[PATCH bpf-next 1/9] bpf: extend cgroup bpf core to allow multiple cgroup storage types

From: Roman Gushchin
Date: Fri Sep 21 2018 - 13:15:18 EST

In order to introduce per-cpu cgroup storage, let's generalize
bpf cgroup core to support multiple cgroup storage types.
Potentially, per-node cgroup storage can be added later.

This commit is mostly a formal change that replaces
cgroup_storage pointer with a array of cgroup_storage pointers.
It doesn't actually introduce a new storage type,
it will be done later.

Each bpf program is now able to have one cgroup storage of each type.

Signed-off-by: Roman Gushchin <guro@xxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
---
include/linux/bpf-cgroup.h | 38 ++++++++++++++------
include/linux/bpf.h | 11 ++++--
kernel/bpf/cgroup.c | 74 ++++++++++++++++++++++++++------------
kernel/bpf/helpers.c | 15 ++++----
kernel/bpf/local_storage.c | 18 ++++++----
kernel/bpf/syscall.c | 9 +++--
kernel/bpf/verifier.c | 8 +++--
net/bpf/test_run.c | 20 +++++++----
8 files changed, 136 insertions(+), 57 deletions(-)

diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h
index f91b0f8ff3a9..e9871b012dac 100644
--- a/include/linux/bpf-cgroup.h
+++ b/include/linux/bpf-cgroup.h
@@ -2,6 +2,7 @@
#ifndef _BPF_CGROUP_H
#define _BPF_CGROUP_H

+#include <linux/bpf.h>
#include <linux/errno.h>
#include <linux/jump_label.h>
#include <linux/percpu.h>
@@ -22,7 +23,10 @@ struct bpf_cgroup_storage;
extern struct static_key_false cgroup_bpf_enabled_key;
#define cgroup_bpf_enabled static_branch_unlikely(&cgroup_bpf_enabled_key)

-DECLARE_PER_CPU(void*, bpf_cgroup_storage);
+DECLARE_PER_CPU(void*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);
+
+#define for_each_cgroup_storage_type(stype) \
+ for (stype = 0; stype < MAX_BPF_CGROUP_STORAGE_TYPE; stype++)

struct bpf_cgroup_storage_map;

@@ -43,7 +47,7 @@ struct bpf_cgroup_storage {
struct bpf_prog_list {
struct list_head node;
struct bpf_prog *prog;
- struct bpf_cgroup_storage *storage;
+ struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE];
};

struct bpf_prog_array;
@@ -101,18 +105,29 @@ int __cgroup_bpf_run_filter_sock_ops(struct sock *sk,
int __cgroup_bpf_check_dev_permission(short dev_type, u32 major, u32 minor,
short access, enum bpf_attach_type type);

-static inline void bpf_cgroup_storage_set(struct bpf_cgroup_storage *storage)
+static inline enum bpf_cgroup_storage_type cgroup_storage_type(
+ struct bpf_map *map)
{
+ return BPF_CGROUP_STORAGE_SHARED;
+}
+
+static inline void bpf_cgroup_storage_set(struct bpf_cgroup_storage
+ *storage[MAX_BPF_CGROUP_STORAGE_TYPE])
+{
+ enum bpf_cgroup_storage_type stype;
struct bpf_storage_buffer *buf;

- if (!storage)
- return;
+ for_each_cgroup_storage_type(stype) {
+ if (!storage[stype])
+ continue;

- buf = READ_ONCE(storage->buf);
- this_cpu_write(bpf_cgroup_storage, &buf->data[0]);
+ buf = READ_ONCE(storage[stype]->buf);
+ this_cpu_write(bpf_cgroup_storage[stype], &buf->data[0]);
+ }
}

-struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog);
+struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog,
+ enum bpf_cgroup_storage_type stype);
void bpf_cgroup_storage_free(struct bpf_cgroup_storage *storage);
void bpf_cgroup_storage_link(struct bpf_cgroup_storage *storage,
struct cgroup *cgroup,
@@ -265,13 +280,14 @@ static inline int cgroup_bpf_prog_query(const union bpf_attr *attr,
return -EINVAL;
}

