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[2603:800c:1a02:1bae:a7fa:157f:969a:4cde]) by smtp.gmail.com with ESMTPSA id y14-20020a62ce0e000000b0053e66f57334sm6702256pfg.112.2022.09.23.10.31.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Sep 2022 10:32:00 -0700 (PDT) Sender: Tejun Heo Date: Fri, 23 Sep 2022 07:31:58 -1000 From: Tejun Heo To: Ming Lei Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, Marco Patalano , Muneendra , Michal =?iso-8859-1?Q?Koutn=FD?= Subject: [PATCH cgroup/for-6.1] cgroup: Make cgroup_get_from_id() prettier Message-ID: References: <20220923115119.2035603-1-ming.lei@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >From 7e1eb5437d3c3fdb61d45378579aab383cafc694 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 23 Sep 2022 07:23:06 -1000 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit After merging 836ac87d ("cgroup: fix cgroup_get_from_id") into for-6.1, its combination with two commits in for-6.1 - 4534dee9 ("cgroup: cgroup: Honor caller's cgroup NS when resolving cgroup id") and fa7e439c ("cgroup: Homogenize cgroup_get_from_id() return value") - makes the gotos in the error handling path too ugly while not adding anything of value. All that the gotos are saving is one extra kernfs_put() call. Let's remove the gotos and perform error returns directly. Signed-off-by: Tejun Heo Cc: Ming Lei Cc: Michal Koutný --- Hello, Ming, Michal, you guys' changes to cgroup_get_from_id() combine to make cgroup_get_from_id() a bit too ugly, so I applied the following patch to cgroup/for-6.1. Please take a look and lemme know if I broke anything. Thanks. kernel/cgroup/cgroup.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 0d93cd17548c..c1f1ef6090da 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6066,14 +6066,16 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) struct cgroup *cgroup_get_from_id(u64 id) { struct kernfs_node *kn; - struct cgroup *cgrp = NULL, *root_cgrp; + struct cgroup *cgrp, *root_cgrp; kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id); if (!kn) - goto out; + return ERR_PTR(-ENOENT); - if (kernfs_type(kn) != KERNFS_DIR) - goto put; + if (kernfs_type(kn) != KERNFS_DIR) { + kernfs_put(kn); + return ERR_PTR(-ENOENT); + } rcu_read_lock(); @@ -6082,21 +6084,20 @@ struct cgroup *cgroup_get_from_id(u64 id) cgrp = NULL; rcu_read_unlock(); -put: kernfs_put(kn); if (!cgrp) - goto out; + return ERR_PTR(-ENOENT); spin_lock_irq(&css_set_lock); root_cgrp = current_cgns_cgroup_from_root(&cgrp_dfl_root); spin_unlock_irq(&css_set_lock); if (!cgroup_is_descendant(cgrp, root_cgrp)) { cgroup_put(cgrp); - cgrp = NULL; + return ERR_PTR(-ENOENT); } -out: - return cgrp ?: ERR_PTR(-ENOENT); + + return cgrp; } EXPORT_SYMBOL_GPL(cgroup_get_from_id); -- 2.37.3