From patchwork Mon Oct 19 09:02:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: brookxu X-Patchwork-Id: 1384105 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=FVn1TQ4C; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CF9kv0b2Kz9sSG for ; Mon, 19 Oct 2020 20:02:47 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729795AbgJSJCq (ORCPT ); Mon, 19 Oct 2020 05:02:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46770 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728441AbgJSJCq (ORCPT ); Mon, 19 Oct 2020 05:02:46 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27B7CC0613CE for ; Mon, 19 Oct 2020 02:02:45 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id v12so4642500ply.12 for ; Mon, 19 Oct 2020 02:02:45 -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=r3sZO1kwTuy79OCycDSs7UKZ99C2F8Th3DIIU2eTHdI=; b=FVn1TQ4CtngXb02CEjN5RDiC+gW/CfaqGUl059aeFxN/t+sm2DHHeWAMkQuawAe06x E6EH8sEWmqAaXHs48A0NFDYQGI0CbQJ7X9KdtEFc+/Ct5PBwIk/PvSqmy3Ttkox13X9S tu4/OZ2Jol+FxjjMHlnMEAbTPSVwOX1V6Weoea8x3dWra8ZToJIITa1fyZESPqDOxnGH G7nQ6IgHktjmiamQxSW8iixB+gnTH3vAYqezrwHWRl15UtR4FVBcLMM0Tt8RCP2NbOFd 5pj1BeUvU6Uc9aYTme9UU6rp0dbjIIl82bCi4zxvLbmcLPJZPrulyALwsLMD0e/0AL+W EBWA== 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=r3sZO1kwTuy79OCycDSs7UKZ99C2F8Th3DIIU2eTHdI=; b=PcNoQHDi03IZCx4fmcvKVNqXZLdH5ia058kjqmySzm6hxsJKwBvxKx6WCJMG7G5shc 0YJFVTaojVMujDZabCRdvWL1A1NnVZFYUvCOm1mPRe6ErdQ9Qmr8CbujBko2W+HuwyjJ cNbopcdhPggS5IxZI2f1gqUtDpOQqRp/P5lnM6hIP3UBK7ptB19f6y9jIBKLntuyT85M uADzRwUQUF21nSeMc8ygE9fz+nxRbqaR/tbfpYvywYvlMoCHIMv9CY6raz6R9sYoWL5G pvEpdp2Lyk6/pll8D3jYuDJCuoDcakKpsGW1BVxwMXUPeeaaoi/1nNKVY+8QH4/sqErS yyFw== X-Gm-Message-State: AOAM5309M4t9I+EcRz7AB0BKucH5nM3sfojL93I2Tm1Prm2MocsJxv1S QSepSph3sl6ogAFrF20p82I= X-Google-Smtp-Source: ABdhPJwjX7GgwxrJTEEHJRBnRXaSFS9Hoy5sVlY/lpZcJCnvqNmvu5qYFrROWLX/neF62lpORu8e0A== X-Received: by 2002:a17:902:8341:b029:d4:e3fa:e464 with SMTP id z1-20020a1709028341b02900d4e3fae464mr16238082pln.66.1603098164777; Mon, 19 Oct 2020 02:02:44 -0700 (PDT) Received: from VM-0-6-centos.localdomain ([119.28.90.140]) by smtp.gmail.com with ESMTPSA id 14sm11422880pjn.48.2020.10.19.02.02.43 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 19 Oct 2020 02:02:44 -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 v2 3/8] ext4: simplify the code of mb_find_order_for_block Date: Mon, 19 Oct 2020 17:02:33 +0800 Message-Id: <1603098158-30406-3-git-send-email-brookxu@tencent.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1603098158-30406-1-git-send-email-brookxu@tencent.com> References: <1603098158-30406-1-git-send-email-brookxu@tencent.com> Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org 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 --- 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 03337c8..56075ce 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;