From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 33C182459F1 for ; Mon, 7 Apr 2025 12:28:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744028921; cv=none; b=k4QjDoxOiUfdPEgQST8VhamG70sCVxWfL+/qkClqkXPldd+cgXNacmqUdJYaXYI5xMvEvwouFM0hopJDeEDZIBQYWVePtArLDkadqmfMZQD0iEsg9wIb1Oj4qA5PBi6TH01aW3xYznXewfOrboxsQarXSvTwlX8D6qiTQyvHw8A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744028921; c=relaxed/simple; bh=dDCLsoBqPfjWbCG4p1BxBYTwjiD+HPi7id2DzJFDYuY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XkRoALacc34d2ZZSuZfeEFNQtz+pvHGV6NcKaB2vzAbmUIVDvaC8tRxDIahBreeMGlRibRI1eL1fiBW3FR3Q9K848j43fCoJaV+CVCtA1q5rKWxHE4DVi9mX8CpWhnWM27NvOyREfK4YkmUircND1fOazLnwY1ATlijwz2D8cP8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=kernel.org; spf=fail smtp.mailfrom=kernel.org; arc=none smtp.client-ip=198.175.65.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=kernel.org Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=kernel.org X-CSE-ConnectionGUID: D5T64hA0TRON5uuxvF4OSw== X-CSE-MsgGUID: RigfFxLOTQWRd2lXgQPYuw== X-IronPort-AV: E=McAfee;i="6700,10204,11397"; a="45503784" X-IronPort-AV: E=Sophos;i="6.15,194,1739865600"; d="scan'208";a="45503784" Received: from orviesa006.jf.intel.com ([10.64.159.146]) by orvoesa108.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Apr 2025 05:28:39 -0700 X-CSE-ConnectionGUID: V7WAbuhdRRaCz1Fu5rD9lg== X-CSE-MsgGUID: cnCsxASrQrSUBASJDuV33w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,194,1739865600"; d="scan'208";a="127924698" Received: from smile.fi.intel.com ([10.237.72.58]) by orviesa006.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Apr 2025 05:28:38 -0700 Received: from andy by smile.fi.intel.com with local (Exim 4.98.2) (envelope-from ) id 1u1lac-0000000A44A-2D5l; Mon, 07 Apr 2025 15:28:34 +0300 Date: Mon, 7 Apr 2025 15:28:34 +0300 From: Andy Shevchenko To: David Laight Cc: Greg KH , Abraham Samuel Adekunle , julia.lawall@inria.fr, outreachy@lists.linux.dev, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, dan.carpenter@linaro.org Subject: Re: [PATCH v4] staging: rtl8723bs: Use % 4096u instead of & 0xfff Message-ID: References: <2025040757-clergyman-finalist-0c63@gregkh> <2025040752-unrefined-labored-8c8c@gregkh> <20250407132115.11ded3d9@pumpkin> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250407132115.11ded3d9@pumpkin> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Mon, Apr 07, 2025 at 01:21:15PM +0100, David Laight wrote: > On Mon, 7 Apr 2025 08:53:30 +0200 > Greg KH wrote: > > On Mon, Apr 07, 2025 at 08:36:35AM +0200, Greg KH wrote: > > > On Mon, Apr 07, 2025 at 06:30:50AM +0000, Abraham Samuel Adekunle wrote: > > > > - psta->sta_xmitpriv.txseq_tid[pattrib->priority] &= 0xFFF; > > > > + psta->sta_xmitpriv.txseq_tid[pattrib->priority] &= 4096u; > > > > > > I do not see a modulo operation here, only another & operation. > > > > > > > pattrib->seqnum = psta->sta_xmitpriv.txseq_tid[pattrib->priority]; > > > > > > > > SetSeqNum(hdr, pattrib->seqnum); > > > > @@ -963,11 +963,11 @@ s32 rtw_make_wlanhdr(struct adapter *padapter, u8 *hdr, struct pkt_attrib *pattr > > > > if (SN_LESS(pattrib->seqnum, tx_seq)) { > > > > pattrib->ampdu_en = false;/* AGG BK */ > > > > } else if (SN_EQUAL(pattrib->seqnum, tx_seq)) { > > > > - psta->BA_starting_seqctrl[pattrib->priority & 0x0f] = (tx_seq+1)&0xfff; > > > > + psta->BA_starting_seqctrl[pattrib->priority & 0x0f] = (tx_seq+1)&4096u; > > > > > > This also looks odd, nothing is being "AND" here, it's an address value > > > being set (and an odd one at that, but that's another issue...) > > > > Sorry, no, I was wrong, it is being & here, but not %. My fault, > > the lack of spaces here threw me. > > It is still wrong '& 0xfff' => '% 4096u'. Why? > But it is all rather pointless especially if you can't test it. > Plausibly more useful would be to find ALL of the uses of 0xfff/4096 (I suspect > there is an array lurking somewhere) and change them to use the same constant. > But you need to be able to test the changes - or at least discover that > they make absolutely no difference to the generated object code. The problem with &, it's not non-power-of-2 tolerable solution. Also using hexadecimal there is not so helpful as when we are talking about sequences (or indices in the circular buffer), the decimal makes more sense. -- With Best Regards, Andy Shevchenko