[PATCH bpf-next v2 05/11] bpf: Share map-backed callback register setup
From: Ihor Solodrai
Date: Fri Oct 09 2026 - 16:31:48 EST
Map iteration, timer, task-work and RCU callbacks repeat the same register
type, offset and map-metadata setup for their map, key and value arguments.
Use one initializer for map-backed callback registers. Leave argument
selection, value ids and callback-specific policy in each setter.
No functional change.
Signed-off-by: Ihor Solodrai <ihor.solodrai@xxxxxxxxx>
---
kernel/bpf/verifier.c | 81 +++++++++++--------------------------------
1 file changed, 21 insertions(+), 60 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 88b86f658e4a..8f2125c6e348 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11267,6 +11267,16 @@ static int check_func_callx(struct bpf_verifier_env *env, struct bpf_insn *insn,
return check_static_func_call(env, subprog, insn_idx);
}
+static void mark_map_callback_reg(struct bpf_reg_state *reg,
+ const struct bpf_reg_state *map_reg,
+ enum bpf_reg_type type)
+{
+ reg->type = type;
+ __mark_reg_known_zero(reg);
+ reg->map_ptr = map_reg->map_ptr;
+ reg->map_uid = map_reg->map_uid;
+}
+
int map_set_for_each_callback_args(struct bpf_verifier_env *env,
struct bpf_verifier_state *state,
struct bpf_func_state *caller,
@@ -11279,15 +11289,8 @@ int map_set_for_each_callback_args(struct bpf_verifier_env *env,
*/
callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
- callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
- __mark_reg_known_zero(&callee->regs[BPF_REG_2]);
- callee->regs[BPF_REG_2].map_ptr = caller->regs[BPF_REG_1].map_ptr;
- callee->regs[BPF_REG_2].map_uid = caller->regs[BPF_REG_1].map_uid;
-
- callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
- __mark_reg_known_zero(&callee->regs[BPF_REG_3]);
- callee->regs[BPF_REG_3].map_ptr = caller->regs[BPF_REG_1].map_ptr;
- callee->regs[BPF_REG_3].map_uid = caller->regs[BPF_REG_1].map_uid;
+ mark_map_callback_reg(&callee->regs[BPF_REG_2], &caller->regs[BPF_REG_1], PTR_TO_MAP_KEY);
+ mark_map_callback_reg(&callee->regs[BPF_REG_3], &caller->regs[BPF_REG_1], PTR_TO_MAP_VALUE);
callee->regs[BPF_REG_3].id = ++env->id_gen;
/* pointer to stack or null */
@@ -11354,26 +11357,12 @@ static int set_timer_callback_state(struct bpf_verifier_env *env,
struct bpf_func_state *callee,
int insn_idx)
{
- struct bpf_map *map_ptr = caller->regs[BPF_REG_1].map_ptr;
- u32 map_uid = caller->regs[BPF_REG_1].map_uid;
-
/* bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn);
* callback_fn(struct bpf_map *map, void *key, void *value);
*/
- callee->regs[BPF_REG_1].type = CONST_PTR_TO_MAP;
- __mark_reg_known_zero(&callee->regs[BPF_REG_1]);
- callee->regs[BPF_REG_1].map_ptr = map_ptr;
- callee->regs[BPF_REG_1].map_uid = map_uid;
-
- callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
- __mark_reg_known_zero(&callee->regs[BPF_REG_2]);
- callee->regs[BPF_REG_2].map_ptr = map_ptr;
- callee->regs[BPF_REG_2].map_uid = map_uid;
-
- callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
