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 D6A62C433EF for ; Sat, 9 Apr 2022 06:44:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240180AbiDIGqI (ORCPT ); Sat, 9 Apr 2022 02:46:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240160AbiDIGqG (ORCPT ); Sat, 9 Apr 2022 02:46:06 -0400 Received: from mail-pg1-x52a.google.com (mail-pg1-x52a.google.com [IPv6:2607:f8b0:4864:20::52a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 08223B6E5D for ; Fri, 8 Apr 2022 23:44:00 -0700 (PDT) Received: by mail-pg1-x52a.google.com with SMTP id r66so9642383pgr.3 for ; Fri, 08 Apr 2022 23:44:00 -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=4KIbEhpDOtCyioS8BZF5p0mGW/6SLKhNyk9CSQ+cWmo=; b=mJomCgJeV+RXmlPTrKz6qrQhrHm7UDKRrcrKS4fB3ekDBuMvYloc6N3zmoewCRpve5 5wL2KDqW8Z+tm6tNzomwdJaRht0Ve91sWusE4dVKDHUDO7qYsjj+FJxjENUtyF7aeBAn dlxb86l3upJFsQhUVQzQHMwAnzbOq3hpu68G8h/vPyJhHFbsDHrlvpzXBgmB8YrMsUU5 vEnxIy4If3++IMbF512A0INdexqm6swj5Y83/EA90VybgBNxHF6AGuIGFQIKy/ogAVrY Fn7I8qbZ/6vMDoiFS2le7qfO1qviRbm+GcB25jK+buDGEz4Q8WoecYXCA5GlPJ+0QAlK 9Lcg== 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=4KIbEhpDOtCyioS8BZF5p0mGW/6SLKhNyk9CSQ+cWmo=; b=a6awTWHAcypRlzHH+g1T0aDWG/9ujQkCY/HOfuu9iTveIm96UK2WiFYYZU6ss5bSNR IcW1UxTZ30WYun69HFW3vKkGfK35rUnEqg+nXX4J+blqkewewdNHYehojirWesgowCWL fZjlS25pHABUDjrvmvGeiRx+0QlVWwW1sevG6N5hejhimpQBWaOxDnrvk15WTaYLo3Z2 9IChjM1fXC9GEbwNkbbb79fqm3wHDrSie6G1yBhuEf/tpYoIXs0FWIwx6Ii5lVl5B5BC ds8KjicFiXdvM3dBq4yQ/vYwELS3LoOEDTOHg9XBPRn/ThHsKIEkE2f8Gmpw/sUA3Rqe 3VPQ== X-Gm-Message-State: AOAM531+rhM6xxN2Fl3YI2Fd5Zpz/7x0POSqWlms9TXyrTsVeFt90JTD AEt+JyjZ9oUvtakjHGu5HPPEpEhJbCwl3je3W33mKw== X-Google-Smtp-Source: ABdhPJxoI+Rt3FuHlytPnMV9pwghZ6eRumL6W/khQzhcnTwilPXXMAY9cLvkEbBH/0UBAvxjMbxqY66yaPmjd4OXrpc= X-Received: by 2002:a63:3e8d:0:b0:398:5222:3a3 with SMTP id l135-20020a633e8d000000b00398522203a3mr18742608pga.561.1649486639371; Fri, 08 Apr 2022 23:43:59 -0700 (PDT) MIME-Version: 1.0 References: <20220408045743.1432968-1-yosryahmed@google.com> <20220408045743.1432968-3-yosryahmed@google.com> In-Reply-To: From: Yosry Ahmed Date: Fri, 8 Apr 2022 23:43:23 -0700 Message-ID: Subject: Re: [PATCH v3 2/4] selftests: cgroup: return the errno of write() in cg_write() on failure To: Roman Gushchin 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 , =?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" Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Fri, Apr 8, 2022 at 6:44 PM Roman Gushchin wrote: > > 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! Thanks a lot for reviewing it! I would appreciate it if you still took a look at the v4 version of this patch when I send it (probably early next week) as it's significantly different and includes changes to cg_read() and read_text() as well.