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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 15D60C433EF for ; Sat, 9 Apr 2022 01:22:34 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 528DD6B0071; Fri, 8 Apr 2022 21:22:34 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4D7496B0073; Fri, 8 Apr 2022 21:22:34 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 379316B0074; Fri, 8 Apr 2022 21:22:34 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0167.hostedemail.com [216.40.44.167]) by kanga.kvack.org (Postfix) with ESMTP id 2860C6B0071 for ; Fri, 8 Apr 2022 21:22:34 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id B0CBBAA19F for ; Sat, 9 Apr 2022 01:22:33 +0000 (UTC) X-FDA: 79335590586.22.246FF85 Received: from mail-pj1-f47.google.com (mail-pj1-f47.google.com [209.85.216.47]) by imf29.hostedemail.com (Postfix) with ESMTP id 0CFCE120005 for ; Sat, 9 Apr 2022 01:22:32 +0000 (UTC) Received: by mail-pj1-f47.google.com with SMTP id h23-20020a17090a051700b001c9c1dd3acbso11282570pjh.3 for ; Fri, 08 Apr 2022 18:22:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=I0F2P2ML/pBi824KYgTw5KU1Y45bJmTHodkEFj/msPE=; b=rnIIkb90V9I9bcpVMa5/w0cTf4Gar8GVFDke+JSlU2hEHFp3OsRcTAqk7dfPeFG8tF dDExEmFCxiNoVK2EMa1ylHUlmv7DSThq6XmiX4TNJLDsXoKoUElD/mYy3ENP5lUCX6Cm L0cqaNurq1CWtLL/S3jZRhd8I253TJx1CfvGJLV8g4b2GyGGXfVeqwYyZcNtCYqWoaTJ rljgm3m6gGpplEG1geT3BvdWqZgCrGRUG3e99TyERwVqbDQLP1p54prwkHbmcNQHKk4J 2yNkYps6CqNhbHgl2xIZXaESlcelXNqaHtoVajN8GB4WEs0RS7UrQYqzpjddvSoSRqdi sZ6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=I0F2P2ML/pBi824KYgTw5KU1Y45bJmTHodkEFj/msPE=; b=zQ8dgzdcXCkbCJb90mfn5VQ39xJ6d70+oeX7IsVzpnYE+jiJCko21J8IgyqisqC9Lj rg+4yEhdZ/CrnYEBAvZhojbG1vGjXouUIQ9T/1ujrUL/vVNVTO71KwkCbVp+G1hfaJX3 HxYwn3fCNxxFlU+nYelnAS5OiH1FR5hR3VM/Yh8aJ2xjjDWZSRS2lmD8NUOf8Rb6QhlG M3ohPvLBw5LQ1IWXKTbFrJ0RNNevPJ7YHc/QVSdHWOTyDmhrNVhD43hM1HO9debC/tCt 9WCUxl11HrO9NBoZ1o28p0c8LT6+b/XGOCVexmcigBPGqvlr+9xcey2IcqyR66Ge8EbS h/iA== X-Gm-Message-State: AOAM533/CC7/gU+7VMVhUkfNGBHBVJ8eqaWPbTd+r9Gy1eUqxYKnG1D4 /xzcUBplbX/QD9DNq3qUupY2BUNIw2ifnusuJxFVSA== X-Google-Smtp-Source: ABdhPJyJCUjj5J7R135dzSPAdcxIjuPzJmPklzIABqKF59nyK/U0cF2KfJdhnRS2Ev/Kou5gxn1s4+XTYi7R+kW7BNM= X-Received: by 2002:a17:90b:3886:b0:1c7:c935:4447 with SMTP id mu6-20020a17090b388600b001c7c9354447mr25107776pjb.196.1649467351747; Fri, 08 Apr 2022 18:22:31 -0700 (PDT) MIME-Version: 1.0 References: <20220408045743.1432968-1-yosryahmed@google.com> <20220408045743.1432968-3-yosryahmed@google.com> In-Reply-To: <20220408045743.1432968-3-yosryahmed@google.com> From: Yosry Ahmed Date: Fri, 8 Apr 2022 18:21:55 -0700 Message-ID: Subject: Re: [PATCH v3 2/4] selftests: cgroup: return the errno of write() in cg_write() on failure To: Johannes Weiner , Michal Hocko , Shakeel Butt , Andrew Morton , Roman Gushchin Cc: David Rientjes , Tejun Heo , Zefan Li , Jonathan Corbet , Shuah Khan , Yu Zhao , Dave Hansen , Wei Xu , Greg Thelen , Chen Wandun , Vaibhav Jain , =?UTF-8?Q?Michal_Koutn=C3=BD?