bpf: Migrate bpf_task_work_schedule_* kfuncs to KF_IMPLICIT_ARGS

Implement bpf_task_work_schedule_* with an implicit bpf_prog_aux
argument, and remove corresponding _impl funcs from the kernel.

Update special kfunc checks in the verifier accordingly.

Update the selftests to use the new API with implicit argument.

Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-10-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2 files changed, 20 insertions, 22 deletions

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index c76a9003b221..f2f974b5fb3b 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -4274,41 +4274,39 @@ release_prog:
 }
 
 /**
- * bpf_task_work_schedule_signal_impl - Schedule BPF callback using task_work_add with TWA_SIGNAL
+ * bpf_task_work_schedule_signal - Schedule BPF callback using task_work_add with TWA_SIGNAL
  * mode
  * @task: Task struct for which callback should be scheduled
  * @tw: Pointer to struct bpf_task_work in BPF map value for internal bookkeeping
  * @map__map: bpf_map that embeds struct bpf_task_work in the values
  * @callback: pointer to BPF subprogram to call
- * @aux__prog: user should pass NULL
+ * @aux: pointer to bpf_prog_aux of the caller BPF program, implicitly set by the verifier
  *
  * Return: 0 if task work has been scheduled successfully, negative error code otherwise
  */
-__bpf_kfunc int bpf_task_work_schedule_signal_impl(struct task_struct *task,
-						   struct bpf_task_work *tw, void *map__map,
-						   bpf_task_work_callback_t callback,
-						   void *aux__prog)
+__bpf_kfunc int bpf_task_work_schedule_signal(struct task_struct *task, struct bpf_task_work *tw,
+					      void *map__map, bpf_task_work_callback_t callback,
+					      struct bpf_prog_aux *aux)
 {
-	return bpf_task_work_schedule(task, tw, map__map, callback, aux__prog, TWA_SIGNAL);
+	return bpf_task_work_schedule(task, tw, map__map, callback, aux, TWA_SIGNAL);
 }
 
 /**
- * bpf_task_work_schedule_resume_impl - Schedule BPF callback using task_work_add with TWA_RESUME
+ * bpf_task_work_schedule_resume - Schedule BPF callback using task_work_add with TWA_RESUME
  * mode
  * @task: Task struct for which callback should be scheduled
  * @tw: Pointer to struct bpf_task_work in BPF map value for internal bookkeeping
  * @map__map: bpf_map that embeds struct bpf_task_work in the values
  * @callback: pointer to BPF subprogram to call
- * @aux__prog: user should pass NULL
+ * @aux: pointer to bpf_prog_aux of the caller BPF program, implicitly set by the verifier
  *
  * Return: 0 if task work has been scheduled successfully, negative error code otherwise
  */
-__bpf_kfunc int bpf_task_work_schedule_resume_impl(struct task_struct *task,
-						   struct bpf_task_work *tw, void *map__map,
-						   bpf_task_work_callback_t callback,
-						   void *aux__prog)
+__bpf_kfunc int bpf_task_work_schedule_resume(struct task_struct *task, struct bpf_task_work *tw,
+					      void *map__map, bpf_task_work_callback_t callback,
+					      struct bpf_prog_aux *aux)
 {
-	return bpf_task_work_schedule(task, tw, map__map, callback, aux__prog, TWA_RESUME);
+	return bpf_task_work_schedule(task, tw, map__map, callback, aux, TWA_RESUME);
 }
 
 static int make_file_dynptr(struct file *file, u32 flags, bool may_sleep,
@@ -4536,8 +4534,8 @@ BTF_ID_FLAGS(func, bpf_strncasestr);
 BTF_ID_FLAGS(func, bpf_cgroup_read_xattr, KF_RCU)
 #endif
 BTF_ID_FLAGS(func, bpf_stream_vprintk_impl)
-BTF_ID_FLAGS(func, bpf_task_work_schedule_signal_impl)
-BTF_ID_FLAGS(func, bpf_task_work_schedule_resume_impl)
+BTF_ID_FLAGS(func, bpf_task_work_schedule_signal, KF_IMPLICIT_ARGS)
+BTF_ID_FLAGS(func, bpf_task_work_schedule_resume, KF_IMPLICIT_ARGS)
 BTF_ID_FLAGS(func, bpf_dynptr_from_file)
 BTF_ID_FLAGS(func, bpf_dynptr_file_discard)
 BTF_KFUNCS_END(common_btf_ids)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 51e8c9f70868..8e8570e9d167 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -12457,8 +12457,8 @@ enum special_kfunc_type {
 	KF_bpf_dynptr_from_file,
 	KF_bpf_dynptr_file_discard,
 	KF___bpf_trap,
-	KF_bpf_task_work_schedule_signal_impl,
-	KF_bpf_task_work_schedule_resume_impl,
+	KF_bpf_task_work_schedule_signal,
+	KF_bpf_task_work_schedule_resume,
 	KF_bpf_arena_alloc_pages,
 	KF_bpf_arena_free_pages,
 	KF_bpf_arena_reserve_pages,
@@ -12534,16 +12534,16 @@ BTF_ID(func, bpf_res_spin_unlock_irqrestore)
 BTF_ID(func, bpf_dynptr_from_file)
 BTF_ID(func, bpf_dynptr_file_discard)
 BTF_ID(func, __bpf_trap)
-BTF_ID(func, bpf_task_work_schedule_signal_impl)
-BTF_ID(func, bpf_task_work_schedule_resume_impl)
+BTF_ID(func, bpf_task_work_schedule_signal)
+BTF_ID(func, bpf_task_work_schedule_resume)
 BTF_ID(func, bpf_arena_alloc_pages)
 BTF_ID(func, bpf_arena_free_pages)
 BTF_ID(func, bpf_arena_reserve_pages)
 
 static bool is_task_work_add_kfunc(u32 func_id)
 {
-	return func_id == special_kfunc_list[KF_bpf_task_work_schedule_signal_impl] ||
-	       func_id == special_kfunc_list[KF_bpf_task_work_schedule_resume_impl];
+	return func_id == special_kfunc_list[KF_bpf_task_work_schedule_signal] ||
+	       func_id == special_kfunc_list[KF_bpf_task_work_schedule_resume];
 }
 
 static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)