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Message-Id: <20240118014930.1992551-12-thinker.li@gmail.com>
Date: Wed, 17 Jan 2024 17:49:27 -0800
From: thinker.li@...il.com
To: bpf@...r.kernel.org,
ast@...nel.org,
martin.lau@...ux.dev,
song@...nel.org,
kernel-team@...a.com,
andrii@...nel.org,
drosen@...gle.com
Cc: sinquersw@...il.com,
kuifeng@...a.com,
Kui-Feng Lee <thinker.li@...il.com>,
netdev@...r.kernel.org
Subject: [PATCH bpf-next v16 11/14] bpf, net: switch to dynamic registration
From: Kui-Feng Lee <thinker.li@...il.com>
Replace the static list of struct_ops types with per-btf struct_ops_tab to
enable dynamic registration.
Both bpf_dummy_ops and bpf_tcp_ca now utilize the registration function
instead of being listed in bpf_struct_ops_types.h.
Cc: netdev@...r.kernel.org
Signed-off-by: Kui-Feng Lee <thinker.li@...il.com>
---
include/linux/bpf.h | 37 ++++++++---
include/linux/btf.h | 12 ++++
kernel/bpf/bpf_struct_ops.c | 100 ++++--------------------------
kernel/bpf/bpf_struct_ops_types.h | 12 ----
kernel/bpf/btf.c | 84 +++++++++++++++++++++++--
net/bpf/bpf_dummy_struct_ops.c | 11 +++-
net/ipv4/bpf_tcp_ca.c | 12 +++-
7 files changed, 150 insertions(+), 118 deletions(-)
delete mode 100644 kernel/bpf/bpf_struct_ops_types.h
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 1cfbb89944c5..a2522fcfe57c 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1700,10 +1700,22 @@ struct bpf_struct_ops_common_value {
enum bpf_struct_ops_state state;
};
+/* This macro helps developer to register a struct_ops type and generate
+ * type information correctly. Developers should use this macro to register
+ * a struct_ops type instead of calling register_bpf_struct_ops() directly.
+ */
+#define REGISTER_BPF_STRUCT_OPS(st_ops, type) \
+ ({ \
+ struct bpf_struct_ops_##type { \
+ struct bpf_struct_ops_common_value common; \
+ struct type data ____cacheline_aligned_in_smp; \
+ }; \
+ BTF_TYPE_EMIT(struct bpf_struct_ops_##type); \
+ register_bpf_struct_ops(st_ops); \
+ })
+
#if defined(CONFIG_BPF_JIT) && defined(CONFIG_BPF_SYSCALL)
#define BPF_MODULE_OWNER ((void *)((0xeB9FUL << 2) + POISON_POINTER_DELTA))
-const struct bpf_struct_ops_desc *bpf_struct_ops_find(struct btf *btf, u32 type_id);
-void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log);
bool bpf_struct_ops_get(const void *kdata);
void bpf_struct_ops_put(const void *kdata);
int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key,
@@ -1745,16 +1757,11 @@ struct bpf_dummy_ops {
int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr,
union bpf_attr __user *uattr);
#endif
+int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
+ struct btf *btf,
+ struct bpf_verifier_log *log);
void bpf_map_struct_ops_info_fill(struct bpf_map_info *info, struct bpf_map *map);
#else
-static inline const struct bpf_struct_ops_desc *bpf_struct_ops_find(struct btf *btf, u32 type_id)
-{
- return NULL;
-}
-static inline void bpf_struct_ops_init(struct btf *btf,
- struct bpf_verifier_log *log)
-{
-}
static inline bool bpf_try_module_get(const void *data, struct module *owner)
{
return try_module_get(owner);
