 1) / SBT_1US;
+		if (sbt > 0)
+			DELAY(sbt);
 		return (0);
 	}
 	return (_sleep(&pause_wchan[curcpu], NULL, 0, wmesg, sbt, pr, flags));