cgroup: implement cgroup_get_from_path() and expose cgroup_put() (16af4396) · Commits · 戴 / test

include/linux/cgroup.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -81,6 +81,8 @@ struct cgroup_subsys_state cgroup_get_e_css(struct cgroup cgroup,
		struct cgroup_subsys_state css_tryget_online_from_dir(struct dentry dentry,
		struct cgroup_subsys *ss);

		struct cgroup cgroup_get_from_path(const char path);

		int cgroup_attach_task_all(struct task_struct from, struct task_struct );
		int cgroup_transfer_tasks(struct cgroup to, struct cgroup from);

		@@ -351,6 +353,11 @@ static inline void css_put_many(struct cgroup_subsys_state *css, unsigned int n)
		percpu_ref_put_many(&css->refcnt, n);
		}

		static inline void cgroup_put(struct cgroup *cgrp)
		{
		css_put(&cgrp->self);
		}

		/**
		* task_css_set_check - obtain a task's css_set with extra access conditions
		* @task: the task to obtain css_set for

+34 −5

Original line number	Diff line number	Diff line
		@@ -434,11 +434,6 @@ static bool cgroup_tryget(struct cgroup *cgrp)
		return css_tryget(&cgrp->self);
		}

		static void cgroup_put(struct cgroup *cgrp)
		{
		css_put(&cgrp->self);
		}

		struct cgroup_subsys_state of_css(struct kernfs_open_file of)
		{
		struct cgroup *cgrp = of->kn->parent->priv;
		@@ -5753,6 +5748,40 @@ struct cgroup_subsys_state css_from_id(int id, struct cgroup_subsys ss)
		return id > 0 ? idr_find(&ss->css_idr, id) : NULL;
		}

		/**
		* 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);

		#ifdef CONFIG_CGROUP_DEBUG
		static struct cgroup_subsys_state *
		debug_css_alloc(struct cgroup_subsys_state *parent_css)