@@ -1769,6 +1776,10 @@ static inline int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map,
{
return -EINVAL;
}
+static inline int bpf_struct_ops_link_create(union bpf_attr *attr)
+{
+ return -EOPNOTSUPP;
+}
#endif
#if defined(CONFIG_CGROUP_BPF) && defined(CONFIG_BPF_LSM)
@@ -1784,6 +1795,12 @@ static inline int bpf_trampoline_link_cgroup_shim(struct bpf_prog *prog,
static inline void bpf_trampoline_unlink_cgroup_shim(struct bpf_prog *prog)
{
}
+static inline int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
+ struct btf *btf,
+ struct bpf_verifier_log *log) {
+ return -EOPNOTSUPP;
+}
+
#endif
struct bpf_array {
diff --git a/include/linux/btf.h b/include/linux/btf.h
index a68604904f4e..bc3576b067f6 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h
@@ -496,6 +496,7 @@ static inline void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id)
}
struct bpf_verifier_log;
+struct bpf_struct_ops;
#ifdef CONFIG_BPF_SYSCALL
const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
@@ -520,6 +521,9 @@ btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
int get_kern_ctx_btf_id(struct bpf_verifier_log *log, enum bpf_prog_type prog_type);
bool btf_types_are_same(const struct btf *btf1, u32 id1,
const struct btf *btf2, u32 id2);
+int register_bpf_struct_ops(struct bpf_struct_ops *st_ops);
+const struct bpf_struct_ops_desc *bpf_struct_ops_find_value(struct btf *btf, u32 value_id);
+const struct bpf_struct_ops_desc *bpf_struct_ops_find(struct btf *btf, u32 type_id);
#else
static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
u32 type_id)
@@ -572,6 +576,14 @@ static inline bool btf_types_are_same(const struct btf *btf1, u32 id1,
{
return false;
}
+static inline int register_bpf_struct_ops(struct bpf_struct_ops *st_ops)
+{
+ return -ENOTSUPP;
+}
+static inline const struct bpf_struct_ops_desc *bpf_struct_ops_find(struct btf *btf, u32 type_id)
+{
+ return NULL;
+}
#endif
static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t)
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index f5763f240722..1ebd7e3acb67 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -62,35 +62,6 @@ static DEFINE_MUTEX(update_mutex);
#define VALUE_PREFIX "bpf_struct_ops_"
#define VALUE_PREFIX_LEN (sizeof(VALUE_PREFIX) - 1)
-/* bpf_struct_ops_##_name (e.g. bpf_struct_ops_tcp_congestion_ops) is
- * the map's value exposed to the userspace and its btf-type-id is
- * stored at the map->btf_vmlinux_value_type_id.
- *
- */
-#define BPF_STRUCT_OPS_TYPE(_name) \
-extern struct bpf_struct_ops bpf_##_name; \
- \
-struct bpf_struct_ops_##_name { \
- struct bpf_struct_ops_common_value common; \
- struct _name data ____cacheline_aligned_in_smp; \
-};
-#include "bpf_struct_ops_types.h"
-#undef BPF_STRUCT_OPS_TYPE
-
-enum {
-#define BPF_STRUCT_OPS_TYPE(_name) BPF_STRUCT_OPS_TYPE_##_name,
-#include "bpf_struct_ops_types.h"
-#undef BPF_STRUCT_OPS_TYPE
- __NR_BPF_STRUCT_OPS_TYPE,
-};
-
-static struct bpf_struct_ops_desc bpf_struct_ops[] = {
-#define BPF_STRUCT_OPS_TYPE(_name) \
- [BPF_STRUCT_OPS_TYPE_##_name] = { .st_ops = &bpf_##_name },
-#include "bpf_struct_ops_types.h"
-#undef BPF_STRUCT_OPS_TYPE
-};
-
const struct bpf_verifier_ops bpf_struct_ops_verifier_ops = {
