From: Martin KaFai Lau <martin.lau@linux.dev>
To: thinker.li@gmail.com
Cc: sinquersw@gmail.com, 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 2/9] bpf: add register and unregister functions for struct_ops.
Date: Fri, 15 Sep 2023 17:05:26 -0700 [thread overview]
Message-ID: <414e9f49-ad34-5282-6c05-882876440f34@linux.dev> (raw)
In-Reply-To: <20230913061449.1918219-3-thinker.li@gmail.com>
On 9/12/23 11:14 PM, thinker.li@gmail.com wrote:
> +int register_bpf_struct_ops(struct bpf_struct_ops_mod *mod)
> +{
> + struct bpf_struct_ops *st_ops = mod->st_ops;
> + struct bpf_verifier_log *log;
> + struct btf *btf;
> + int err;
> +
> + if (mod->st_ops == NULL ||
> + mod->owner == NULL)
> + return -EINVAL;
> +
> + log = kzalloc(sizeof(*log), GFP_KERNEL | __GFP_NOWARN);
> + if (!log) {
> + err = -ENOMEM;
> + goto errout;
> + }
> +
> + log->level = BPF_LOG_KERNEL;
> +
> + btf = btf_get_module_btf(mod->owner);
Where is btf_put called?
It is not stored anywhere in patch 2, so a bit confusing. I quickly looked at
the following patches but also don't see the bpf_put.
> + if (!btf) {
> + err = -EINVAL;
> + goto errout;
> + }
> +
> + bpf_struct_ops_init_one(st_ops, btf, log);
> + err = add_struct_ops(st_ops);
> +
> +errout:
> + kfree(log);
> +
> + return err;
> +}
> +EXPORT_SYMBOL(register_bpf_struct_ops);
> +
> +int unregister_bpf_struct_ops(struct bpf_struct_ops_mod *mod)
It is not clear to me why the subsystem needs to explicitly call
unregister_bpf_struct_ops(). Can it be done similar to the module kfunc support
(the kfunc_set_tab goes away with the btf)?
Related to this, does it need to maintain a global struct_ops array for all
kernel module? Can the struct_ops be maintained under its corresponding module
btf itself?
> +{
> + struct bpf_struct_ops *st_ops = mod->st_ops;
> + int err;
> +
> + err = remove_struct_ops(st_ops);
> + if (!err && st_ops->uninit)
> + err = st_ops->uninit();
> +
> + return err;
> +}
> +EXPORT_SYMBOL(unregister_bpf_struct_ops);
next prev parent reply other threads:[~2023-09-16 0:05 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
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 [this message]
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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