From patchwork Wed Oct 21 09:15:23 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: brookxu X-Patchwork-Id: 1385456 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-ext4-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20161025 header.b=YNFFfBwj; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CGPxW3GX1z9sTR for ; Wed, 21 Oct 2020 20:16:15 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437557AbgJUJQP (ORCPT ); Wed, 21 Oct 2020 05:16:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2437538AbgJUJQO (ORCPT ); Wed, 21 Oct 2020 05:16:14 -0400 Received: from mail-pf1-x442.google.com (mail-pf1-x442.google.com [IPv6:2607:f8b0:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CC956C0613CE for ; Wed, 21 Oct 2020 02:16:14 -0700 (PDT) Received: by mail-pf1-x442.google.com with SMTP id f19so1103236pfj.11 for ; Wed, 21 Oct 2020 02:16:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=A9db66j5jgBwQHfPYVkQHfIXD2LLsb4yznWteentD3Y=; b=YNFFfBwjI90ifdG/sAEfyOZ1tUaGOOYvf4nr80E3oNMJj1+gCbOKv8/KglcfasyTOG S6oP2iy5mUI23N9tZ+9L4tDQy2WnGlesXt9O7LXA6uSuewXXl6KWGhbwY4ZBR0s0wC5N 6TQ9DWHi4fe9G+fnqQA3sV8grrXGDd8+5xl5Kcka+JIecXHQJdQ8BW/YWdCx7bxSSXuw vCYG8aT/2qvqyfbJj+oe0vrCVjfKVbWJOJf7goV7UtsXhm9qnKXLlUXYkCy9BJrle20E QFSrYUpJwES2pmqLvkQYu0/b+HHSt4SG5sjOit+UA07Fo8Z4t2Az7/wjUyA0ZHAgF0Tq 6sBQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=A9db66j5jgBwQHfPYVkQHfIXD2LLsb4yznWteentD3Y=; b=fJmLhPGpU3KnDXhkUl+xme7O2inwYZQ9cOUavtDazgJE6woEhNEiBEGvFA7bIQKzB9 CUJY8ieedXaPrRfQQcvpUECTc6R+f0fxfKQbCOqeT61MUGrj3rMA/T5NJAeDqrpOXUWJ ywpRQ1sAe1LSYNay6YrT1oHV7bqWkon8MMvNeFgf2nsMqdPzUNmkNfkX/Io0O2NnU0mA RhXZHz5SKFxiwJn0/yzAQNTk2WY9c9MXuKR/vMeMEVlImbbnO8QaZw2JSAiPnEVwbnb7 2sf0xnqstXFAm1WTeRvs0FpevOS2V/OpqUzbX0PPLsjVDvQmi+P/qKuMpKt5bjPw6t7T Rmfg== X-Gm-Message-State: AOAM531wTbpj//hhd/zmHSE0AKts5tqKwHGKaBuOgO2z6/L1dNOheERi M4Y+6DIxlvmroTHPid8Wl2I= X-Google-Smtp-Source: ABdhPJwDUuGnIwIwClcyeH47ggGrqEBlLaCSAVS0nhhBdYJcxMb7TSNk5lmsKk5wPUo2x7+ZLev20Q== X-Received: by 2002:aa7:8b0b:0:b029:152:900d:2288 with SMTP id f11-20020aa78b0b0000b0290152900d2288mr2430480pfd.53.1603271774437; Wed, 21 Oct 2020 02:16:14 -0700 (PDT) Received: from VM-0-6-centos.localdomain ([119.28.90.140]) by smtp.gmail.com with ESMTPSA id x16sm1573002pff.14.2020.10.21.02.16.13 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Oct 2020 02:16:13 -0700 (PDT) From: Chunguang Xu X-Google-Original-From: Chunguang Xu To: tytso@mit.edu, adilger.kernel@dilger.ca Cc: linux-ext4@vger.kernel.org Subject: [PATCH 3/8] ext4: simplify the code of mb_find_order_for_block Date: Wed, 21 Oct 2020 17:15:23 +0800 Message-Id: <1603271728-7198-3-git-send-email-brookxu@tencent.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1603271728-7198-1-git-send-email-brookxu@tencent.com> References: <1603271728-7198-1-git-send-email-brookxu@tencent.com> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Chunguang Xu The code of mb_find_order_for_block is a bit obscure, but we can simplify it with mb_find_buddy(), make the code more concise. Signed-off-by: Chunguang Xu Reviewed-by: Andreas Dilger --- fs/ext4/mballoc.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 22301f3..2efb489 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -1289,22 +1289,18 @@ static void ext4_mb_unload_buddy(struct ext4_buddy *e4b) static int mb_find_order_for_block(struct ext4_buddy *e4b, int block) { - int order = 1; - int bb_incr = 1 << (e4b->bd_blkbits - 1); + int order = 1, max; void *bb; BUG_ON(e4b->bd_bitmap == e4b->bd_buddy); BUG_ON(block >= (1 << (e4b->bd_blkbits + 3))); - bb = e4b->bd_buddy; while (order <= e4b->bd_blkbits + 1) { - block = block >> 1; - if (!mb_test_bit(block, bb)) { + bb = mb_find_buddy(e4b, order, &max); + if (!mb_test_bit(block >> order, bb)) { /* this block is part of buddy of order 'order' */ return order; } - bb += bb_incr; - bb_incr >>= 1; order++; } return 0;