Commit d0a3a4b2 authored by Alexei Starovoitov's avatar Alexei Starovoitov
Browse files

Merge branch 'cgroup-auto-detach' 



Roman Gushchin says:

====================
This patchset implements a cgroup bpf auto-detachment functionality:
bpf programs are detached as soon as possible after removal of the
cgroup, without waiting for the release of all associated resources.

Patches 2 and 3 are required to implement a corresponding kselftest
in patch 4.

v5:
  1) rebase

v4:
  1) release cgroup bpf data using a workqueue
  2) add test_cgroup_attach to .gitignore

v3:
  1) some minor changes and typo fixes

v2:
  1) removed a bogus check in patch 4
  2) moved buf[len] = 0 in patch 2
====================

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parents 37b54aed d5506591

include/linux/bpf-cgroup.h

+9 −2
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <linux/errno.h>

#include <linux/jump_label.h>

#include <linux/percpu.h>

#include <linux/percpu-refcount.h>

#include <linux/rbtree.h>

#include <uapi/linux/bpf.h>
@@ -72,10 +73,16 @@ struct cgroup_bpf { 


	/* temp storage for effective prog array used by prog_attach/detach */

	struct bpf_prog_array __rcu *inactive;



	/* reference counter used to detach bpf programs after cgroup removal */

	struct percpu_ref refcnt;



	/* cgroup_bpf is released using a work queue */

	struct work_struct release_work;

};



void cgroup_bpf_put(struct cgroup *cgrp);

int cgroup_bpf_inherit(struct cgroup *cgrp);

void cgroup_bpf_offline(struct cgroup *cgrp);



int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,

			enum bpf_attach_type type, u32 flags);
@@ -283,8 +290,8 @@ int cgroup_bpf_prog_query(const union bpf_attr *attr, 


struct bpf_prog;

struct cgroup_bpf {};

static inline void cgroup_bpf_put(struct cgroup *cgrp) {}

static inline int cgroup_bpf_inherit(struct cgroup *cgrp) { return 0; }

static inline void cgroup_bpf_offline(struct cgroup *cgrp) {}



static inline int cgroup_bpf_prog_attach(const union bpf_attr *attr,

					 enum bpf_prog_type ptype,

include/linux/cgroup.h

+18 −0
Original line number Diff line number Diff line
@@ -924,4 +924,22 @@ static inline bool cgroup_task_frozen(struct task_struct *task) 


#endif /* !CONFIG_CGROUPS */



#ifdef CONFIG_CGROUP_BPF

static inline void cgroup_bpf_get(struct cgroup *cgrp)

{

	percpu_ref_get(&cgrp->bpf.refcnt);

}



static inline void cgroup_bpf_put(struct cgroup *cgrp)

{

	percpu_ref_put(&cgrp->bpf.refcnt);

}



#else /* CONFIG_CGROUP_BPF */



static inline void cgroup_bpf_get(struct cgroup *cgrp) {}

static inline void cgroup_bpf_put(struct cgroup *cgrp) {}



#endif /* CONFIG_CGROUP_BPF */



#endif /* _LINUX_CGROUP_H */

kernel/bpf/cgroup.c

+37 −4
Original line number Diff line number Diff line
@@ -22,12 +22,21 @@ 
DEFINE_STATIC_KEY_FALSE(cgroup_bpf_enabled_key);

EXPORT_SYMBOL(cgroup_bpf_enabled_key);



void cgroup_bpf_offline(struct cgroup *cgrp)

{

	cgroup_get(cgrp);

	percpu_ref_kill(&cgrp->bpf.refcnt);

}



/**

 * cgroup_bpf_put() - put references of all bpf programs

 * @cgrp: the cgroup to modify

 * cgroup_bpf_release() - put references of all bpf programs and

 *                        release all cgroup bpf data

 * @work: work structure embedded into the cgroup to modify

 */

void cgroup_bpf_put(struct cgroup *cgrp)

static void cgroup_bpf_release(struct work_struct *work)

{

	struct cgroup *cgrp = container_of(work, struct cgroup,

					   bpf.release_work);

	enum bpf_cgroup_storage_type stype;

	unsigned int type;
@@ -47,6 +56,22 @@ void cgroup_bpf_put(struct cgroup *cgrp) 
		}

		bpf_prog_array_free(cgrp->bpf.effective[type]);

	}



	percpu_ref_exit(&cgrp->bpf.refcnt);

	cgroup_put(cgrp);