};
@@ -145,9 +116,9 @@ static bool is_valid_value_type(struct btf *btf, s32 value_id,
return true;
}
-static void bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
- struct btf *btf,
- struct bpf_verifier_log *log)
+int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
+ struct btf *btf,
+ struct bpf_verifier_log *log)
{
struct bpf_struct_ops *st_ops = st_ops_desc->st_ops;
const struct btf_member *member;
@@ -161,7 +132,7 @@ static void bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
sizeof(value_name)) {
pr_warn("struct_ops name %s is too long\n",
st_ops->name);
- return;
+ return -EINVAL;
}
sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
@@ -170,13 +141,13 @@ static void bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
if (type_id < 0) {
pr_warn("Cannot find struct %s in %s\n",
st_ops->name, btf_get_name(btf));
- return;
+ return -EINVAL;
}
t = btf_type_by_id(btf, type_id);
if (btf_type_vlen(t) > BPF_STRUCT_OPS_MAX_NR_MEMBERS) {
pr_warn("Cannot support #%u members in struct %s\n",
btf_type_vlen(t), st_ops->name);
- return;
+ return -EINVAL;
}
value_id = btf_find_by_name_kind(btf, value_name,
@@ -184,10 +155,10 @@ static void bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
if (value_id < 0) {
pr_warn("Cannot find struct %s in %s\n",
value_name, btf_get_name(btf));
- return;
+ return -EINVAL;
}
if (!is_valid_value_type(btf, value_id, t, value_name))
- return;
+ return -EINVAL;
for_each_member(i, t, member) {
const struct btf_type *func_proto;
@@ -196,13 +167,13 @@ static void bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
if (!*mname) {
pr_warn("anon member in struct %s is not supported\n",
st_ops->name);
- break;
+ return -EOPNOTSUPP;
}
if (__btf_member_bitfield_size(t, member)) {
pr_warn("bit field member %s in struct %s is not supported\n",
mname, st_ops->name);
- break;
+ return -EOPNOTSUPP;
}
func_proto = btf_type_resolve_func_ptr(btf,
@@ -214,7 +185,7 @@ static void bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
&st_ops->func_models[i])) {
pr_warn("Error in parsing func ptr %s in struct %s\n",
mname, st_ops->name);
- break;
+ return -EINVAL;
}
}
@@ -222,6 +193,7 @@ static void bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
if (st_ops->init(btf)) {
pr_warn("Error in init bpf_struct_ops %s\n",
st_ops->name);
+ return -EINVAL;
} else {
st_ops_desc->type_id = type_id;
st_ops_desc->type = t;
@@ -230,54 +202,8 @@ static void bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
value_id);
}
}
-}
-void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
-{
- struct bpf_struct_ops_desc *st_ops_desc;
- u32 i;
-
- /* Ensure BTF type is emitted for "struct bpf_struct_ops_##_name" */
-#define BPF_STRUCT_OPS_TYPE(_name) BTF_TYPE_EMIT(struct bpf_struct_ops_##_name);
-#include "bpf_struct_ops_types.h"
-#undef BPF_STRUCT_OPS_TYPE
-
- for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
- st_ops_desc = &bpf_struct_ops[i];
- bpf_struct_ops_desc_init(st_ops_desc, btf, log);
- }
-}
-
-static const struct bpf_struct_ops_desc *
-bpf_struct_ops_find_value(struct btf *btf, u32 value_id)
-{
- unsigned int i;
-
- if (!value_id || !btf)
