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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 B2AA5C2D0A3 for ; Sun, 1 Nov 2020 21:04:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0F64822246 for ; Sun, 1 Nov 2020 21:04:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F64822246 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=perches.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4C1A06B005C; Sun, 1 Nov 2020 16:04:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4725A6B005D; Sun, 1 Nov 2020 16:04:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3870D6B006E; Sun, 1 Nov 2020 16:04:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0207.hostedemail.com [216.40.44.207]) by kanga.kvack.org (Postfix) with ESMTP id 2231F6B005C for ; Sun, 1 Nov 2020 16:04:40 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id E5F9F181AEF1A for ; Sun, 1 Nov 2020 21:04:39 +0000 (UTC) X-FDA: 77437078278.20.touch76_17054cb272aa Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin20.hostedemail.com (Postfix) with ESMTP id BFC23180C07A3 for ; Sun, 1 Nov 2020 21:04:39 +0000 (UTC) X-HE-Tag: touch76_17054cb272aa X-Filterd-Recvd-Size: 3851 Received: from smtprelay.hostedemail.com (smtprelay0030.hostedemail.com [216.40.44.30]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Sun, 1 Nov 2020 21:04:39 +0000 (UTC) Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay03.hostedemail.com (Postfix) with ESMTP id 2B96E837F24A; Sun, 1 Nov 2020 21:04:39 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: fork10_3615e0f272aa X-Filterd-Recvd-Size: 2699 Received: from XPS-9350.home (unknown [47.151.133.149]) (Authenticated sender: joe@perches.com) by omf01.hostedemail.com (Postfix) with ESMTPA; Sun, 1 Nov 2020 21:04:37 +0000 (UTC) Message-ID: <616b92af9378e9f9697555074bba1e377450477f.camel@perches.com> Subject: Re: [PATCH 4/5] mm: shmem: Convert shmem_enabled_show to use sysfs_emit_at From: Joe Perches To: Matthew Wilcox Cc: Hugh Dickins , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Date: Sun, 01 Nov 2020 13:04:35 -0800 In-Reply-To: <20201101204834.GF27442@casper.infradead.org> References: <20201101204834.GF27442@casper.infradead.org> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.38.1-1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, 2020-11-01 at 20:48 +0000, Matthew Wilcox wrote: > On Sun, Nov 01, 2020 at 12:12:51PM -0800, Joe Perches wrote: > > @@ -4024,7 +4024,7 @@ int __init shmem_init(void) > > =A0 > >=20 > > =A0#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SYSFS) > > =A0static ssize_t shmem_enabled_show(struct kobject *kobj, > > - struct kobj_attribute *attr, char *buf) > > + struct kobj_attribute *attr, char *buf) > > =A0{ > > =A0 static const int values[] =3D { > > =A0 SHMEM_HUGE_ALWAYS, >=20 > Why? why what? =20 > > @@ -4034,16 +4034,19 @@ static ssize_t shmem_enabled_show(struct kobj= ect *kobj, > > =A0 SHMEM_HUGE_DENY, > > =A0 SHMEM_HUGE_FORCE, > > =A0 }; > > - int i, count; > > - > > - for (i =3D 0, count =3D 0; i < ARRAY_SIZE(values); i++) { > > - const char *fmt =3D shmem_huge =3D=3D values[i] ? "[%s] " : "%s "; > > + int len =3D 0; > > + int i; >=20 > Better: > int i, len =3D 0; I generally disagree as I think it better to have each declaration on an individual line. > > - count +=3D sprintf(buf + count, fmt, > > - shmem_format_huge(values[i])); > > + for (i =3D 0; i < ARRAY_SIZE(values); i++) { > > + len +=3D sysfs_emit_at(buf, len, > > + shmem_huge =3D=3D values[i] ? "%s[%s]" : "%s%s", > > + i ? " " : "", > > + shmem_format_huge(values[i])); >=20 > This is ... complicated. I thought the point of doing all the sysfs_em= it > stuff was to simplify things. The removal of fmt allows the format and argument to be __printf verified= . Indirected formats do not generally allow that. And using sysfs_emit is not really intended to simplify output code, it's used to make sure there isn't a overflow of the PAGE_SIZE output buf when using sprintf/snprintf.