[PATCH bpf-next v4 1/7] bpf: pass bpf_struct_ops_link to callbacks in bpf_struct_ops.

Kui-Feng Lee
2024-05-21T22:53:02Z

Pass an additional pointer of bpf_struct_ops_link to callback function reg,
unreg, and update provided by subsystems defined in bpf_struct_ops. A
bpf_struct_ops_map can be registered for multiple links. Passing a pointer
of bpf_struct_ops_link helps subsystems to distinguish them.

This pointer will be used in the later patches to let the subsystem
initiate a detachment on a link that was registered to it previously.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
include/linux/bpf.h | 6 +++---
kernel/bpf/bpf_struct_ops.c | 10 +++++-----
net/bpf/bpf_dummy_struct_ops.c | 4 ++--
net/ipv4/bpf_tcp_ca.c | 6 +++---
.../selftests/bpf/bpf_test_no_cfi/bpf_test_no_cfi.c | 4 ++--
tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c | 6 +++---
6 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 90094400cc63..b600767ebe02 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1730,9 +1730,9 @@ struct bpf_struct_ops {
int (*init_member)(const struct btf_type *t,
const struct btf_member *member,
void *kdata, const void *udata);
- int (*reg)(void *kdata);
- void (*unreg)(void *kdata);
- int (*update)(void *kdata, void *old_kdata);
+ int (*reg)(void *kdata, struct bpf_link *link);
+ void (*unreg)(void *kdata, struct bpf_link *link);
+ int (*update)(void *kdata, void *old_kdata, struct bpf_link *link);
int (*validate)(void *kdata);
void *cfi_stubs;
struct module *owner;
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 86c7884abaf8..1542dded7489 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -757,7 +757,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
goto unlock;
}

- err = st_ops->reg(kdata);
+ err = st_ops->reg(kdata, NULL);
if (likely(!err)) {
/* This refcnt increment on the map here after
* 'st_ops->reg()' is secure since the state of the
@@ -805,7 +805,7 @@ static long bpf_struct_ops_map_delete_elem(struct bpf_map *map, void *key)
BPF_STRUCT_OPS_STATE_TOBEFREE);
switch (prev_state) {
case BPF_STRUCT_OPS_STATE_INUSE:
- st_map->st_ops_desc->st_ops->unreg(&st_map->kvalue.data);
+ st_map->st_ops_desc->st_ops->unreg(&st_map->kvalue.data, NULL);
bpf_map_put(map);
return 0;
case BPF_STRUCT_OPS_STATE_TOBEFREE:
@@ -1060,7 +1060,7 @@ static void bpf_struct_ops_map_link_dealloc(struct bpf_link *link)
/* st_link->map can be NULL if
* bpf_struct_ops_link_create() fails to register.
*/
- st_map->st_ops_desc->st_ops->unreg(&st_map->kvalue.data);
+ st_map->st_ops_desc->st_ops->unreg(&st_map->kvalue.data, link);
bpf_map_put(&st_map->map);
}
kfree(st_link);
@@ -1125,7 +1125,7 @@ static int bpf_struct_ops_map_link_update(struct bpf_link *link, struct bpf_map
goto err_out;
}

- err = st_map->st_ops_desc->st_ops->update(st_map->kvalue.data, old_st_map->kvalue.data);
+ err = st_map->st_ops_desc->st_ops->update(st_map->kvalue.data, old_st_map->kvalue.data, link);
if (err)
goto err_out;

@@ -1176,7 +1176,7 @@ int bpf_struct_ops_link_create(union bpf_attr *attr)
if (err)
goto err_out;

- err = st_map->st_ops_desc->st_ops->reg(st_map->kvalue.data);
+ err = st_map->st_ops_desc->st_ops->reg(st_map->kvalue.data, &link->link);
if (err) {
bpf_link_cleanup(&link_primer);
link = NULL;
diff --git a/net/bpf/bpf_dummy_struct_ops.c b/net/bpf/bpf_dummy_struct_ops.c
index 891cdf61c65a..3ea52b05adfb 100644
--- a/net/bpf/bpf_dummy_struct_ops.c
+++ b/net/bpf/bpf_dummy_struct_ops.c
@@ -272,12 +272,12 @@ static int bpf_dummy_init_member(const struct btf_type *t,
return -EOPNOTSUPP;
}

-static int bpf_dummy_reg(void *kdata)
+static int bpf_dummy_reg(void *kdata, struct bpf_link *link)
{
return -EOPNOTSUPP;
}

-static void bpf_dummy_unreg(void *kdata)
+static void bpf_dummy_unreg(void *kdata, struct bpf_link *link)
{
}

diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index 18227757ec0c..3f88d0961e5b 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -260,17 +260,17 @@ static int bpf_tcp_ca_check_member(const struct btf_type *t,
return 0;
}

-static int bpf_tcp_ca_reg(void *kdata)
+static int bpf_tcp_ca_reg(void *kdata, struct bpf_link *link)
{
return tcp_register_congestion_control(kdata);
}

-static void bpf_tcp_ca_unreg(void *kdata)
+static void bpf_tcp_ca_unreg(void *kdata, struct bpf_link *link)
{
tcp_unregister_congestion_control(kdata);
}

-static int bpf_tcp_ca_update(void *kdata, void *old_kdata)
+static int bpf_tcp_ca_update(void *kdata, void *old_kdata, struct bpf_link *link)
{
return tcp_update_congestion_control(kdata, old_kdata);
}
diff --git a/tools/testing/selftests/bpf/bpf_test_no_cfi/bpf_test_no_cfi.c b/tools/testing/selftests/bpf/bpf_test_no_cfi/bpf_test_no_cfi.c
index b1dd889d5d7d..948eb3962732 100644
--- a/tools/testing/selftests/bpf/bpf_test_no_cfi/bpf_test_no_cfi.c
+++ b/tools/testing/selftests/bpf/bpf_test_no_cfi/bpf_test_no_cfi.c
@@ -22,12 +22,12 @@ static int dummy_init_member(const struct btf_type *t,
return 0;
}

-static int dummy_reg(void *kdata)
+static int dummy_reg(void *kdata, struct bpf_link *link)
{
return 0;
}

-static void dummy_unreg(void *kdata)
+static void dummy_unreg(void *kdata, struct bpf_link *link)
{
}

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 2a18bd320e92..0a09732cde4b 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -820,7 +820,7 @@ static const struct bpf_verifier_ops bpf_testmod_verifier_ops = {
.is_valid_access = bpf_testmod_ops_is_valid_access,
};

-static int bpf_dummy_reg(void *kdata)
+static int bpf_dummy_reg(void *kdata, struct bpf_link *link)
{
struct bpf_testmod_ops *ops = kdata;

@@ -835,7 +835,7 @@ static int bpf_dummy_reg(void *kdata)
return 0;
}

-static void bpf_dummy_unreg(void *kdata)
+static void bpf_dummy_unreg(void *kdata, struct bpf_link *link)
{
}

@@ -871,7 +871,7 @@ struct bpf_struct_ops bpf_bpf_testmod_ops = {
.owner = THIS_MODULE,
};

-static int bpf_dummy_reg2(void *kdata)
+static int bpf_dummy_reg2(void *kdata, struct bpf_link *link)
{
struct bpf_testmod_ops2 *ops = kdata;

--
2.34.1