From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-6.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 7869C7D08E for ; Mon, 12 Nov 2018 09:58:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727156AbeKLTtv (ORCPT ); Mon, 12 Nov 2018 14:49:51 -0500 Received: from mail-wr1-f68.google.com ([209.85.221.68]:39624 "EHLO mail-wr1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729238AbeKLTtv (ORCPT ); Mon, 12 Nov 2018 14:49:51 -0500 Received: by mail-wr1-f68.google.com with SMTP id b13so8549224wrx.6 for ; Mon, 12 Nov 2018 01:57:21 -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=z1yDznB1zlUn9X3/WRtGxgozB4Whpg1+Jm0y+uUAhQs=; b=PyZ8gOJocogy3BEEQogAOEoynZMxE8x1fvBu0cP2+n30x2NDzxjSXsAPqPzS7QF2yn 559MfbGKyuGBpBtaanAwzOoQhFxdw4OpTCdGb2uaAZpuWQhrfq2eoWDkvEvCAEIUZ6/X Pmr2XAYw4kpma6U7p99Xbla+MYZenfrHl3AVM= 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=z1yDznB1zlUn9X3/WRtGxgozB4Whpg1+Jm0y+uUAhQs=; b=lEAGVz7aW7ms8uyvHRMtmBNiRmWDvjhQCJk4WEnrElooqoTLLweAHB2QDaxqqpkhfA eOOaL5HUDHyinW/sSaLF7dlLj51e0NW+nlJWkPF1hVpvLlVQsM2Og2XGU6pgx8cqieq5 rWy9fuMjfKAlYM3qdeeivPK8kG2jTenAzy2Q9SUtqp7LCezR/e2eRqpfiiXu+GLuCLJV 4SkvvV7ECVVcqSA9NN0qT+ryFTfz8yMtCFeqDoBstCkt3HVyXjf3j9uZQKabUeG5KqJD qlYYti1tijZpfAinKRqGP2dozBP0A5eVRgXBjuVrynQC39zglrrgLw5zPXQQcJedfq1U zIGA== X-Gm-Message-State: AGRZ1gJBctEm9tS9neMmcyqKTAE3u7Cf5IpI6pyO5hbZU6wxxiqXgoTk 7iXYRw26AH/F9s7M6rO3Qwq2qQ== X-Google-Smtp-Source: AJdET5cNricL6ewA3bg6OKKhOdQerlzg7sQ1hwsx5lzQkbAPiYr3jhHML+GAlyn5W5yKLyQBSw+HkQ== X-Received: by 2002:a5d:4a11:: with SMTP id m17-v6mr273341wrq.259.1542016640333; Mon, 12 Nov 2018 01:57:20 -0800 (PST) Received: from localhost.localdomain ([93.68.220.21]) by smtp.gmail.com with ESMTPSA id r14-v6sm21273089wro.8.2018.11.12.01.57.18 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 12 Nov 2018 01:57:19 -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 07/12] cgroup: make all functions of all cftypes be invoked Date: Mon, 12 Nov 2018 10:56:27 +0100 Message-Id: <20181112095632.69114-8-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-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org From: Angelo Ruocco When two or more policies share a file their respective cftypes are linked together. The allowed operations on those files are: open, release, write and show, mapped to the functions defined in the cftypes. This commit makes the cgroup core invoke, whenever one of those operations is requested, the respective function of all the cftypes linked together. Signed-off-by: Angelo Ruocco Signed-off-by: Paolo Valente --- kernel/cgroup/cgroup.c | 181 ++++++++++++++++++++++++++++++++++++------------- 1 file changed, 132 insertions(+), 49 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index e3cc437669a8..6d4cfd6395ec 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -3481,66 +3481,107 @@ static int cgroup_cpu_pressure_show(struct seq_file *seq, void *v) static int cgroup_file_open(struct kernfs_open_file *of) { struct cftype *cft = of->kn->priv; + struct cftype *n; + int ret = 0; + list_for_each_cft(cft, n) { + if (cft->open) + ret = cft->open(of); + /* + * If there has been an error with the open function of one of + * the cft associated with the file, we call the release + * function of all the cftype associated to cft whose open + * function succeded. + */ + if (ret) { + struct cftype *c = of->kn->priv; + struct cftype *n; + + list_for_each_cft(c, n) { + if (cft == c) + break; + if (c->release) + c->release(of); + } + break; + } + } - if (cft->open) - return cft->open(of); - return 0; + return ret; } static void cgroup_file_release(struct kernfs_open_file *of) { struct cftype *cft = of->kn->priv; + struct cftype *n; - if (cft->release) - cft->release(of); + list_for_each_cft(cft, n) + if (cft->release) + cft->release(of); } +/* + * Call all the write functions of the cftypes associated with the file. + * + * When a write fails, don't keep trying to write into the file via the write + * functions of the other cftypes associated with it. + */ static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf, size_t nbytes, loff_t off) { struct cgroup_namespace *ns = current->nsproxy->cgroup_ns; struct cgroup *cgrp = of->kn->parent->priv; struct cftype *cft = of->kn->priv; + struct cftype *n; struct cgroup_subsys_state *css; - int ret; + int ret = 0; - /* - * If namespaces are delegation boundaries, disallow writes to - * files in an non-init namespace root from inside the namespace - * except for the files explicitly marked delegatable - - * cgroup.procs and cgroup.subtree_control. - */ - if ((cgrp->root->flags & CGRP_ROOT_NS_DELEGATE) && - !