+/**
+ * cgroup_get_from_path - lookup and get a cgroup from its default hierarchy path
+ * @path: path on the default hierarchy
+ *
+ * Find the cgroup at @path on the default hierarchy, increment its
+ * reference count and return it. Returns pointer to the found cgroup on
+ * success, ERR_PTR(-ENOENT) if @path doens't exist and ERR_PTR(-ENOTDIR)
+ * if @path points to a non-directory.
+ */
+struct cgroup *cgroup_get_from_path(const char *path)
+{
+ struct kernfs_node *kn;
+ struct cgroup *cgrp;
+
+ mutex_lock(&cgroup_mutex);
+
+ kn = kernfs_walk_and_get(cgrp_dfl_root.cgrp.kn, path);
+ if (kn) {
+ if (kernfs_type(kn) == KERNFS_DIR) {
+ cgrp = kn->priv;
+ cgroup_get(cgrp);
+ } else {
+ cgrp = ERR_PTR(-ENOTDIR);
+ }
+ kernfs_put(kn);
+ } else {
+ cgrp = ERR_PTR(-ENOENT);
+ }
+
+ mutex_unlock(&cgroup_mutex);
+ return cgrp;
+}
+EXPORT_SYMBOL_GPL(cgroup_get_from_path);
+
+/*
+ * sock->sk_cgrp_data handling. For more info, see sock_cgroup_data
+ * definition in cgroup-defs.h.
+ */
+#ifdef CONFIG_SOCK_CGROUP_DATA
+
+#if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID)
+
+DEFINE_SPINLOCK(cgroup_sk_update_lock);
+static bool cgroup_sk_alloc_disabled __read_mostly;
+
+void cgroup_sk_alloc_disable(void)
+{
+ if (cgroup_sk_alloc_disabled)
+ return;
+ pr_info("cgroup: disabling cgroup2 socket matching due to net_prio or net_cls activation\n");
+ cgroup_sk_alloc_disabled = true;
+}
+
+#else
+
+#define cgroup_sk_alloc_disabled false
+
+#endif
+
+void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
+{
+ if (cgroup_sk_alloc_disabled)
+ return;
+
+ rcu_read_lock();
+
+ while (true) {
+ struct css_set *cset;
+
+ cset = task_css_set(current);
+ if (likely(cgroup_tryget(cset->dfl_cgrp))) {
+ skcd->val = (unsigned long)cset->dfl_cgrp;
+ break;
+ }
+ cpu_relax();
+ }
+
+ rcu_read_unlock();
+}
+
+void cgroup_sk_free(struct sock_cgroup_data *skcd)
+{
+ cgroup_put(sock_cgroup_ptr(skcd));
+}
+
+#endif /* CONFIG_SOCK_CGROUP_DATA */
+