- return NULL;
-
- for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
- if (bpf_struct_ops[i].value_id == value_id)
- return &bpf_struct_ops[i];
- }
-
- return NULL;
-}
-
-const struct bpf_struct_ops_desc *
-bpf_struct_ops_find(struct btf *btf, u32 type_id)
-{
- unsigned int i;
-
- if (!type_id || !btf)
- return NULL;
-
- for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
- if (bpf_struct_ops[i].type_id == type_id)
- return &bpf_struct_ops[i];
- }
-
- return NULL;
+ return 0;
}
static int bpf_struct_ops_map_get_next_key(struct bpf_map *map, void *key,
diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h
deleted file mode 100644
index 5678a9ddf817..000000000000
--- a/kernel/bpf/bpf_struct_ops_types.h
+++ /dev/null
@@ -1,12 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/* internal file - do not include directly */
-
-#ifdef CONFIG_BPF_JIT
-#ifdef CONFIG_NET
-BPF_STRUCT_OPS_TYPE(bpf_dummy_ops)
-#endif
-#ifdef CONFIG_INET
-#include <net/tcp.h>
-BPF_STRUCT_OPS_TYPE(tcp_congestion_ops)
-#endif
-#endif
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 3fa84c44b882..860b2946de3c 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -19,6 +19,7 @@
#include <linux/bpf_verifier.h>
#include <linux/btf.h>
#include <linux/btf_ids.h>
+#include <linux/bpf.h>
#include <linux/bpf_lsm.h>
#include <linux/skmsg.h>
#include <linux/perf_event.h>
@@ -5792,8 +5793,6 @@ struct btf *btf_parse_vmlinux(void)
/* btf_parse_vmlinux() runs under bpf_verifier_lock */
bpf_ctx_convert.t = btf_type_by_id(btf, bpf_ctx_convert_btf_id[0]);
- bpf_struct_ops_init(btf, log);
-
refcount_set(&btf->refcnt, 1);
err = btf_alloc_id(btf);
@@ -8489,10 +8488,11 @@ bool btf_type_ids_nocast_alias(struct bpf_verifier_log *log,
}
static int
-btf_add_struct_ops(struct btf *btf, struct bpf_struct_ops *st_ops)
+btf_add_struct_ops(struct btf *btf, struct bpf_struct_ops *st_ops,
+ struct bpf_verifier_log *log)
{
struct btf_struct_ops_tab *tab, *new_tab;
- int i;
+ int i, err;
if (!btf)
return -ENOENT;
@@ -8529,7 +8529,83 @@ btf_add_struct_ops(struct btf *btf, struct bpf_struct_ops *st_ops)
tab->ops[btf->struct_ops_tab->cnt].st_ops = st_ops;
+ err = bpf_struct_ops_desc_init(&tab->ops[btf->struct_ops_tab->cnt], btf, log);
+ if (err)
+ return err;
+
btf->struct_ops_tab->cnt++;
return 0;
}
+
+const struct bpf_struct_ops_desc *
+bpf_struct_ops_find_value(struct btf *btf, u32 value_id)
+{
+ const struct bpf_struct_ops_desc *st_ops_list;
+ unsigned int i;
+ u32 cnt;
+
+ if (!value_id)
+ return NULL;
+ if (!btf->struct_ops_tab)
+ return NULL;
+
+ cnt = btf->struct_ops_tab->cnt;
+ st_ops_list = btf->struct_ops_tab->ops;
+ for (i = 0; i < cnt; i++) {
+ if (st_ops_list[i].value_id == value_id)
+ return &st_ops_list[i];
+ }
+
+ return NULL;
+}
+
+const struct bpf_struct_ops_desc *
+bpf_struct_ops_find(struct btf *btf, u32 type_id)
+{
+ const struct bpf_struct_ops_desc *st_ops_list;
+ unsigned int i;
+ u32 cnt;
+
+ if (!type_id)
+ return NULL;
+ if (!btf->struct_ops_tab)
+ return NULL;
+
+ cnt = btf->struct_ops_tab->cnt;
+ st_ops_list = btf->struct_ops_tab->ops;
+ for (i = 0; i < cnt; i++) {
+ if (st_ops_list[i].type_id == type_id)