-static inline void bpf_cgroup_storage_set(struct bpf_cgroup_storage *storage) {}
+static inline void bpf_cgroup_storage_set(
+ struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE]) {}
static inline int bpf_cgroup_storage_assign(struct bpf_prog *prog,
struct bpf_map *map) { return 0; }
static inline void bpf_cgroup_storage_release(struct bpf_prog *prog,
struct bpf_map *map) {}
static inline struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(
- struct bpf_prog *prog) { return 0; }
+ struct bpf_prog *prog, enum bpf_cgroup_storage_type stype) { return 0; }
static inline void bpf_cgroup_storage_free(
struct bpf_cgroup_storage *storage) {}

@@ -293,6 +309,8 @@ static inline void bpf_cgroup_storage_free(
#define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops) ({ 0; })
#define BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(type,major,minor,access) ({ 0; })

+#define for_each_cgroup_storage_type(stype) for (; false; )
+
#endif /* CONFIG_CGROUP_BPF */

#endif /* _BPF_CGROUP_H */
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 988a00797bcd..b457fbe7b70b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -272,6 +272,13 @@ struct bpf_prog_offload {
u32 jited_len;
};

+enum bpf_cgroup_storage_type {
+ BPF_CGROUP_STORAGE_SHARED,
+ __BPF_CGROUP_STORAGE_MAX
+};
+
+#define MAX_BPF_CGROUP_STORAGE_TYPE __BPF_CGROUP_STORAGE_MAX
+
struct bpf_prog_aux {
atomic_t refcnt;
u32 used_map_cnt;
@@ -289,7 +296,7 @@ struct bpf_prog_aux {
struct bpf_prog *prog;
struct user_struct *user;
u64 load_time; /* ns since boottime */
- struct bpf_map *cgroup_storage;
+ struct bpf_map *cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE];
char name[BPF_OBJ_NAME_LEN];
#ifdef CONFIG_SECURITY
void *security;
@@ -358,7 +365,7 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
*/
struct bpf_prog_array_item {
struct bpf_prog *prog;
- struct bpf_cgroup_storage *cgroup_storage;
+ struct bpf_cgroup_storage *cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE];
};

struct bpf_prog_array {
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 6a7d931bbc55..065c3d9ff8eb 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -25,6 +25,7 @@ EXPORT_SYMBOL(cgroup_bpf_enabled_key);
*/
void cgroup_bpf_put(struct cgroup *cgrp)
{
+ enum bpf_cgroup_storage_type stype;
unsigned int type;

for (type = 0; type < ARRAY_SIZE(cgrp->bpf.progs); type++) {
@@ -34,8 +35,10 @@ void cgroup_bpf_put(struct cgroup *cgrp)
list_for_each_entry_safe(pl, tmp, progs, node) {
list_del(&pl->node);
bpf_prog_put(pl->prog);
- bpf_cgroup_storage_unlink(pl->storage);
- bpf_cgroup_storage_free(pl->storage);
+ for_each_cgroup_storage_type(stype) {
+ bpf_cgroup_storage_unlink(pl->storage[stype]);
+ bpf_cgroup_storage_free(pl->storage[stype]);
+ }
kfree(pl);
static_branch_dec(&cgroup_bpf_enabled_key);
}
@@ -97,6 +100,7 @@ static int compute_effective_progs(struct cgroup *cgrp,
enum bpf_attach_type type,
struct bpf_prog_array __rcu **array)
{
+ enum bpf_cgroup_storage_type stype;
struct bpf_prog_array *progs;
struct bpf_prog_list *pl;
struct cgroup *p = cgrp;
@@ -125,7 +129,9 @@ static int compute_effective_progs(struct cgroup *cgrp,
continue;

progs->items[cnt].prog = pl->prog;
- progs->items[cnt].cgroup_storage = pl->storage;
+ for_each_cgroup_storage_type(stype)
+ progs->items[cnt].cgroup_storage[stype] =
+ pl->storage[stype];
cnt++;
}
} while ((p = cgroup_parent(p)));
@@ -232,7 +238,9 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
{
struct list_head *progs = &cgrp->bpf.progs[type];
struct bpf_prog *old_prog = NULL;
- struct bpf_cgroup_storage *storage, *old_storage = NULL;
+ struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE],
+ *old_storage[MAX_BPF_CGROUP_STORAGE_TYPE] = {NULL};
+ enum bpf_cgroup_storage_type stype;
struct bpf_prog_list *pl;
bool pl_was_allocated;
int err;
@@ -254,34 +262,44 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
if (prog_list_length(progs) >= BPF_CGROUP_MAX_PROGS)
return -E2BIG;

