From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9A5D2C004D2 for ; Tue, 2 Oct 2018 13:30:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 623A021480 for ; Tue, 2 Oct 2018 13:30:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 623A021480 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730630AbeJBUOI (ORCPT ); Tue, 2 Oct 2018 16:14:08 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33728 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729722AbeJBUOI (ORCPT ); Tue, 2 Oct 2018 16:14:08 -0400 Received: from localhost (24-104-73-23-ip-static.hfc.comcastbusiness.net [24.104.73.23]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 6CEFABF0; Tue, 2 Oct 2018 13:30:45 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jacob Keller , Anirudh Venkataramanan , Tony Brelinski , Jeff Kirsher , Sasha Levin Subject: [PATCH 4.18 199/228] ice: Use order_base_2 to calculate higher power of 2 Date: Tue, 2 Oct 2018 06:24:56 -0700 Message-Id: <20181002132511.373049505@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20181002132459.032960735@linuxfoundation.org> References: <20181002132459.032960735@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jacob Keller [ Upstream commit 1eb43fc754485d772b1165118a8fb80c385f0492 ] Currently, we use a combination of ilog2 and is_power_of_2() to calculate the next power of 2 for the qcount. This appears to be causing a warning on some combinations of GCC and the Linux kernel: MODPOST 1 modules WARNING: "____ilog2_NaN" [ice.ko] undefined! This appears to because because GCC realizes that qcount could be zero in some circumstances and thus attempts to link against the intentionally undefined ___ilog2_NaN function. The order_base_2 function is intentionally defined to return 0 when passed 0 as an argument, and thus will be safe to use here. This not only fixes the warning but makes the resulting code slightly cleaner, and is really what we should have used originally. Also update the comment to make it more clear that we are rounding up, not just incrementing the ilog2 of qcount unconditionally. Signed-off-by: Jacob Keller Signed-off-by: Anirudh Venkataramanan Tested-by: Tony Brelinski Signed-off-by: Jeff Kirsher Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/net/ethernet/intel/ice/ice_main.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) --- a/drivers/net/ethernet/intel/ice/ice_main.c +++ b/drivers/net/ethernet/intel/ice/ice_main.c @@ -1313,11 +1313,8 @@ static void ice_vsi_setup_q_map(struct i qcount = numq_tc; } - /* find higher power-of-2 of qcount */ - pow = ilog2(qcount); - - if (!is_power_of_2(qcount)) - pow++; + /* find the (rounded up) power-of-2 of qcount */ + pow = order_base_2(qcount); for (i = 0; i < ICE_MAX_TRAFFIC_CLASS; i++) { if (!(vsi->tc_cfg.ena_tc & BIT(i))) {