linux-kernel - [PATCH RFC bpf-next 8/8] bpf: rely on __aux suffix for bpf_wq_set_callback

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Message-Id: <20240507-bpf_async-v1-8-b4df966096d8@kernel.org>
Date: Tue, 07 May 2024 15:19:36 +0200
From: Benjamin Tissoires <bentiss@...nel.org>
To: Alexei Starovoitov <ast@...nel.org>, 
 Daniel Borkmann <daniel@...earbox.net>, 
 John Fastabend <john.fastabend@...il.com>, 
 Andrii Nakryiko <andrii@...nel.org>, 
 Martin KaFai Lau <martin.lau@...ux.dev>, 
 Eduard Zingerman <eddyz87@...il.com>, Song Liu <song@...nel.org>, 
 Yonghong Song <yonghong.song@...ux.dev>, KP Singh <kpsingh@...nel.org>, 
 Stanislav Fomichev <sdf@...gle.com>, Hao Luo <haoluo@...gle.com>, 
 Jiri Olsa <jolsa@...nel.org>, Mykola Lysenko <mykolal@...com>, 
 Shuah Khan <shuah@...nel.org>
Cc: bpf@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-kselftest@...r.kernel.org, Benjamin Tissoires <bentiss@...nel.org>
Subject: [PATCH RFC bpf-next 8/8] bpf: rely on __aux suffix for
 bpf_wq_set_callback_impl

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

Signed-off-by: Benjamin Tissoires <bentiss@...nel.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