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=-0.8 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 ECF3FC43143 for ; Thu, 13 Sep 2018 19:45:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A7BD920853 for ; Thu, 13 Sep 2018 19:45:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sfE5DRX+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A7BD920853 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com 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 S1728147AbeINA4F (ORCPT ); Thu, 13 Sep 2018 20:56:05 -0400 Received: from mail-it0-f52.google.com ([209.85.214.52]:35759 "EHLO mail-it0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726839AbeINA4E (ORCPT ); Thu, 13 Sep 2018 20:56:04 -0400 Received: by mail-it0-f52.google.com with SMTP id 139-v6so9344657itf.0; Thu, 13 Sep 2018 12:45:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RhGKjVNuZ69pvS4r+DB/mHzU5FoCyggNhMHf7+Jacgo=; b=sfE5DRX+sEtgkCCDEEKsY4BozdyC6YIRcV3C93KKkqSU6bgjOIML157NAgv9u8Sz+M HjhpNgWeDfnKc9scCekj6kM9+xJsH8OYpFeZftA/K3+YU3aKVFiJ6VdIfDBzQfSNBZV3 xEUGrUHzH50OwHBqdz/nBDGBgfbXSbSRAY09+Sik6bx615hQsj1R7J2ksDxBK5nfKpsd h/SG2EG/LHyPVe4fglFFUOOOycH9o7gEbKvTCeRYXcqImHVevVXBpPsGr5DFLRBtdwMt 61JUHXZeo+zoSKrUf/eLXjNHTnAbF/v5m5wvjOca+oGXv0Zr65/WVRIgUIJSVTGk+ZmV vtTw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=RhGKjVNuZ69pvS4r+DB/mHzU5FoCyggNhMHf7+Jacgo=; b=my35JHkEREHZB6wynAH1W0RogG7QrW2uEy3EBfxZXeqZTyKSjLkh1zzS1wG10adXhZ FcqJzWKvS1rYrR9s0vAIFKlBjKB6PSYnWTDsw5xYnCf+xIm2Xn8ZTfQHP7sDAVJWjs7D 6qCW4WuyS7D5p++Z2tpma9F+dSFtazb8DwLHyAqp5KUldRJzAAxbgNvCx50WERmumsdW STOJBQIRI4rYgHXWNVcoJfOP+3JqOwFoP62JwzNigraEv8SYXgIdZ6MYwMb/IL9lKK1n Mgk0O8S47Md1RNHYp7rzoZWjBalZcuIp/+slgSJRSziRPS0ZshjfICAZjDdpsNd53CYS hBqg== X-Gm-Message-State: APzg51AvituTdLVkV7WH9O/l8EFhid+E5aWgEzF9nZMUEKgCgIhzK4Em lsLS+EZiFT3caAOHl9lcLA2B9DupwRTUW8djORmiun6/ X-Google-Smtp-Source: ANB0VdZlNg4l7YEfrN4EfHoDCdVOORpZ6+3cq3xIU+0iX0OgAV7sGWaz2D5OlV9d5/OTlWhLNvEA0HTqXuOrs7+z6E8= X-Received: by 2002:a24:68c2:: with SMTP id v185-v6mr7626473itb.128.1536867907420; Thu, 13 Sep 2018 12:45:07 -0700 (PDT) MIME-Version: 1.0 References: <20180912183519.GA31506@vnote> <20180912185517.GE3902@linux-r8p5> In-Reply-To: From: Eugene Korenevsky Date: Thu, 13 Sep 2018 22:44:56 +0300 Message-ID: Subject: Re: [PATCH v3] efi: take size of partition entry from GPT header To: David.Laight@aculab.com Cc: Davidlohr Bueso , linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, Ard Biesheuvel Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Please rearrange this like: > > > > for (i = 0; i < le32_to_cpu(gpt->num_partition_entries) && > > i < state->limit-1; i++) > > Better still cache le32_to_cpu(gpt->num_partition_entries) to a local > so that it only has to be calculated once (even if it gets spilled > to the stack). > It can be bounded by state->limit-1 at the same time. This is block I/O, slow path. No need for such micro optimizations here. GCC is capable to do such optimizations automatically, and it does as I can see from disassembly. Anyway this would be a subject for another patch. -- Eugene