+ return &st_ops_list[i];
+ }
+
+ return NULL;
+}
+
+int register_bpf_struct_ops(struct bpf_struct_ops *st_ops)
+{
+ struct bpf_verifier_log *log;
+ struct btf *btf;
+ int err = 0;
+
+ btf = btf_get_module_btf(st_ops->owner);
+ if (!btf)
+ return -EINVAL;
+
+ log = kzalloc(sizeof(*log), GFP_KERNEL | __GFP_NOWARN);
+ if (!log) {
+ err = -ENOMEM;
+ goto errout;
+ }
+
+ log->level = BPF_LOG_KERNEL;
+
+ err = btf_add_struct_ops(btf, st_ops, log);
+
+errout:
+ kfree(log);
+ btf_put(btf);
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(register_bpf_struct_ops);
diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c
index ba2c58dba2da..42034c54a70f 100644
--- a/net/bpf/bpf_dummy_struct_ops.c
+++ b/net/bpf/bpf_dummy_struct_ops.c
@@ -7,7 +7,7 @@
#include <linux/bpf.h>
#include <linux/btf.h>
-extern struct bpf_struct_ops bpf_bpf_dummy_ops;
+static struct bpf_struct_ops bpf_bpf_dummy_ops;
/* A common type for test_N with return value in bpf_dummy_ops */
typedef int (*dummy_ops_test_ret_fn)(struct bpf_dummy_ops_state *state, ...);
@@ -256,7 +256,7 @@ static struct bpf_dummy_ops __bpf_bpf_dummy_ops = {
.test_sleepable = bpf_dummy_test_sleepable,
};
-struct bpf_struct_ops bpf_bpf_dummy_ops = {
+static struct bpf_struct_ops bpf_bpf_dummy_ops = {
.verifier_ops = &bpf_dummy_verifier_ops,
.init = bpf_dummy_init,
.check_member = bpf_dummy_ops_check_member,
@@ -265,4 +265,11 @@ struct bpf_struct_ops bpf_bpf_dummy_ops = {
.unreg = bpf_dummy_unreg,
.name = "bpf_dummy_ops",
.cfi_stubs = &__bpf_bpf_dummy_ops,
+ .owner = THIS_MODULE,
};
+
+static int __init bpf_dummy_struct_ops_init(void)
+{
+ return REGISTER_BPF_STRUCT_OPS(&bpf_bpf_dummy_ops, bpf_dummy_ops);
+}
+late_initcall(bpf_dummy_struct_ops_init);
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index dffd8828079b..7e053b9faca3 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -12,7 +12,7 @@
#include <net/bpf_sk_storage.h>
/* "extern" is to avoid sparse warning. It is only used in bpf_struct_ops.c. */
-extern struct bpf_struct_ops bpf_tcp_congestion_ops;
+static struct bpf_struct_ops bpf_tcp_congestion_ops;
static u32 unsupported_ops[] = {
offsetof(struct tcp_congestion_ops, get_info),
@@ -345,7 +345,7 @@ static struct tcp_congestion_ops __bpf_ops_tcp_congestion_ops = {
.release = __bpf_tcp_ca_release,
};
-struct bpf_struct_ops bpf_tcp_congestion_ops = {
+static struct bpf_struct_ops bpf_tcp_congestion_ops = {
.verifier_ops = &bpf_tcp_ca_verifier_ops,
.reg = bpf_tcp_ca_reg,
.unreg = bpf_tcp_ca_unreg,
@@ -356,10 +356,16 @@ struct bpf_struct_ops bpf_tcp_congestion_ops = {
.validate = bpf_tcp_ca_validate,
.name = "tcp_congestion_ops",
.cfi_stubs = &__bpf_ops_tcp_congestion_ops,
+ .owner = THIS_MODULE,
};
static int __init bpf_tcp_ca_kfunc_init(void)
{
- return register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &bpf_tcp_ca_kfunc_set);
+ int ret;
+
+ ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &bpf_tcp_ca_kfunc_set);
+ ret = ret ?: REGISTER_BPF_STRUCT_OPS(&bpf_tcp_congestion_ops, tcp_congestion_ops);
+
+ return ret;
}
late_initcall(bpf_tcp_ca_kfunc_init);
--
2.34.1
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