From patchwork Tue Apr 23 19:44:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andre Guedes X-Patchwork-Id: 1089755 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=intel.com Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44pbHQ2bD9z9sML for ; Wed, 24 Apr 2019 06:52:34 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727357AbfDWUwc (ORCPT ); Tue, 23 Apr 2019 16:52:32 -0400 Received: from mga17.intel.com ([192.55.52.151]:34500 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726157AbfDWUwc (ORCPT ); Tue, 23 Apr 2019 16:52:32 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Apr 2019 13:52:31 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,387,1549958400"; d="scan'208";a="136767214" Received: from otc-tsn-1.jf.intel.com ([10.54.70.5]) by orsmga008.jf.intel.com with ESMTP; 23 Apr 2019 13:47:30 -0700 From: Andre Guedes To: netdev@vger.kernel.org Cc: vinicius.gomes@intel.com, xiyou.wangcong@gmail.com Subject: [PATCH net-next v2 2/5] net: sched: taprio: Refactor taprio_get_start_time() Date: Tue, 23 Apr 2019 12:44:21 -0700 Message-Id: <20190423194424.3155-3-andre.guedes@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190423194424.3155-1-andre.guedes@intel.com> References: <20190423194424.3155-1-andre.guedes@intel.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch does a code refactoring to taprio_get_start_time() function to improve readability and report error properly. If 'base' time is later than 'now', the start time is equal to 'base' and taprio_get_start_time() is done. That's the natural case so we move that code to the beginning of the function. Also, if 'cycle' calculation is zero, something went really wrong with taprio and we should log that internal error properly. Signed-off-by: Andre Guedes --- net/sched/sch_taprio.c | 37 +++++++++++++++++++++++-------------- 1 file changed, 23 insertions(+), 14 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index d91a7ec67348..d0aae7b5e608 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -539,7 +539,7 @@ static int taprio_parse_mqprio_opt(struct net_device *dev, return 0; } -static ktime_t taprio_get_start_time(struct Qdisc *sch) +static int taprio_get_start_time(struct Qdisc *sch, ktime_t *start) { struct taprio_sched *q = qdisc_priv(sch); struct sched_entry *entry; @@ -547,27 +547,33 @@ static ktime_t taprio_get_start_time(struct Qdisc *sch) s64 n; base = ns_to_ktime(q->base_time); - cycle = 0; + now = q->get_time(); + + if (ktime_after(base, now)) { + *start = base; + return 0; + } /* Calculate the cycle_time, by summing all the intervals. */ + cycle = 0; list_for_each_entry(entry, &q->entries, list) cycle = ktime_add_ns(cycle, entry->interval); - if (!cycle) - return base; - - now = q->get_time(); - - if (ktime_after(base, now)) - return base; + /* The qdisc is expected to have at least one sched_entry. Moreover, + * any entry must have 'interval' > 0. Thus if the cycle time is zero, + * something went really wrong. In that case, we should warn about this + * inconsistent state and return error. + */ + if (WARN_ON(!cycle)) + return -EFAULT; /* Schedule the start time for the beginning of the next * cycle. */ n = div64_s64(ktime_sub_ns(now, base), cycle); - - return ktime_add_ns(base, (n + 1) * cycle); + *start = ktime_add_ns(base, (n + 1) * cycle); + return 0; } static void taprio_start_sched(struct Qdisc *sch, ktime_t start) @@ -716,9 +722,12 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, } taprio_set_picos_per_byte(dev, q); - start = taprio_get_start_time(sch); - if (!start) - return 0; + + err = taprio_get_start_time(sch, &start); + if (err < 0) { + NL_SET_ERR_MSG(extack, "Internal error: failed get start time"); + return err; + } taprio_start_sched(sch, start);