From: Tejun Heo <tj@kernel.org>

Date: Fri, 23 Sep 2022 07:23:06 -1000

Subject: cgroup: Make cgroup_get_from_id() prettier

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Git-commit: 7e1eb5437d3c3fdb61d45378579aab383cafc694

Patch-mainline: v6.1-rc1

References: bsc#1205650

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 <tj@kernel.org>

Cc: Ming Lei <ming.lei@redhat.com>

Cc: Michal Koutný <mkoutny@suse.com>

Acked-by: Michal Koutný <mkoutny@suse.com>

---

 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);