From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: [PATCH net-next v2 2/2] netem: remove unnecessary 64 bit modulus Date: Tue, 14 Nov 2017 11:27:02 -0800 Message-ID: <20171114192702.31193-3-sthemmin@microsoft.com> References: <20171114192702.31193-1-sthemmin@microsoft.com> Cc: netdev@vger.kernel.org, Stephen Hemminger To: stephen@networkplumber.org, jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net Return-path: Received: from mail-pg0-f67.google.com ([74.125.83.67]:57115 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752510AbdKNT1M (ORCPT ); Tue, 14 Nov 2017 14:27:12 -0500 Received: by mail-pg0-f67.google.com with SMTP id z184so10710761pgd.13 for ; Tue, 14 Nov 2017 11:27:12 -0800 (PST) In-Reply-To: <20171114192702.31193-1-sthemmin@microsoft.com> Sender: netdev-owner@vger.kernel.org List-ID: Fix compilation on 32 bit platforms (where doing modulus operation with 64 bit requires extra glibc functions) by truncation. The jitter for table distribution is limited to a 32 bit value because random numbers are scaled as 32 bit value. Also fix some whitespace. Fixes: 99803171ef04 ("netem: add uapi to express delay and jitter in nanoseconds") Reported-by: Randy Dunlap Signed-off-by: Stephen Hemminger --- net/sched/sch_netem.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index 644323d6081c..dd70924cbcdf 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -312,9 +312,9 @@ static bool loss_event(struct netem_sched_data *q) * std deviation sigma. Uses table lookup to approximate the desired * distribution, and a uniformly-distributed pseudo-random source. */ -static s64 tabledist(s64 mu, s64 sigma, +static s64 tabledist(s64 mu, s32 sigma, struct crndstate *state, - const struct disttable *dist) + const struct disttable *dist) { s64 x; long t; @@ -327,7 +327,7 @@ static s64 tabledist(s64 mu, s64 sigma, /* default uniform distribution */ if (dist == NULL) - return (rnd % (2*sigma)) - sigma + mu; + return (rnd % (2 * sigma)) - sigma + mu; t = dist->table[rnd % dist->size]; x = (sigma % NETEM_DIST_SCALE) * t; -- 2.11.0