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 1132EC433F5 for ; Sat, 9 Apr 2022 01:45:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240429AbiDIBrD (ORCPT ); Fri, 8 Apr 2022 21:47:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237880AbiDIBq5 (ORCPT ); Fri, 8 Apr 2022 21:46:57 -0400 Received: from out2.migadu.com (out2.migadu.com [188.165.223.204]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 433FD1F7; Fri, 8 Apr 2022 18:44:51 -0700 (PDT) Date: Fri, 8 Apr 2022 18:44:41 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1649468689; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=EaX3YgB0MApk9e4iRjxSG36z1CKX5ZmC5rxuBJrAT1I=; b=Vixq1q2y5mYbpP/5yFzoxE2p8QT9ZaBPN3CZfPu8M6T1WxyX2Cjs6NG7W2u0hgjxEtiPUj izMhNEY5Lzn7v6MQUq8o8CwUXAHtKC4iot5I1bpTC06nkdx20W/LUiIFrHhvmM0P7FoySf KafxyE6FxCpvxWU/7sY2sdL/I6w2VcA= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Roman Gushchin To: Yosry Ahmed Cc: Johannes Weiner , Michal Hocko , Shakeel Butt , Andrew Morton , David Rientjes , Tejun Heo , Zefan Li , Jonathan Corbet , Shuah Khan , Yu Zhao , Dave Hansen , Wei Xu , Greg Thelen , Chen Wandun , Vaibhav Jain , Michal =?iso-8859-1?Q?Koutn=FD?= , Tim Chen , cgroups@vger.kernel.org, linux-doc@vger.kernel.org, Linux Kernel Mailing List , Linux-MM , linux-kselftest@vger.kernel.org Subject: Re: [PATCH v3 2/4] selftests: cgroup: return the errno of write() in cg_write() on failure Message-ID: References: <20220408045743.1432968-1-yosryahmed@google.com> <20220408045743.1432968-3-yosryahmed@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 08, 2022 at 06:21:55PM -0700, Yosry Ahmed wrote: > 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. Ok, sounds good, please feel free to add my Acked-by: Roman Gushchin for the whole series. It looks really nice and ready for merging upstream to me. Thanks!