On Fri, Mar 10, 2023 at 10:09:28AM -0800, Sreevani Sreejith wrote:
> From: Sreevani <ssreevani@xxxxxxxx>
>
> Summary: Document that provides an overview of libbpf features for BPF
> application development.
It seems like you ignore some of my reviews at [1]. Anyway, I repeat
them here, augmenting my new comments.
The patch description should have been "Document overview of libbpf,
including its features for developing BPF programs.".
> +######
> libbpf
> -======
> +######
Why did you add heading overline and change the heading character marker?
> +The following code snippet shows how to read the parent field of a kernel
> +``task_struct`` using BPF CO-RE and libbf. The basic helper to read a field in a
> +CO-RE relocatable manner is ``bpf_core_read(dst, sz, src)``, which will read
> +``sz`` bytes from the field referenced by ``src`` into the memory pointed to by
> +``dst``.
> +
> + .. code-block:: C
> + :emphasize-lines: 6
> +
> + //...
> + struct task_struct *task = (void *)bpf_get_current_task();
> + struct task_struct *parent_task;
> + int err;
> +
> + err = bpf_core_read(&parent_task, sizeof(void *), &task->parent);
> + if (err) {
> + /* handle error */
> + }
> +
> + /* parent_task contains the value of task->parent pointer */
You may want to also add :lineos: option or manually add line numbers
if you add :emphasize-lines: so that readers can see the line number
it refers to.
> +Also, find the libbpf API documentation `here
> +<https://libbpf.readthedocs.io/en/latest/api.html>`_
"See also `libbpf API documentation <link>`_".
> +
> +libbpf and Rust
> +===============
> +
> +If you are building BPF applications in Rust, it is recommended to use the
> +`Libbpf-rs <https://github.com/libbpf/libbpf-rs>`_ library instead of bindgen
> +bindings directly to libbpf. Libbpf-rs wraps libbpf functionality in
> +Rust-idiomatic interfaces and provides libbpf-cargo plugin to handle BPF code
> +compilation and skeleton generation. Using Libbpf-rs will make building user
> +space part of the BPF application easier. Note that the BPF program themselves
> +must still be written in plain C.
BPF apps are application that use BPF program, right? I thought that
despite there is libbpf-rs, I still have to develop BPF apps in C.
Thanks.
[1]: https://lore.kernel.org/linux-doc/ZAqzeQZLNMyaZOck@xxxxxxxxx/
--
An old man doll... just what I always wanted! - Clara
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