(cft->flags & CFTYPE_NS_DELEGATABLE) && - ns != &init_cgroup_ns && ns->root_cset->dfl_cgrp == cgrp) - return -EPERM; + list_for_each_cft(cft, n) { + /* + * If namespaces are delegation boundaries, disallow writes to + * files in an non-init namespace root from inside the + * namespace except for the files explicitly marked + * delegatable - cgroup.procs and cgroup.subtree_control. + */ + if ((cgrp->root->flags & CGRP_ROOT_NS_DELEGATE) && + !(cft->flags & CFTYPE_NS_DELEGATABLE) && + ns != &init_cgroup_ns && ns->root_cset->dfl_cgrp == cgrp) + return -EPERM; - if (cft->write) - return cft->write(of, buf, nbytes, off); + if (cft->write) { + ret = cft->write(of, buf, nbytes, off); - /* - * kernfs guarantees that a file isn't deleted with operations in - * flight, which means that the matching css is and stays alive and - * doesn't need to be pinned. The RCU locking is not necessary - * either. It's just for the convenience of using cgroup_css(). - */ - rcu_read_lock(); - css = cgroup_css(cgrp, cft->ss); - rcu_read_unlock(); + if (ret) + break; + continue; + } - if (cft->write_u64) { - unsigned long long v; - ret = kstrtoull(buf, 0, &v); - if (!ret) - ret = cft->write_u64(css, cft, v); - } else if (cft->write_s64) { - long long v; - ret = kstrtoll(buf, 0, &v); - if (!ret) - ret = cft->write_s64(css, cft, v); - } else { - ret = -EINVAL; + /* + * kernfs guarantees that a file isn't deleted with operations + * in flight, which means that the matching css is and stays + * alive and doesn't need to be pinned. The RCU locking is not + * necessary either. It's just for the convenience of using + * cgroup_css(). + */ + rcu_read_lock(); + css = cgroup_css(cgrp, cft->ss); + rcu_read_unlock(); + + if (cft->write_u64) { + unsigned long long v; + + ret = kstrtoull(buf, 0, &v); + if (!ret) + ret = cft->write_u64(css, cft, v); + } else if (cft->write_s64) { + long long v; + + ret = kstrtoll(buf, 0, &v); + if (!ret) + ret = cft->write_s64(css, cft, v); + } else { + return -EINVAL; + } } return ret ?: nbytes; @@ -3562,22 +3603,64 @@ static void cgroup_seqfile_stop(struct seq_file *seq, void *v) seq_cft(seq)->seq_stop(seq, v); } +/* + * A file shared by more cftypes may be showing different values. In that case + * call all the show functions and print the name of the owner that defined + * them. + */ static int cgroup_seqfile_show(struct seq_file *m, void *arg) { struct cftype *cft = seq_cft(m); + struct cftype *n; struct cgroup_subsys_state *css = seq_css(m); + char *first_seqshow_str = NULL; + size_t first_str_size = 0; + size_t current_str_size = 0; int ret = 0; - if (cft->seq_show) - 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 - ret = -EINVAL; + list_for_each_cft(cft, n) { + if (cft->seq_show) { + ret = cft->seq_show(m, arg); + if (ret) + break; + } else if (cft->seq_show_cft) { + ret = cft->seq_show_cft(m, cft, arg); + if (ret) + break; + } 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 { + ret = -EINVAL; + break; + } + current_str_size = m->count - current_str_size; + + if (first_seqshow_str == NULL) { + first_seqshow_str = kmalloc(m->size, GFP_KERNEL); + first_str_size = m->count; + strcpy(first_seqshow_str, m->buf); + first_str_size = m->count; + } else if (strcmp(first_seqshow_str, + m->buf + m->count - current_str_size)) { + first_str_size = -1; + } + + if (current_str_size) { + seq_printf(m, " - %s\n", cft->owner_name); + current_str_size = m->count; + } + } + + /* + * If all the cft->seqfile_show/read are equal, truncate the + * output of the seqfile to the length of the first string. + */ + if (first_str_size != -1) + m->count = first_str_size; + + kfree(first_seqshow_str); return ret; } -- 2.16.1