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Commit aed704b7 authored by Sargun Dhillon's avatar Sargun Dhillon Committed by David S. Miller
Browse files

cgroup: Add task_under_cgroup_hierarchy cgroup inline function to headers 



This commit adds an inline function to cgroup.h to check whether a given
task is under a given cgroup hierarchy. This is to avoid having to put
ifdefs in .c files to gate access to cgroups. When cgroups are disabled
this always returns true.

Signed-off-by: default avatarSargun Dhillon <sargun@sargun.me>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f9f9ab17

include/linux/cgroup.h

+23 −0
Original line number Diff line number Diff line
@@ -497,6 +497,23 @@ static inline bool cgroup_is_descendant(struct cgroup *cgrp, 
	return cgrp->ancestor_ids[ancestor->level] == ancestor->id;

}



/**

 * task_under_cgroup_hierarchy - test task's membership of cgroup ancestry

 * @task: the task to be tested

 * @ancestor: possible ancestor of @task's cgroup

 *

 * Tests whether @task's default cgroup hierarchy is a descendant of @ancestor.

 * It follows all the same rules as cgroup_is_descendant, and only applies

 * to the default hierarchy.

 */

static inline bool task_under_cgroup_hierarchy(struct task_struct *task,

					       struct cgroup *ancestor)

{

	struct css_set *cset = task_css_set(task);



	return cgroup_is_descendant(cset->dfl_cgrp, ancestor);

}



/* no synchronization, the result can only be used as a hint */

static inline bool cgroup_is_populated(struct cgroup *cgrp)

{
@@ -557,6 +574,7 @@ static inline void pr_cont_cgroup_path(struct cgroup *cgrp) 
#else /* !CONFIG_CGROUPS */



struct cgroup_subsys_state;

struct cgroup;



static inline void css_put(struct cgroup_subsys_state *css) {}

static inline int cgroup_attach_task_all(struct task_struct *from,
@@ -574,6 +592,11 @@ static inline void cgroup_free(struct task_struct *p) {} 
static inline int cgroup_init_early(void) { return 0; }

static inline int cgroup_init(void) { return 0; }



static inline bool task_under_cgroup_hierarchy(struct task_struct *task,

					       struct cgroup *ancestor)

{

	return true;

}

#endif /* !CONFIG_CGROUPS */



/*