netdev - Re: [RFC PATCH net-next v6 09/15] memory-provider: dmabuf devmem memory provider

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b85b36bd-7082-47a5-bf46-50cff8eb60be@gmail.com>
Date: Wed, 6 Mar 2024 14:58:38 +0000
From: Pavel Begunkov <asml.silence@...il.com>
To: Mina Almasry <almasrymina@...gle.com>, David Wei <dw@...idwei.uk>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-doc@...r.kernel.org, linux-alpha@...r.kernel.org,
 linux-mips@...r.kernel.org, linux-parisc@...r.kernel.org,
 sparclinux@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
 linux-arch@...r.kernel.org, bpf@...r.kernel.org,
 linux-kselftest@...r.kernel.org, linux-media@...r.kernel.org,
 dri-devel@...ts.freedesktop.org, "David S. Miller" <davem@...emloft.net>,
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, Jonathan Corbet <corbet@....net>,
 Richard Henderson <richard.henderson@...aro.org>,
 Ivan Kokshaysky <ink@...assic.park.msu.ru>, Matt Turner
 <mattst88@...il.com>, Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
 "James E.J. Bottomley" <James.Bottomley@...senpartnership.com>,
 Helge Deller <deller@....de>, Andreas Larsson <andreas@...sler.com>,
 Jesper Dangaard Brouer <hawk@...nel.org>,
 Ilias Apalodimas <ilias.apalodimas@...aro.org>,
 Steven Rostedt <rostedt@...dmis.org>, Masami Hiramatsu
 <mhiramat@...nel.org>, Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
 Arnd Bergmann <arnd@...db.de>, Alexei Starovoitov <ast@...nel.org>,
 Daniel Borkmann <daniel@...earbox.net>, Andrii Nakryiko <andrii@...nel.org>,
 Martin KaFai Lau <martin.lau@...ux.dev>, Eduard Zingerman
 <eddyz87@...il.com>, Song Liu <song@...nel.org>,
 Yonghong Song <yonghong.song@...ux.dev>,
 John Fastabend <john.fastabend@...il.com>, KP Singh <kpsingh@...nel.org>,
 Stanislav Fomichev <sdf@...gle.com>, Hao Luo <haoluo@...gle.com>,
 Jiri Olsa <jolsa@...nel.org>, David Ahern <dsahern@...nel.org>,
 Willem de Bruijn <willemdebruijn.kernel@...il.com>,
 Shuah Khan <shuah@...nel.org>, Sumit Semwal <sumit.semwal@...aro.org>,
 Christian König <christian.koenig@....com>,
 Jason Gunthorpe <jgg@...pe.ca>, Yunsheng Lin <linyunsheng@...wei.com>,
 Shailend Chand <shailend@...gle.com>,
 Harshitha Ramamurthy <hramamurthy@...gle.com>,
 Jeroen de Borst <jeroendb@...gle.com>,
 Praveen Kaligineedi <pkaligineedi@...gle.com>,
 Willem de Bruijn <willemb@...gle.com>, Kaiyuan Zhang <kaiyuanz@...gle.com>
Subject: Re: [RFC PATCH net-next v6 09/15] memory-provider: dmabuf devmem
 memory provider

On 3/6/24 02:42, Mina Almasry wrote:
> On Tue, Mar 5, 2024 at 6:28 PM David Wei <dw@...idwei.uk> wrote:
>>
>> On 2024-03-04 18:01, Mina Almasry wrote:
>>> +     if (pool->p.queue)
>>> +             binding = READ_ONCE(pool->p.queue->binding);
>>> +
>>> +     if (binding) {
>>> +             pool->mp_ops = &dmabuf_devmem_ops;
>>> +             pool->mp_priv = binding;
>>> +     }
>>
>> This is specific to TCP devmem. For ZC Rx we will need something more
>> generic to let us pass our own memory provider backend down to the page
>> pool.
>>
>> What about storing ops and priv void ptr in struct netdev_rx_queue
>> instead? Then we can both use it.
> 
> Yes, this is dmabuf specific, I was thinking you'd define your own
> member of netdev_rx_queue, and then add something like this to
> page_pool_init:

That would be quite annoying, there are 3 expected users together
with huge pages, each would need a field and check all others are
disabled as you mentioned and so on. It should be cleaner to pass
a generic {pp_ops,pp_private} pair instead.

If header dependencies is a problem, you it can probably be

struct pp_provider_param {
	struct pp_ops ops;
	void *private;
};

# netdev_rx_queue.h

// definition is not included here
struct pp_provider_params;

struct netdev_rx_queue {
	...
	struct pp_provider_params *pp_params;
};

-- 
Pavel Begunkov