- storage = bpf_cgroup_storage_alloc(prog);
- if (IS_ERR(storage))
- return -ENOMEM;
+ for_each_cgroup_storage_type(stype) {
+ storage[stype] = bpf_cgroup_storage_alloc(prog, stype);
+ if (IS_ERR(storage[stype])) {
+ storage[stype] = NULL;
+ for_each_cgroup_storage_type(stype)
+ bpf_cgroup_storage_free(storage[stype]);
+ return -ENOMEM;
+ }
+ }

if (flags & BPF_F_ALLOW_MULTI) {
list_for_each_entry(pl, progs, node) {
if (pl->prog == prog) {
/* disallow attaching the same prog twice */
- bpf_cgroup_storage_free(storage);
+ for_each_cgroup_storage_type(stype)
+ bpf_cgroup_storage_free(storage[stype]);
return -EINVAL;
}
}

pl = kmalloc(sizeof(*pl), GFP_KERNEL);
if (!pl) {
- bpf_cgroup_storage_free(storage);
+ for_each_cgroup_storage_type(stype)
+ bpf_cgroup_storage_free(storage[stype]);
return -ENOMEM;
}

pl_was_allocated = true;
pl->prog = prog;
- pl->storage = storage;
+ for_each_cgroup_storage_type(stype)
+ pl->storage[stype] = storage[stype];
list_add_tail(&pl->node, progs);
} else {
if (list_empty(progs)) {
pl = kmalloc(sizeof(*pl), GFP_KERNEL);
if (!pl) {
- bpf_cgroup_storage_free(storage);
+ for_each_cgroup_storage_type(stype)
+ bpf_cgroup_storage_free(storage[stype]);
return -ENOMEM;
}
pl_was_allocated = true;
@@ -289,12 +307,15 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
} else {
pl = list_first_entry(progs, typeof(*pl), node);
old_prog = pl->prog;
- old_storage = pl->storage;
- bpf_cgroup_storage_unlink(old_storage);
+ for_each_cgroup_storage_type(stype) {
+ old_storage[stype] = pl->storage[stype];
+ bpf_cgroup_storage_unlink(old_storage[stype]);
+ }
pl_was_allocated = false;
}
pl->prog = prog;
- pl->storage = storage;
+ for_each_cgroup_storage_type(stype)
+ pl->storage[stype] = storage[stype];
}

cgrp->bpf.flags[type] = flags;
@@ -304,21 +325,27 @@ int __cgroup_bpf_attach(struct cgroup *cgrp, struct bpf_prog *prog,
goto cleanup;

static_branch_inc(&cgroup_bpf_enabled_key);
- if (old_storage)
- bpf_cgroup_storage_free(old_storage);
+ for_each_cgroup_storage_type(stype) {
+ if (!old_storage[stype])
+ continue;
+ bpf_cgroup_storage_free(old_storage[stype]);
+ }
if (old_prog) {
bpf_prog_put(old_prog);
static_branch_dec(&cgroup_bpf_enabled_key);
}
- bpf_cgroup_storage_link(storage, cgrp, type);
+ for_each_cgroup_storage_type(stype)
+ bpf_cgroup_storage_link(storage[stype], cgrp, type);
return 0;

