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 A5DBCC4332F for ; Thu, 2 Nov 2023 17:58:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235073AbjKBR6n (ORCPT ); Thu, 2 Nov 2023 13:58:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43706 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345278AbjKBR6R (ORCPT ); Thu, 2 Nov 2023 13:58:17 -0400 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BAD24198 for ; Thu, 2 Nov 2023 10:58:12 -0700 (PDT) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-5a7af53bde4so17604317b3.0 for ; Thu, 02 Nov 2023 10:58:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1698947892; x=1699552692; darn=vger.kernel.org; h=to:from:subject:references:mime-version:message-id:in-reply-to:date :from:to:cc:subject:date:message-id:reply-to; bh=gQDO1z3HzTf9lqy8F57xj4IdkjAIJI4YmDCo/V9kva4=; b=3W7iaMIPuvUaKeYlP7mwPjF5hMihBjGyYmyG1XgN3UjeXdomAPaJrjxpmVOT7zxgbH pS6rRuE9sSNlNINxQAuX0ruABGrUmfu/+bu1q1gAeUkC2qR21K/aJaShq8EiNw3Lvxge xz/2jgbcH82CBXg5hJ9RQgoNmqScZe7p5CKg5iYWYkbNSknWKMqPMSpIqaaXdqAnks1H hAq8BTt/7C/DSkcuMktOmrosvbZA0CjDbj57dDoUBHXdV/SKl+PlI1K0SneetrBRCq0k a6VyRuBBZyl5o6ZoydVZ6zPjAuuvzq+JlttilJ0Nt1BGtPxIZdzdZgUVhdC7a2cd2k2h UJzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698947892; x=1699552692; h=to:from:subject:references:mime-version:message-id:in-reply-to:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=gQDO1z3HzTf9lqy8F57xj4IdkjAIJI4YmDCo/V9kva4=; b=cyXHUm52Z6YcHsmWI4IgZERQKW5IlvPRUJikecQo3r1FSCfIodGoRKQkSJLJTSMvPY Af1mY1A9pLHkdnHIXpLwIL/dJaQPsfOC8mzvRhEOlWulj22imGYVvWbJhqGADn1Ng6V9 uxXahlk1CsO/1Jtb6frFg1ezdbGz7uMlUz7GdJ5+X0uzE7ylyMkLgoB83abCRM/JYYA+ Ixop4UHNG0WdlQVLjBaBr4ZYlOj9vsA+BSo17U1+FTn5eFSohHnnrHtuN3KPrWMFK9ts on7hkYOCgLN6rPlIoEAsYMFSu7s4G4ZaZqb65QGIzEXjkmeb8UlFqmfPY8+W0IMu99L/ sTtQ== X-Gm-Message-State: AOJu0YwXqvmBcnEeOtr9kLhavX/I5z1RjFXPcnlDqxXesUUUDQSdlj+g ecPG6bIq/H9KWClAHcfukzafpdmAN5vO X-Google-Smtp-Source: AGHT+IGytIo9MZ59PK1OLFp7dn9lFWthEonyvFlsVlhUziFSusNeT7JmbqtkwXtkA5ufohMiFWyK8MJ6L7uX X-Received: from irogers.svl.corp.google.com ([2620:15c:2a3:200:bb34:df9c:836c:afca]) (user=irogers job=sendgmr) by 2002:a81:a14c:0:b0:59b:f138:c845 with SMTP id y73-20020a81a14c000000b0059bf138c845mr8439ywg.2.1698947891880; Thu, 02 Nov 2023 10:58:11 -0700 (PDT) Date: Thu, 2 Nov 2023 10:56:49 -0700 In-Reply-To: <20231102175735.2272696-1-irogers@google.com> Message-Id: <20231102175735.2272696-8-irogers@google.com> Mime-Version: 1.0 References: <20231102175735.2272696-1-irogers@google.com> X-Mailer: git-send-email 2.42.0.869.gea05f2083d-goog Subject: [PATCH v4 07/53] tools api fs: Avoid reading whole file for a 1 byte bool From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Ian Rogers , Adrian Hunter , Nick Terrell , Kan Liang , Andi Kleen , Kajol Jain , Athira Rajeev , Huacai Chen , Masami Hiramatsu , Vincent Whitchurch , "Steinar H. Gunderson" , Liam Howlett , Miguel Ojeda , Colin Ian King , Dmitrii Dolgov <9erthalion6@gmail.com>, Yang Jihong , Ming Wang , James Clark , K Prateek Nayak , Sean Christopherson , Leo Yan , Ravi Bangoria , German Gomez , Changbin Du , Paolo Bonzini , Li Dong , Sandipan Das , liuwenyu , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org sysfs__read_bool used the first byte from a fully read file into a string. It then looked at the first byte's value. Avoid doing this and just read the first byte. Signed-off-by: Ian Rogers --- tools/lib/api/fs/fs.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c index 496812b5f1d2..4c35a689d1fc 100644 --- a/tools/lib/api/fs/fs.c +++ b/tools/lib/api/fs/fs.c @@ -447,15 +447,16 @@ int sysfs__read_str(const char *entry, char **buf, size_t *sizep) int sysfs__read_bool(const char *entry, bool *value) { - char *buf; - size_t size; - int ret; + struct io io; + char bf[16]; + int ret = 0; - ret = sysfs__read_str(entry, &buf, &size); - if (ret < 0) - return ret; + io.fd = open(entry, O_RDONLY); + if (io.fd < 0) + return -errno; - switch (buf[0]) { + io__init(&io, io.fd, bf, sizeof(bf)); + switch (io__get_char(&io)) { case '1': case 'y': case 'Y': @@ -469,8 +470,7 @@ int sysfs__read_bool(const char *entry, bool *value) default: ret = -1; } - - free(buf); + close(io.fd); return ret; } -- 2.42.0.869.gea05f2083d-goog