From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: Eduard Zingerman <eddyz87@gmail.com>
Cc: Ihor Solodrai <ihor.solodrai@linux.dev>,
Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>,
andrii@kernel.org, bpf@vger.kernel.org, ast@kernel.org,
daniel@iogearbox.net, mykolal@fb.com, kernel-team@meta.com
Subject: Re: [PATCH bpf-next 1/2] bpf: add bpf_dynptr_memset() kfunc
Date: Mon, 23 Jun 2025 14:38:34 -0700 [thread overview]
Message-ID: <CAEf4BzYZBMOexPSM9=utpn22W=XMsztiE_X9AxO9CSSb1yv7LA@mail.gmail.com> (raw)
In-Reply-To: <a64d331ff474e9896c7d6c071e027c34fc8c2966.camel@gmail.com>
On Thu, Jun 19, 2025 at 11:17 AM Eduard Zingerman <eddyz87@gmail.com> wrote:
>
> On Thu, 2025-06-19 at 11:13 -0700, Eduard Zingerman wrote:
>
> [...]
>
> > Also, what's the plan if you'd like to memset only a fragment of the
> > memory pointed-to by dynptr?
>
> Oh, I see, there is bpf_dynptr_adjust(), sorry for the noise.
>
Even though we do have bpf_dynptr_adjust() for maximum generality and
flexibility, for most dynptr-based APIs we try to pass also additional
offset into dynptr to avoid unnecessary overhead. So it's not a bad
idea to add this to bpf_memset(), IMO.
bpf_memset(struct bpf_dynptr *dptr, u32 off, u8 val, u32 n) ?
a bit unfortunate that we have 3 integers that you need to be careful
to not swap accidentally, but even with just val and n you'd have to
be careful. For other APIs we normally have offset to follow dynptr
pointer, so hopefully this arrangement won't that surprising.
Thoughts?
next prev parent reply other threads:[~2025-06-23 21:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-18 22:33 [PATCH bpf-next 1/2] bpf: add bpf_dynptr_memset() kfunc Ihor Solodrai
2025-06-18 22:33 ` [PATCH bpf-next 2/2] selftests/bpf: add test cases for bpf_dynptr_memset() Ihor Solodrai
2025-06-18 23:44 ` [PATCH bpf-next 1/2] bpf: add bpf_dynptr_memset() kfunc Mykyta Yatsenko
2025-06-19 17:09 ` Ihor Solodrai
2025-06-19 17:19 ` Eduard Zingerman
2025-06-19 17:55 ` Ihor Solodrai
2025-06-19 17:57 ` Eduard Zingerman
2025-06-19 18:04 ` Ihor Solodrai
2025-06-19 18:13 ` Eduard Zingerman
2025-06-19 18:17 ` Eduard Zingerman
2025-06-23 21:38 ` Andrii Nakryiko [this message]
2025-06-23 21:45 ` Eduard Zingerman
2025-06-23 22:12 ` Andrii Nakryiko
2025-06-20 15:09 ` Mykyta Yatsenko
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