- __mark_reg_known_zero(&callee->regs[BPF_REG_3]);
- callee->regs[BPF_REG_3].map_ptr = map_ptr;
- callee->regs[BPF_REG_3].map_uid = map_uid;
+ mark_map_callback_reg(&callee->regs[BPF_REG_1], &caller->regs[BPF_REG_1], CONST_PTR_TO_MAP);
+ mark_map_callback_reg(&callee->regs[BPF_REG_2], &caller->regs[BPF_REG_1], PTR_TO_MAP_KEY);
+ mark_map_callback_reg(&callee->regs[BPF_REG_3], &caller->regs[BPF_REG_1], PTR_TO_MAP_VALUE);
callee->regs[BPF_REG_3].id = ++env->id_gen;
/* unused */
@@ -11477,26 +11466,12 @@ static int set_task_work_schedule_callback_state(struct bpf_verifier_env *env,
struct bpf_func_state *callee,
int insn_idx)
{
- struct bpf_map *map_ptr = caller->regs[BPF_REG_3].map_ptr;
- u32 map_uid = caller->regs[BPF_REG_3].map_uid;
-
/*
* callback_fn(struct bpf_map *map, void *key, void *value);
*/
- callee->regs[BPF_REG_1].type = CONST_PTR_TO_MAP;
- __mark_reg_known_zero(&callee->regs[BPF_REG_1]);
- callee->regs[BPF_REG_1].map_ptr = map_ptr;
- callee->regs[BPF_REG_1].map_uid = map_uid;
-
- callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
- __mark_reg_known_zero(&callee->regs[BPF_REG_2]);
- callee->regs[BPF_REG_2].map_ptr = map_ptr;
- callee->regs[BPF_REG_2].map_uid = map_uid;
-
- callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
- __mark_reg_known_zero(&callee->regs[BPF_REG_3]);
- callee->regs[BPF_REG_3].map_ptr = map_ptr;
- callee->regs[BPF_REG_3].map_uid = map_uid;
+ mark_map_callback_reg(&callee->regs[BPF_REG_1], &caller->regs[BPF_REG_3], CONST_PTR_TO_MAP);
+ mark_map_callback_reg(&callee->regs[BPF_REG_2], &caller->regs[BPF_REG_3], PTR_TO_MAP_KEY);
+ mark_map_callback_reg(&callee->regs[BPF_REG_3], &caller->regs[BPF_REG_3], PTR_TO_MAP_VALUE);
callee->regs[BPF_REG_3].id = ++env->id_gen;
/* unused */
@@ -11513,26 +11488,12 @@ static int set_rcu_callback_state(struct bpf_verifier_env *env,
struct bpf_func_state *callee,
int insn_idx)
{
- struct bpf_map *map_ptr = caller->regs[BPF_REG_2].map_ptr;
- u32 map_uid = caller->regs[BPF_REG_2].map_uid;
-
/*
* callback_fn(struct bpf_map *map, void *key, void *value);
*/
- callee->regs[BPF_REG_1].type = CONST_PTR_TO_MAP;
- __mark_reg_known_zero(&callee->regs[BPF_REG_1]);
- callee->regs[BPF_REG_1].map_ptr = map_ptr;
- callee->regs[BPF_REG_1].map_uid = map_uid;
-
- callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
- __mark_reg_known_zero(&callee->regs[BPF_REG_2]);
- callee->regs[BPF_REG_2].map_ptr = map_ptr;
- callee->regs[BPF_REG_2].map_uid = map_uid;
-
- callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
- __mark_reg_known_zero(&callee->regs[BPF_REG_3]);
- callee->regs[BPF_REG_3].map_ptr = map_ptr;
- callee->regs[BPF_REG_3].map_uid = map_uid;
+ mark_map_callback_reg(&callee->regs[BPF_REG_1], &caller->regs[BPF_REG_2], CONST_PTR_TO_MAP);
+ mark_map_callback_reg(&callee->regs[BPF_REG_2], &caller->regs[BPF_REG_2], PTR_TO_MAP_KEY);
+ mark_map_callback_reg(&callee->regs[BPF_REG_3], &caller->regs[BPF_REG_2], PTR_TO_MAP_VALUE);
/* unused */
bpf_mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
--
2.56.0