From: Kui-Feng Lee <thinker.li@xxxxxxxxx>
A value_type should consist of three components: refcnt, state, and data.
refcnt and state has been move to struct bpf_struct_ops_common_value to
make it easier to check the value type.
Signed-off-by: Kui-Feng Lee <thinker.li@xxxxxxxxx>
---
kernel/bpf/bpf_struct_ops.c | 86 ++++++++++++++++++++++++++++---------
1 file changed, 65 insertions(+), 21 deletions(-)
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 413a3f8b26ba..6367d42b2ce1 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -20,9 +20,11 @@ enum bpf_struct_ops_state {
BPF_STRUCT_OPS_STATE_READY,
};
-#define BPF_STRUCT_OPS_COMMON_VALUE \
- refcount_t refcnt; \
- enum bpf_struct_ops_state state
+struct bpf_struct_ops_common_value {
+ refcount_t refcnt;
+ enum bpf_struct_ops_state state;
+};
+#define BPF_STRUCT_OPS_COMMON_VALUE struct bpf_struct_ops_common_value common
struct bpf_struct_ops_value {
BPF_STRUCT_OPS_COMMON_VALUE;
@@ -109,6 +111,38 @@ const struct bpf_prog_ops bpf_struct_ops_prog_ops = {
};
static const struct btf_type *module_type;
+static const struct btf_type *common_value_type;
+
+static bool is_valid_value_type(struct btf *btf, s32 value_id,
+ const struct btf_type *type,
+ const char *value_name)
+{
+ const struct btf_member *member;
+ const struct btf_type *vt, *mt;
+
+ vt = btf_type_by_id(btf, value_id);
+ if (btf_vlen(vt) != 2) {
+ pr_warn("The number of %s's members should be 2, but we get %d\n",
+ value_name, btf_vlen(vt));
+ return false;
+ }
+ member = btf_type_member(vt);
+ mt = btf_type_by_id(btf, member->type);
+ if (mt != common_value_type) {
+ pr_warn("The first member of %s should be bpf_struct_ops_common_value\n",
+ value_name);
+ return false;
+ }
+ member++;
+ mt = btf_type_by_id(btf, member->type);
+ if (mt != type) {
+ pr_warn("The second member of %s should be %s\n",
+ value_name, btf_name_by_offset(btf, type->name_off));
+ return false;
+ }
+
+ return true;
+}
static void bpf_struct_ops_init_one(struct bpf_struct_ops_desc *st_ops_desc,
struct btf *btf,
@@ -130,14 +164,6 @@ static void bpf_struct_ops_init_one(struct bpf_struct_ops_desc *st_ops_desc,
}
sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
- value_id = btf_find_by_name_kind(btf, value_name,
- BTF_KIND_STRUCT);
- if (value_id < 0) {
- pr_warn("Cannot find struct %s in btf_vmlinux\n",
- value_name);
- return;
- }
-
type_id = btf_find_by_name_kind(btf, st_ops->name,
BTF_KIND_STRUCT);
if (type_id < 0) {
@@ -152,6 +178,16 @@ static void bpf_struct_ops_init_one(struct bpf_struct_ops_desc *st_ops_desc,
return;
}
+ value_id = btf_find_by_name_kind(btf, value_name,
+ BTF_KIND_STRUCT);
+ if (value_id < 0) {
+ pr_warn("Cannot find struct %s in btf_vmlinux\n",
+ value_name);
+ return;
+ }
+ if (!is_valid_value_type(btf, value_id, t, value_name))
+ return;
+
for_each_member(i, t, member) {
const struct btf_type *func_proto;
@@ -199,7 +235,7 @@ static void bpf_struct_ops_init_one(struct bpf_struct_ops_desc *st_ops_desc,
void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
{
struct bpf_struct_ops_desc *st_ops_desc;
- s32 module_id;
+ s32 module_id, common_value_id;
u32 i;
/* Ensure BTF type is emitted for "struct bpf_struct_ops_##_name" */
@@ -213,6 +249,14 @@ void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
return;
}
module_type = btf_type_by_id(btf, module_id);
+ common_value_id = btf_find_by_name_kind(btf,
+ "bpf_struct_ops_common_value",
+ BTF_KIND_STRUCT);
+ if (common_value_id < 0) {
+ pr_warn("Cannot find struct common_value in btf_vmlinux\n");
+ return;
+ }
+ common_value_type = btf_type_by_id(btf, common_value_id);
for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
st_ops_desc = &bpf_struct_ops[i];
@@ -277,7 +321,7 @@ int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key,
kvalue = &st_map->kvalue;
/* Pair with smp_store_release() during map_update */
- state = smp_load_acquire(&kvalue->state);
+ state = smp_load_acquire(&kvalue->common.state);
if (state == BPF_STRUCT_OPS_STATE_INIT) {
memset(value, 0, map->value_size);
return 0;
@@ -288,7 +332,7 @@ int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key,
*/
uvalue = value;
memcpy(uvalue, st_map->uvalue, map->value_size);
- uvalue->state = state;
+ uvalue->common.state = state;
/* This value offers the user space a general estimate of how
* many sockets are still utilizing this struct_ops for TCP
@@ -296,7 +340,7 @@ int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key,
* should sufficiently meet our present goals.
