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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 E92B5C43603 for ; Mon, 9 Dec 2019 16:43:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C350A2073D for ; Mon, 9 Dec 2019 16:43:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726691AbfLIQnm (ORCPT ); Mon, 9 Dec 2019 11:43:42 -0500 Received: from mga05.intel.com ([192.55.52.43]:15470 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726484AbfLIQnl (ORCPT ); Mon, 9 Dec 2019 11:43:41 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Dec 2019 08:43:41 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,296,1571727600"; d="scan'208";a="414130348" Received: from smile.fi.intel.com (HELO smile) ([10.237.68.40]) by fmsmga006.fm.intel.com with ESMTP; 09 Dec 2019 08:43:39 -0800 Received: from andy by smile with local (Exim 4.93-RC5) (envelope-from ) id 1ieM8I-00017c-Mq; Mon, 09 Dec 2019 18:43:38 +0200 Date: Mon, 9 Dec 2019 18:43:38 +0200 From: Andy Shevchenko To: Mark Fasheh , Joel Becker , Joseph Qi , ocfs2-devel@oss.oracle.com, Ariel Elior , Sudarsana Kalluru , GR-everest-linux-l2@marvell.com, "David S. Miller" , netdev@vger.kernel.org, Colin Ian King Subject: Re: [PATCH v2] ocfs2/dlm: Move BITS_TO_BYTES() to bitops.h for wider use Message-ID: <20191209164338.GO32742@smile.fi.intel.com> References: <20190827163717.44101-1-andriy.shevchenko@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190827163717.44101-1-andriy.shevchenko@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Aug 27, 2019 at 07:37:17PM +0300, Andy Shevchenko wrote: > There are users already and will be more of BITS_TO_BYTES() macro. > Move it to bitops.h for wider use. > > In the case of ocfs2 the replacement is identical. > > As for bnx2x, there are two places where floor version is used. > In the first case to calculate the amount of structures that can fit > one memory page. In this case obviously the ceiling variant is correct and > original code might have a potential bug, if amount of bits % 8 is not 0. > In the second case the macro is used to calculate bytes transmitted in one > microsecond. This will work for all speeds which is multiply of 1Gbps without > any change, for the rest new code will give ceiling value, for instance 100Mbps > will give 13 bytes, while old code gives 12 bytes and the arithmetically > correct one is 12.5 bytes. Further the value is used to setup timer threshold > which in any case has its own margins due to certain resolution. I don't see > here an issue with slightly shifting thresholds for low speed connections, the > card is supposed to utilize highest available rate, which is usually 10Gbps. Anybody to comment on bnx2 change? Can we survive with this applied? > > Reviewed-by: Joseph Qi > Signed-off-by: Andy Shevchenko > --- > - described bnx2x cases in the commit message > - appended Rb (for ocfs2) > > drivers/net/ethernet/broadcom/bnx2x/bnx2x_init.h | 1 - > fs/ocfs2/dlm/dlmcommon.h | 4 ---- > include/linux/bitops.h | 1 + > 3 files changed, 1 insertion(+), 5 deletions(-) > > diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_init.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_init.h > index 066765fbef06..0a59a09ef82f 100644 > --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_init.h > +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_init.h > @@ -296,7 +296,6 @@ static inline void bnx2x_dcb_config_qm(struct bnx2x *bp, enum cos_mode mode, > * possible, the driver should only write the valid vnics into the internal > * ram according to the appropriate port mode. > */ > -#define BITS_TO_BYTES(x) ((x)/8) > > /* CMNG constants, as derived from system spec calculations */ > > diff --git a/fs/ocfs2/dlm/dlmcommon.h b/fs/ocfs2/dlm/dlmcommon.h > index aaf24548b02a..0463dce65bb2 100644 > --- a/fs/ocfs2/dlm/dlmcommon.h > +++ b/fs/ocfs2/dlm/dlmcommon.h > @@ -688,10 +688,6 @@ struct dlm_begin_reco > __be32 pad2; > }; > > - > -#define BITS_PER_BYTE 8 > -#define BITS_TO_BYTES(bits) (((bits)+BITS_PER_BYTE-1)/BITS_PER_BYTE) > - > struct dlm_query_join_request > { > u8 node_idx; > diff --git a/include/linux/bitops.h b/include/linux/bitops.h > index cf074bce3eb3..79d80f5ddf7b 100644 > --- a/include/linux/bitops.h > +++ b/include/linux/bitops.h > @@ -5,6 +5,7 @@ > #include > > #define BITS_PER_TYPE(type) (sizeof(type) * BITS_PER_BYTE) > +#define BITS_TO_BYTES(nr) DIV_ROUND_UP(nr, BITS_PER_BYTE) > #define BITS_TO_LONGS(nr) DIV_ROUND_UP(nr, BITS_PER_TYPE(long)) > > extern unsigned int __sw_hweight8(unsigned int w); > -- > 2.23.0.rc1 > -- With Best Regards, Andy Shevchenko