From patchwork Mon Nov 12 09:56:22 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Valente X-Patchwork-Id: 10678393 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 3C5E813AD for ; Mon, 12 Nov 2018 09:57:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2B61929F61 for ; Mon, 12 Nov 2018 09:57:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1DE5629F63; Mon, 12 Nov 2018 09:57:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id AEE0629F61 for ; Mon, 12 Nov 2018 09:57:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728854AbeKLTtl (ORCPT ); Mon, 12 Nov 2018 14:49:41 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:39591 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728268AbeKLTth (ORCPT ); Mon, 12 Nov 2018 14:49:37 -0500 Received: by mail-wm1-f65.google.com with SMTP id u13-v6so7486438wmc.4 for ; Mon, 12 Nov 2018 01:57:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=rpZR9mJwWH7OFtYLISHMCJG8f05AVkaLjpshd/8XLBg=; b=QDGg0Xfc28PGvnVlOCCcIqTsT8u+2STJ/BRHsU4TWNb0Qf39eUTzZBIPZWewRac+F9 r48HnFML9ikjsTAzSxVkv0tFmaCQtYLBMHy0CbrhczPcXAlEm1vn9O3ROOQfl4KxKeZt qrhsIG/0OD+gZ8HfdS87YYirC8OfV4zYGI4ck= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=rpZR9mJwWH7OFtYLISHMCJG8f05AVkaLjpshd/8XLBg=; b=pWoMB3uenJD8dXdUpnUq+C/AyOYdU8FJJCxpk7PiCA4BVqgOC3OR6fnJVa25TneFJW gM2BSDksYrsIXu/rS4yXE24Bdqm58j02vDu1gs5QJ6rYijm0Rd8fZD33KXExIykKd1eS HGM4vwG8DDNboxOFi6fdrFj+tAvuQhV413natc/8Juc3vPj7HBNZMyY9jMVu3BwUv6+Z rvY2y1hNQkBsZ+H+znXfJTORQ5LGRznbDI84OjP1wyC73g7xW/ZiXFgJm3moxJZZCIpl gvH/6CjyztBWmZA8Mre90qHw+XXPA511nO0FabZin0QT69QRZaEMEzeQBZqxQxTnFhy9 Kx6w== X-Gm-Message-State: AGRZ1gLDS0dPm0mTCmBmSrxBQbYOcJ1dLTfpO6Midniwj+YBpH2TxDHe dtB6KlgGf4zpGNagrLfP+HvOZg== X-Google-Smtp-Source: AJdET5eWLeJkszgxQtsLss1OSpAsy7RqDKp6DgrqNS+c3cAOGNvX8LTc+ygXS4wYZVvjQxFVOOjuEA== X-Received: by 2002:a1c:2097:: with SMTP id g145-v6mr6949615wmg.57.1542016627706; Mon, 12 Nov 2018 01:57:07 -0800 (PST) Received: from localhost.localdomain ([93.68.220.21]) by smtp.gmail.com with ESMTPSA id r14-v6sm21273089wro.8.2018.11.12.01.57.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 12 Nov 2018 01:57:07 -0800 (PST) From: Paolo Valente To: Jens Axboe , Greg Kroah-Hartman , Tejun Heo , Li Zefan , Angelo Ruocco , Dennis Zhou , Josef Bacik , Liu Bo , Bart Van Assche , Johannes Weiner Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ulf.hansson@linaro.org, linus.walleij@linaro.org, broonie@kernel.org, bfq-iosched@googlegroups.com, oleksandr@natalenko.name, cgroups@vger.kernel.org, linux-doc@vger.kernel.org, Jonathan Corbet , Paolo Valente Subject: [PATCH 02/12] cgroup: add hook seq_show_cft with also the owning cftype as parameter Date: Mon, 12 Nov 2018 10:56:22 +0100 Message-Id: <20181112095632.69114-3-paolo.valente@linaro.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20181112095632.69114-1-paolo.valente@linaro.org> References: <20181112095632.69114-1-paolo.valente@linaro.org> Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The current implementation of the seq_show hook in the cftype struct has only, as parameters, the seq_file to write to and the arguments passed by the command line. Thus, the only way to retrieve the cftype that owns an instance of such hook function is by using the accessor in the seq_file itself. But in a future scenario where the same file may be shared by multiple cftypes, this accessor will point only to the first of the cftypes linked to the seq_file. It will then be impossible to access the cftype owning the seq_show function within the seq_show itself, unless such cftype is the first one. This commit adds an additional seq_show_cft hook that has as a formal parameter also the cftype that owns the function. Signed-off-by: Angelo Ruocco Signed-off-by: Paolo Valente --- include/linux/cgroup-defs.h | 3 ++- kernel/cgroup/cgroup.c | 15 +++++++++------ 2 files changed, 11 insertions(+), 7 deletions(-) diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 5e1694fe035b..7841db6e7fb3 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -543,8 +543,9 @@ struct cftype { */ s64 (*read_s64)(struct cgroup_subsys_state *css, struct cftype *cft); - /* generic seq_file read interface */ + /* generic seq_file read interfaces*/ int (*seq_show)(struct seq_file *sf, void *v); + int (*seq_show_cft)(struct seq_file *sf, struct cftype *cft, void *v); /* optional ops, implement all or none */ void *(*seq_start)(struct seq_file *sf, loff_t *ppos); diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 8b79318810ad..74012b61fe19 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1448,7 +1448,8 @@ static umode_t cgroup_file_mode(const struct cftype *cft) { umode_t mode = 0; - if (cft->read_u64 || cft->read_s64 || cft->seq_show) + if (cft->read_u64 || cft->read_s64 || cft->seq_show || + cft->seq_show_cft) mode |= S_IRUGO; if (cft->write_u64 || cft->write_s64 || cft->write) { @@ -3549,17 +3550,19 @@ static int cgroup_seqfile_show(struct seq_file *m, void *arg) { struct cftype *cft = seq_cft(m); struct cgroup_subsys_state *css = seq_css(m); + int ret = 0; if (cft->seq_show) - return cft->seq_show(m, arg); - - if (cft->read_u64) + ret = cft->seq_show(m, arg); + else if (cft->seq_show_cft) + ret = cft->seq_show_cft(m, cft, arg); + else if (cft->read_u64) seq_printf(m, "%llu\n", cft->read_u64(css, cft)); else if (cft->read_s64) seq_printf(m, "%lld\n", cft->read_s64(css, cft)); else - return -EINVAL; - return 0; + ret = -EINVAL; + return ret; } static struct kernfs_ops cgroup_kf_single_ops = {