*/
refcnt = atomic64_read(&map->refcnt) - atomic64_read(&map->usercnt);
- refcount_set(&uvalue->refcnt, max_t(s64, refcnt, 0));
+ refcount_set(&uvalue->common.refcnt, max_t(s64, refcnt, 0));
return 0;
}
@@ -409,7 +453,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
if (err)
return err;
- if (uvalue->state || refcount_read(&uvalue->refcnt))
+ if (uvalue->common.state || refcount_read(&uvalue->common.refcnt))
return -EINVAL;
tlinks = kcalloc(BPF_TRAMP_MAX, sizeof(*tlinks), GFP_KERNEL);
@@ -421,7 +465,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
mutex_lock(&st_map->lock);
- if (kvalue->state != BPF_STRUCT_OPS_STATE_INIT) {
+ if (kvalue->common.state != BPF_STRUCT_OPS_STATE_INIT) {
err = -EBUSY;
goto unlock;
}
@@ -542,7 +586,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
*
* Pair with smp_load_acquire() during lookup_elem().
*/
- smp_store_release(&kvalue->state, BPF_STRUCT_OPS_STATE_READY);
+ smp_store_release(&kvalue->common.state, BPF_STRUCT_OPS_STATE_READY);
goto unlock;
}
@@ -560,7 +604,7 @@ static long bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
* It ensures the above udata updates (e.g. prog->aux->id)
* can be seen once BPF_STRUCT_OPS_STATE_INUSE is set.
*/
- smp_store_release(&kvalue->state, BPF_STRUCT_OPS_STATE_INUSE);
+ smp_store_release(&kvalue->common.state, BPF_STRUCT_OPS_STATE_INUSE);
/* Hold the owner module until the struct_ops is
* unregistered
*/
@@ -596,7 +640,7 @@ static long bpf_struct_ops_map_delete_elem(struct bpf_map *map, void *key)
if (st_map->map.map_flags & BPF_F_LINK)
return -EOPNOTSUPP;
- prev_state = cmpxchg(&st_map->kvalue.state,
+ prev_state = cmpxchg(&st_map->kvalue.common.state,
BPF_STRUCT_OPS_STATE_INUSE,
BPF_STRUCT_OPS_STATE_TOBEFREE);
switch (prev_state) {
@@ -828,7 +872,7 @@ static bool bpf_struct_ops_valid_to_reg(struct bpf_map *map)
return map->map_type == BPF_MAP_TYPE_STRUCT_OPS &&
map->map_flags & BPF_F_LINK &&
/* Pair with smp_store_release() during map_update */
- smp_load_acquire(&st_map->kvalue.state) == BPF_STRUCT_OPS_STATE_READY;
+ smp_load_acquire(&st_map->kvalue.common.state) == BPF_STRUCT_OPS_STATE_READY;
}
static void bpf_struct_ops_map_link_dealloc(struct bpf_link *link)
--
2.34.1