cleanup:
/* and cleanup the prog list */
pl->prog = old_prog;
- bpf_cgroup_storage_free(pl->storage);
- pl->storage = old_storage;
- bpf_cgroup_storage_link(old_storage, cgrp, type);
+ for_each_cgroup_storage_type(stype) {
+ bpf_cgroup_storage_free(pl->storage[stype]);
+ pl->storage[stype] = old_storage[stype];
+ bpf_cgroup_storage_link(old_storage[stype], cgrp, type);
+ }
if (pl_was_allocated) {
list_del(&pl->node);
kfree(pl);
@@ -339,6 +366,7 @@ int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
enum bpf_attach_type type, u32 unused_flags)
{
struct list_head *progs = &cgrp->bpf.progs[type];
+ enum bpf_cgroup_storage_type stype;
u32 flags = cgrp->bpf.flags[type];
struct bpf_prog *old_prog = NULL;
struct bpf_prog_list *pl;
@@ -385,8 +413,10 @@ int __cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,

/* now can actually delete it from this cgroup list */
list_del(&pl->node);
- bpf_cgroup_storage_unlink(pl->storage);
- bpf_cgroup_storage_free(pl->storage);
+ for_each_cgroup_storage_type(stype) {
+ bpf_cgroup_storage_unlink(pl->storage[stype]);
+ bpf_cgroup_storage_free(pl->storage[stype]);
+ }
kfree(pl);
if (list_empty(progs))
/* last program was detached, reset flags to zero */
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 1991466b8327..9070b2ace6aa 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -194,16 +194,18 @@ const struct bpf_func_proto bpf_get_current_cgroup_id_proto = {
.ret_type = RET_INTEGER,
};

-DECLARE_PER_CPU(void*, bpf_cgroup_storage);
+#ifdef CONFIG_CGROUP_BPF
+DECLARE_PER_CPU(void*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);

BPF_CALL_2(bpf_get_local_storage, struct bpf_map *, map, u64, flags)
{
- /* map and flags arguments are not used now,
- * but provide an ability to extend the API
- * for other types of local storages.
- * verifier checks that their values are correct.
+ /* flags argument is not used now,
+ * but provides an ability to extend the API.
+ * verifier checks that its value is correct.
*/
- return (unsigned long) this_cpu_read(bpf_cgroup_storage);
+ enum bpf_cgroup_storage_type stype = cgroup_storage_type(map);
+
+ return (unsigned long) this_cpu_read(bpf_cgroup_storage[stype]);
}

const struct bpf_func_proto bpf_get_local_storage_proto = {
@@ -214,3 +216,4 @@ const struct bpf_func_proto bpf_get_local_storage_proto = {
.arg2_type = ARG_ANYTHING,
};
#endif
+#endif
diff --git a/kernel/bpf/local_storage.c b/kernel/bpf/local_storage.c
index 22ad967d1e5f..0bd9f19fc557 100644
--- a/kernel/bpf/local_storage.c
+++ b/kernel/bpf/local_storage.c
@@ -7,7 +7,7 @@
#include <linux/rbtree.h>
#include <linux/slab.h>

-DEFINE_PER_CPU(void*, bpf_cgroup_storage);
+DEFINE_PER_CPU(void*, bpf_cgroup_storage[MAX_BPF_CGROUP_STORAGE_TYPE]);

#ifdef CONFIG_CGROUP_BPF

@@ -251,6 +251,7 @@ const struct bpf_map_ops cgroup_storage_map_ops = {

int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map)
{
+ enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);
struct bpf_cgroup_storage_map *map = map_to_storage(_map);
int ret = -EBUSY;

@@ -258,11 +259,12 @@ int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map)

if (map->prog && map->prog != prog)
goto unlock;
- if (prog->aux->cgroup_storage && prog->aux->cgroup_storage != _map)
+ if (prog->aux->cgroup_storage[stype] &&
+ prog->aux->cgroup_storage[stype] != _map)
goto unlock;

map->prog = prog;
- prog->aux->cgroup_storage = _map;
+ prog->aux->cgroup_storage[stype] = _map;
ret = 0;
unlock:
spin_unlock_bh(&map->lock);
@@ -272,24 +274,26 @@ int bpf_cgroup_storage_assign(struct bpf_prog *prog, struct bpf_map *_map)

void bpf_cgroup_storage_release(struct bpf_prog *prog, struct bpf_map *_map)
{
+ enum bpf_cgroup_storage_type stype = cgroup_storage_type(_map);
struct bpf_cgroup_storage_map *map = map_to_storage(_map);

spin_lock_bh(&map->lock);
if (map->prog == prog) {
- WARN_ON(prog->aux->cgroup_storage != _map);
+ WARN_ON(prog->aux->cgroup_storage[stype] != _map);
map->prog = NULL;
- prog->aux->cgroup_storage = NULL;
+ prog->aux->cgroup_storage[stype] = NULL;
}
spin_unlock_bh(&map->lock);
}

-struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog)
+struct bpf_cgroup_storage *bpf_cgroup_storage_alloc(struct bpf_prog *prog,
+ enum bpf_cgroup_storage_type stype)
{
struct bpf_cgroup_storage *storage;
struct bpf_map *map;
u32 pages;

- map = prog->aux->cgroup_storage;
+ map = prog->aux->cgroup_storage[stype];
if (!map)
return NULL;

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index b3c2d09bcf7a..8c91d2b41b1e 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -988,10 +988,15 @@ static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
/* drop refcnt on maps used by eBPF program and free auxilary data */
static void free_used_maps(struct bpf_prog_aux *aux)
{
+ enum bpf_cgroup_storage_type stype;
int i;

- if (aux->cgroup_storage)
- bpf_cgroup_storage_release(aux->prog, aux->cgroup_storage);
+ for_each_cgroup_storage_type(stype) {
+ if (!aux->cgroup_storage[stype])
+ continue;
+ bpf_cgroup_storage_release(aux->prog,
+ aux->cgroup_storage[stype]);
+ }

for (i = 0; i < aux->used_map_cnt; i++)
bpf_map_put(aux->used_maps[i]);
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 8ccbff4fff93..e75f36de91d6 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5171,11 +5171,15 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
/* drop refcnt of maps used by the rejected program */
static void release_maps(struct bpf_verifier_env *env)
{
+ enum bpf_cgroup_storage_type stype;
int i;

- if (env->prog->aux->cgroup_storage)
+ for_each_cgroup_storage_type(stype) {
+ if (!env->prog->aux->cgroup_storage[stype])
+ continue;
bpf_cgroup_storage_release(env->prog,
- env->prog->aux->cgroup_storage);
+ env->prog->aux->cgroup_storage[stype]);
+ }

for (i = 0; i < env->used_map_cnt; i++)
bpf_map_put(env->used_maps[i]);
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index f4078830ea50..0c423b8cd75c 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -12,7 +12,7 @@
#include <linux/sched/signal.h>

static __always_inline u32 bpf_test_run_one(struct bpf_prog *prog, void *ctx,
- struct bpf_cgroup_storage *storage)
+ struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE])
{
u32 ret;

@@ -28,13 +28,20 @@ static __always_inline u32 bpf_test_run_one(struct bpf_prog *prog, void *ctx,

static u32 bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, u32 *time)
{
- struct bpf_cgroup_storage *storage = NULL;
+ struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = { 0 };
+ enum bpf_cgroup_storage_type stype;
u64 time_start, time_spent = 0;
u32 ret = 0, i;

- storage = bpf_cgroup_storage_alloc(prog);
- if (IS_ERR(storage))
- return PTR_ERR(storage);
+ for_each_cgroup_storage_type(stype) {
+ storage[stype] = bpf_cgroup_storage_alloc(prog, stype);
+ if (IS_ERR(storage[stype])) {
+ storage[stype] = NULL;
+ for_each_cgroup_storage_type(stype)
+ bpf_cgroup_storage_free(storage[stype]);
+ return -ENOMEM;
+ }
+ }

if (!repeat)
repeat = 1;
@@ -53,7 +60,8 @@ static u32 bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat, u32 *time)
do_div(time_spent, repeat);
*time = time_spent > U32_MAX ? U32_MAX : (u32)time_spent;

- bpf_cgroup_storage_free(storage);
+ for_each_cgroup_storage_type(stype)
+ bpf_cgroup_storage_free(storage[stype]);

return ret;
}
--
2.17.1