[PATCH RFC bpf-next 8/8] bpf: rely on __aux suffix for bpf_wq_set_callback_impl

Benjamin Tissoires
2024-05-07T13:20:13Z

And then cleanup the verifier about the special cases about this kfunc.

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>

---

This is an RFC, and is not meant to be fully reviewed/applied as it is.
I'm posting this to show what I wanted to explain in
https://lore.kernel.org/bpf/mhkzkf4e23uvljtmwizwcxyuyat2tmfxn33xb4t7waafgmsa66@mcrzpj3b6ssx/
---
kernel/bpf/helpers.c | 4 ++--
kernel/bpf/verifier.c | 17 -----------------
2 files changed, 2 insertions(+), 19 deletions(-)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 97628bcbd507..03524fa5feef 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2725,9 +2725,9 @@ typedef int (*wq_callback_fn_t)(struct bpf_map *map, int *key, struct bpf_wq *wq
__bpf_kfunc int bpf_wq_set_callback_impl(struct bpf_wq *wq,
wq_callback_fn_t callback_fn__s_async,
unsigned int flags,
- void *aux__ign)
+ void *prog__aux)
{
- struct bpf_prog_aux *aux = (struct bpf_prog_aux *)aux__ign;
+ struct bpf_prog_aux *aux = (struct bpf_prog_aux *)prog__aux;
struct bpf_async_kern *async = (struct bpf_async_kern *)wq;

if (flags)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 33b108db0025..829a234832d9 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -514,8 +514,6 @@ static bool is_sync_callback_calling_kfunc(u32 btf_id);
static bool is_callback_calling_kfunc(u32 btf_id);
static bool is_bpf_throw_kfunc(struct bpf_insn *insn);

-static bool is_bpf_wq_set_callback_impl_kfunc(u32 btf_id);
-
static bool is_sync_callback_calling_function(enum bpf_func_id func_id)
{
return func_id == BPF_FUNC_for_each_map_elem ||
@@ -11134,7 +11132,6 @@ enum special_kfunc_type {
KF_bpf_percpu_obj_new_impl,
KF_bpf_percpu_obj_drop_impl,
KF_bpf_throw,
- KF_bpf_wq_set_callback_impl,
KF_bpf_preempt_disable,
KF_bpf_preempt_enable,
KF_bpf_iter_css_task_new,
@@ -11161,7 +11158,6 @@ BTF_ID(func, bpf_dynptr_clone)
BTF_ID(func, bpf_percpu_obj_new_impl)
BTF_ID(func, bpf_percpu_obj_drop_impl)
BTF_ID(func, bpf_throw)
-BTF_ID(func, bpf_wq_set_callback_impl)
#ifdef CONFIG_CGROUPS
BTF_ID(func, bpf_iter_css_task_new)
#endif
@@ -11190,7 +11186,6 @@ BTF_ID(func, bpf_dynptr_clone)
BTF_ID(func, bpf_percpu_obj_new_impl)
BTF_ID(func, bpf_percpu_obj_drop_impl)
BTF_ID(func, bpf_throw)
-BTF_ID(func, bpf_wq_set_callback_impl)
BTF_ID(func, bpf_preempt_disable)
BTF_ID(func, bpf_preempt_enable)
#ifdef CONFIG_CGROUPS
@@ -11542,11 +11537,6 @@ static bool is_bpf_throw_kfunc(struct bpf_insn *insn)
insn->imm == special_kfunc_list[KF_bpf_throw];
}

-static bool is_bpf_wq_set_callback_impl_kfunc(u32 btf_id)
-{
- return btf_id == special_kfunc_list[KF_bpf_wq_set_callback_impl];
-}
-
static bool is_callback_calling_kfunc(u32 btf_id)
{
return is_sync_callback_calling_kfunc(btf_id);
@@ -19949,13 +19939,6 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
desc->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1);
*cnt = 1;
- } else if (is_bpf_wq_set_callback_impl_kfunc(desc->func_id)) {
- struct bpf_insn ld_addrs[2] = { BPF_LD_IMM64(BPF_REG_4, (long)env->prog->aux) };
-
- insn_buf[0] = ld_addrs[0];
- insn_buf[1] = ld_addrs[1];
- insn_buf[2] = *insn;
- *cnt = 3;
} else {
struct bpf_kfunc_call_arg_meta meta;
struct bpf_insn kfunc_insn = *insn;

--
2.44.0