From: Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>
To: Eduard Zingerman <eddyz87@gmail.com>,
Ihor Solodrai <ihor.solodrai@linux.dev>,
andrii@kernel.org
Cc: 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: Fri, 20 Jun 2025 16:09:40 +0100 [thread overview]
Message-ID: <4c236e03-f63e-413d-86dd-15288f4c61ee@gmail.com> (raw)
In-Reply-To: <7852f30ba177dc5b811bb0840ca0f301df2a8b58.camel@gmail.com>
On 6/19/25 18:19, Eduard Zingerman wrote:
> On Thu, 2025-06-19 at 10:09 -0700, Ihor Solodrai wrote:
>
> [...]
>
>> But then, does memset even make sense for xdp/skb buffers?
> Why not?
>
>> Maybe -ENOTSUPP is more appropriate?
>>
>> I'd appreciate any hints.
> I think Mykyta has kernel/trace/bpf_trace.c:__bpf_dynptr_copy_str() in mind.
>
Right, similarly to `__bpf_dynptr_copy` from bpf_trace.c: fast path if
destination has enough contiguous memory,
just call memset.
Slow path - use temp buffer, that you can memset once and then
__bpf_dynptr_write it in a loop. __bpf_dynptr_write
handles the trickiness of the non-contiguous buffers.
prev parent reply other threads:[~2025-06-20 15:09 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
2025-06-23 21:45 ` Eduard Zingerman
2025-06-23 22:12 ` Andrii Nakryiko
2025-06-20 15:09 ` Mykyta Yatsenko [this message]
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