= , Tim Chen , cgroups@vger.kernel.org, linux-doc@vger.kernel.org, Linux Kernel Mailing List , Linux-MM , linux-kselftest@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Stat-Signature: awyu395t7ocfdsyhya8niye3rrh14chm Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=rnIIkb90; spf=pass (imf29.hostedemail.com: domain of yosryahmed@google.com designates 209.85.216.47 as permitted sender) smtp.mailfrom=yosryahmed@google.com; dmarc=pass (policy=reject) header.from=google.com X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 0CFCE120005 X-HE-Tag: 1649467352-179928 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 Thu, Apr 7, 2022 at 9:57 PM Yosry Ahmed wrote: > > Currently, cg_write() returns 0 on success and -1 on failure. Modify it > to return the errno of write() syscall when write() fails. > > Signed-off-by: Yosry Ahmed > --- > tools/testing/selftests/cgroup/cgroup_util.c | 32 +++++++++++--------- > 1 file changed, 17 insertions(+), 15 deletions(-) > > diff --git a/tools/testing/selftests/cgroup/cgroup_util.c b/tools/testing/selftests/cgroup/cgroup_util.c > index dbaa7aabbb4a..3b6bb09985fa 100644 > --- a/tools/testing/selftests/cgroup/cgroup_util.c > +++ b/tools/testing/selftests/cgroup/cgroup_util.c > @@ -38,23 +38,23 @@ static ssize_t read_text(const char *path, char *buf, size_t max_len) > return len; > } > > -static ssize_t write_text(const char *path, char *buf, ssize_t len) > +/* > + * Returns: > + * success -> 0 > + * open() failure -> -1 > + * write() failure -> errno > + */ > +static int write_text(const char *path, char *buf, ssize_t len) > { > - int fd; > + int fd, ret; > > fd = open(path, O_WRONLY | O_APPEND); > if (fd < 0) > return fd; > > - len = write(fd, buf, len); > - if (len < 0) { > - close(fd); > - return len; > - } > - > + ret = write(fd, buf, len) < 0 ? errno : 0; > close(fd); > - > - return len; > + return ret; > } > > char *cg_name(const char *root, const char *name) > @@ -177,17 +177,19 @@ long cg_read_lc(const char *cgroup, const char *control) > return cnt; > } > > +/* > + * Returns: > + * success -> 0 > + * open() failure -> -1 > + * write() failure -> errno > + */ > int cg_write(const char *cgroup, const char *control, char *buf) > { > char path[PATH_MAX]; > ssize_t len = strlen(buf); > > snprintf(path, sizeof(path), "%s/%s", cgroup, control); > - > - if (write_text(path, buf, len) == len) > - return 0; > - > - return -1; > + return write_text(path, buf, len); > } I have changed this in v4 to a cleaner implementation that either returns 0 on success or -errno on failure. I also made sure to check that the full buffer was being written, and updated cg_read() as well for the interface to be consistent. Will send out once the discussion on patch 1 in v3 reaches a consensus. > > int cg_find_unified_root(char *root, size_t len) > -- > 2.35.1.1178.g4f1659d476-goog >