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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12DB9EB64D9 for ; Mon, 10 Jul 2023 07:39:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231264AbjGJHja (ORCPT ); Mon, 10 Jul 2023 03:39:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44140 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231322AbjGJHjZ (ORCPT ); Mon, 10 Jul 2023 03:39:25 -0400 Received: from mail-oi1-x22e.google.com (mail-oi1-x22e.google.com [IPv6:2607:f8b0:4864:20::22e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 642C4F4 for ; Mon, 10 Jul 2023 00:39:08 -0700 (PDT) Received: by mail-oi1-x22e.google.com with SMTP id 5614622812f47-3a1e6022b93so3214456b6e.1 for ; Mon, 10 Jul 2023 00:39:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1688974747; x=1691566747; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=nylNd4bJypqjy2p+mIjX7+lH56E0VvWsXGVw57XSk4s=; b=OZV5e6X85cMz8lstlN5z4lDR4f9EVfhUISluyAD1bMUMFNGBNEe2n/U1bxS+AnNDN/ Tb2JYyz1IyFaCCnPpVnCpvk5jVwaGpDInbvV0mIuaI+M4vTvWTcnuyEqyiEMVkNyXTZD 3Tz3BHIKy0uFm4Rhqh2X+ZWquLnT8ZVk6ELdS4RJtNpxWrcPpKjE3M++9Wwkg6GikQjx CW+HmyaO9PMaJlS7G7xQrrhExKMWpP3/ROvzwUAMBxv97jlGuUSLG92QhUU32DoYkql+ 28sGW10aQBzkhFqPR3Eq0Zs3TdZD1I+FaVWN0nmg+QgUk+DmRZfaHvtRhIAxEh8Vt33l wYIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688974747; x=1691566747; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=nylNd4bJypqjy2p+mIjX7+lH56E0VvWsXGVw57XSk4s=; b=FscUWeSHb1qvyFGAf7kM6C8Rjkom43XNG9XCSILZzDvradnb1R+CSJgKXfsCJXSl8g rDWtRC30ZkriWkkesCG2hCch9sWycMssRyddMPpSTfWuylgLxikWmJ6RommBZqEBAOos ds9wg7sdX6dmjo5NgNGdCMmnztr7KLwoTF5XnQcJ7q8UKWZw2NnETv9CEafJtroViicY RLziB5i3R7gkpe2qQfDLOjtzzsXh7rtdj1uq+p2NdB840KrxCAOEufpMbDr531bTdagG gBEWej7O6eZj8Y/o9RAd5+oQu6aAGcE9kamP3Fbfp7Op9nJF8E9YWEExYUei8QLa86hp K9Vw== X-Gm-Message-State: ABy/qLZdlcXUCUan/ynxM1TRrDnJePyniBEgrtntpbhmIVFOZR8KlBAl j+B00lCILF73S28qpJuKcPLM5sEWBRE= X-Google-Smtp-Source: APBJJlHbIXs5YdWo0jHlQBb/TaAyGsm319HHwbaGco+P3H2xoPcTXP9B03R5HOdngBmrnSQ7KhrYmA== X-Received: by 2002:a05:6358:2794:b0:133:7c4:e752 with SMTP id l20-20020a056358279400b0013307c4e752mr13392849rwb.26.1688974747335; Mon, 10 Jul 2023 00:39:07 -0700 (PDT) Received: from localhost ([156.236.96.165]) by smtp.gmail.com with ESMTPSA id c1-20020aa781c1000000b0067eb174cb9asm6488392pfn.136.2023.07.10.00.39.05 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Mon, 10 Jul 2023 00:39:07 -0700 (PDT) Date: Mon, 10 Jul 2023 15:48:03 +0800 From: Yue Hu To: Chunhai Guo Cc: xiang@kernel.org, chao@kernel.org, linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org, huyue2@coolpad.com Subject: Re: [PATCH] erofs: avoid unnecessary loops in z_erofs_pcluster_readmore() when read page beyond EOF Message-ID: <20230710154803.00004047.zbestahu@gmail.com> In-Reply-To: <20230710042531.28761-1-guochunhai@vivo.com> References: <20230710042531.28761-1-guochunhai@vivo.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 10 Jul 2023 12:25:31 +0800 Chunhai Guo wrote: > z_erofs_pcluster_readmore() may take a long time to loop when the page > offset is large enough, which is unnecessary should be prevented. > For example, when the following case is encountered, it will loop 4691368 > times, taking about 27 seconds. > - offset = 19217289215 > - inode_size = 1442672 > > Signed-off-by: Chunhai Guo > --- > fs/erofs/zdata.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c > index 5f1890e309c6..d9a0763f4595 100644 > --- a/fs/erofs/zdata.c > +++ b/fs/erofs/zdata.c > @@ -1841,7 +1841,7 @@ static void z_erofs_pcluster_readmore(struct z_erofs_decompress_frontend *f, > } > > cur = map->m_la + map->m_llen - 1; > - while (cur >= end) { > + while ((cur >= end) && (cur < i_size_read(inode))) { > pgoff_t index = cur >> PAGE_SHIFT; > struct page *page; > Reviewed-by: Yue Hu