}



/**

 * cgroup_bpf_release_fn() - callback used to schedule releasing

 *                           of bpf cgroup data

 * @ref: percpu ref counter structure

 */

static void cgroup_bpf_release_fn(struct percpu_ref *ref)

{

	struct cgroup *cgrp = container_of(ref, struct cgroup, bpf.refcnt);



	INIT_WORK(&cgrp->bpf.release_work, cgroup_bpf_release);

	queue_work(system_wq, &cgrp->bpf.release_work);

}



/* count number of elements in the list.
@@ -167,7 +192,12 @@ int cgroup_bpf_inherit(struct cgroup *cgrp) 
 */

#define	NR ARRAY_SIZE(cgrp->bpf.effective)

	struct bpf_prog_array __rcu *arrays[NR] = {};

	int i;

	int ret, i;



	ret = percpu_ref_init(&cgrp->bpf.refcnt, cgroup_bpf_release_fn, 0,

			      GFP_KERNEL);

	if (ret)

		return ret;



	for (i = 0; i < NR; i++)

		INIT_LIST_HEAD(&cgrp->bpf.progs[i]);
@@ -183,6 +213,9 @@ int cgroup_bpf_inherit(struct cgroup *cgrp) 
cleanup:

	for (i = 0; i < NR; i++)

		bpf_prog_array_free(arrays[i]);



	percpu_ref_exit(&cgrp->bpf.refcnt);



	return -ENOMEM;

}

kernel/cgroup/cgroup.c

+8 −3
Original line number Diff line number Diff line
@@ -4955,8 +4955,6 @@ static void css_release_work_fn(struct work_struct *work) 
		if (cgrp->kn)

			RCU_INIT_POINTER(*(void __rcu __force **)&cgrp->kn->priv,

					 NULL);



		cgroup_bpf_put(cgrp);

	}



	mutex_unlock(&cgroup_mutex);
@@ -5482,6 +5480,8 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) 


	cgroup1_check_for_release(parent);



	cgroup_bpf_offline(cgrp);



	/* put the base reference */

	percpu_ref_kill(&cgrp->self.refcnt);
@@ -6221,6 +6221,7 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd) 
		 * Don't use cgroup_get_live().

		 */

		cgroup_get(sock_cgroup_ptr(skcd));

		cgroup_bpf_get(sock_cgroup_ptr(skcd));

		return;

	}
@@ -6232,6 +6233,7 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd) 
		cset = task_css_set(current);

		if (likely(cgroup_tryget(cset->dfl_cgrp))) {

			skcd->val = (unsigned long)cset->dfl_cgrp;

			cgroup_bpf_get(cset->dfl_cgrp);

			break;

		}

		cpu_relax();
@@ -6242,7 +6244,10 @@ void cgroup_sk_alloc(struct sock_cgroup_data *skcd) 


void cgroup_sk_free(struct sock_cgroup_data *skcd)

{

	cgroup_put(sock_cgroup_ptr(skcd));

	struct cgroup *cgrp = sock_cgroup_ptr(skcd);



	cgroup_bpf_put(cgrp);

	cgroup_put(cgrp);

}



#endif	/* CONFIG_SOCK_CGROUP_DATA */

samples/bpf/Makefile

+0 −2
Original line number Diff line number Diff line
@@ -26,7 +26,6 @@ hostprogs-y += map_perf_test 
hostprogs-y += test_overhead

hostprogs-y += test_cgrp2_array_pin

hostprogs-y += test_cgrp2_attach

hostprogs-y += test_cgrp2_attach2

hostprogs-y += test_cgrp2_sock

hostprogs-y += test_cgrp2_sock2

hostprogs-y += xdp1
@@ -81,7 +80,6 @@ map_perf_test-objs := bpf_load.o map_perf_test_user.o 
test_overhead-objs := bpf_load.o test_overhead_user.o

test_cgrp2_array_pin-objs := test_cgrp2_array_pin.o

test_cgrp2_attach-objs := test_cgrp2_attach.o

test_cgrp2_attach2-objs := test_cgrp2_attach2.o $(CGROUP_HELPERS)

test_cgrp2_sock-objs := test_cgrp2_sock.o

test_cgrp2_sock2-objs := bpf_load.o test_cgrp2_sock2.o

xdp1-objs := xdp1_user.o

CRA Git | Maintained and supported by SUSTech CRA and CCSE