From: Kui-Feng Lee <sinquersw@gmail.com>
To: Martin KaFai Lau <martin.lau@linux.dev>, thinker.li@gmail.com
Cc: kuifeng@meta.com, bpf@vger.kernel.org, ast@kernel.org,
song@kernel.org, kernel-team@meta.com, andrii@kernel.org
Subject: Re: [RFC bpf-next v2 1/9] bpf: refactory struct_ops type initialization to a function.
Date: Fri, 15 Sep 2023 18:35:20 -0700 [thread overview]
Message-ID: <b181b09e-9d41-1574-1f12-31f7466c6e4c@gmail.com> (raw)
In-Reply-To: <34a6af4f-ef3d-7e34-0c71-3c76d8f299e2@linux.dev>
On 9/15/23 15:43, Martin KaFai Lau wrote:
> On 9/12/23 11:14 PM, thinker.li@gmail.com wrote:
>> From: Kui-Feng Lee <thinker.li@gmail.com>
>>
>> Move most of code to bpf_struct_ops_init_one() that can be use to
>> initialize new struct_ops types registered dynamically.
>
> While in RFC, still better to have SOB so that it won't be overlooked in
> the future.
>
>> ---
>> kernel/bpf/bpf_struct_ops.c | 157 +++++++++++++++++++-----------------
>> 1 file changed, 83 insertions(+), 74 deletions(-)
>>
>> diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
>> index fdc3e8705a3c..1662875e0ebe 100644
>> --- a/kernel/bpf/bpf_struct_ops.c
>> +++ b/kernel/bpf/bpf_struct_ops.c
>> @@ -110,102 +110,111 @@ const struct bpf_prog_ops
>> bpf_struct_ops_prog_ops = {
>> static const struct btf_type *module_type;
>> -void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
>> +static void bpf_struct_ops_init_one(struct bpf_struct_ops *st_ops,
>> + struct btf *btf,
>> + struct bpf_verifier_log *log)
>> {
>> - s32 type_id, value_id, module_id;
>> const struct btf_member *member;
>> - struct bpf_struct_ops *st_ops;
>> const struct btf_type *t;
>> + s32 type_id, value_id;
>> char value_name[128];
>> const char *mname;
>> - u32 i, j;
>> + int i;
>> - /* Ensure BTF type is emitted for "struct bpf_struct_ops_##_name" */
>> -#define BPF_STRUCT_OPS_TYPE(_name) BTF_TYPE_EMIT(struct
>> bpf_struct_ops_##_name);
>> -#include "bpf_struct_ops_types.h"
>> -#undef BPF_STRUCT_OPS_TYPE
>> + if (strlen(st_ops->name) + VALUE_PREFIX_LEN >=
>> + sizeof(value_name)) {
>> + pr_warn("struct_ops name %s is too long\n",
>> + st_ops->name);
>> + return;
>> + }
>> + sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
>> - module_id = btf_find_by_name_kind(btf, "module", BTF_KIND_STRUCT);
>> - if (module_id < 0) {
>> - pr_warn("Cannot find struct module in btf_vmlinux\n");
>> + value_id = btf_find_by_name_kind(btf, value_name,
>> + BTF_KIND_STRUCT);
>
> It needs to do some sanity checks on the value_type since this won't be
> statically enforced by bpf_struct_ops.c.
Do you mean to check if a value_type has refcnt, state and data field?
>
> [ ... ]
>
>> +void bpf_struct_ops_init(struct btf *btf, struct bpf_verifier_log *log)
>> +{
>> + struct bpf_struct_ops *st_ops;
>> + s32 module_id;
>> + u32 i;
>> - if (__btf_member_bitfield_size(t, member)) {
>> - pr_warn("bit field member %s in struct %s is not
>> supported\n",
>> - mname, st_ops->name);
>> - break;
>> - }
>> + /* Ensure BTF type is emitted for "struct bpf_struct_ops_##_name" */
>> +#define BPF_STRUCT_OPS_TYPE(_name) BTF_TYPE_EMIT(struct
>> bpf_struct_ops_##_name);
>> +#include "bpf_struct_ops_types.h"
>> +#undef BPF_STRUCT_OPS_TYPE
>
> Can this static way of defining struct_ops be removed? bpf_tcp_ca should
> be able to use the register_bpf_struct_ops() introduced in patch 2.
It sounds good for me.
>
> For the future subsystem supporting struct_ops, the subsystem could be
> compiled as a kernel module or as a built-in. register_bpf_struct_ops()
> should work for both.
>
next prev parent reply other threads:[~2023-09-16 1:35 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-13 6:14 [RFC bpf-next v2 0/9] Registrating struct_ops types from modules thinker.li
2023-09-13 6:14 ` [RFC bpf-next v2 1/9] bpf: refactory struct_ops type initialization to a function thinker.li
2023-09-15 22:43 ` Martin KaFai Lau
2023-09-16 1:35 ` Kui-Feng Lee [this message]
2023-09-13 6:14 ` [RFC bpf-next v2 2/9] bpf: add register and unregister functions for struct_ops thinker.li
2023-09-16 0:05 ` Martin KaFai Lau
2023-09-16 1:14 ` Kui-Feng Lee
2023-09-18 18:47 ` Martin KaFai Lau
2023-09-18 20:40 ` Kui-Feng Lee
2023-09-13 6:14 ` [RFC bpf-next v2 3/9] bpf: attach a module BTF to a bpf_struct_ops thinker.li
2023-09-13 6:14 ` [RFC bpf-next v2 4/9] bpf: use attached BTF to find correct type info of struct_ops progs thinker.li
2023-09-13 6:14 ` [RFC bpf-next v2 5/9] bpf: hold module for bpf_struct_ops_map thinker.li
2023-09-13 6:14 ` [RFC bpf-next v2 6/9] libbpf: Find correct module BTFs for struct_ops maps and progs thinker.li
2023-09-13 6:14 ` [RFC bpf-next v2 7/9] bpf: export btf_ctx_access to modules thinker.li
2023-09-13 6:14 ` [RFC bpf-next v2 8/9] selftests/bpf: test case for register_bpf_struct_ops() thinker.li
2023-09-13 6:14 ` [RFC bpf-next v2 9/9] Comments and debug thinker.li
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