From: Stanislav Fomichev <sdf@google.com>
To: Eric Dumazet <edumazet@google.com>
Cc: "Mina Almasry" <almasrymina@google.com>,
"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
"David Ahern" <dsahern@kernel.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org,
linaro-mm-sig@lists.linaro.org,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
"Arnd Bergmann" <arnd@arndb.de>, "Shuah Khan" <shuah@kernel.org>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian König" <christian.koenig@amd.com>,
"Shakeel Butt" <shakeelb@google.com>,
"Jeroen de Borst" <jeroendb@google.com>,
"Praveen Kaligineedi" <pkaligineedi@google.com>,
"Willem de Bruijn" <willemb@google.com>,
"Kaiyuan Zhang" <kaiyuanz@google.com>
Subject: Re: [RFC PATCH v3 09/12] net: add support for skbs with unreadable frags
Date: Tue, 7 Nov 2023 14:23:20 -0800 [thread overview]
Message-ID: <ZUq42Po1Pn-9QxrM@google.com> (raw)
In-Reply-To: <CANn89iJNR8bYYBO92=f5_2hFoTK8+giH11o-7NHURoahwvV11w@mail.gmail.com>
On 11/07, Eric Dumazet wrote:
> On Tue, Nov 7, 2023 at 10:05 PM Stanislav Fomichev <sdf@google.com> wrote:
>
> >
> > I don't understand. We require an elaborate setup to receive devmem cmsgs,
> > why would some random application receive those?
>
>
> A TCP socket can receive 'valid TCP packets' from many different sources,
> especially with BPF hooks...
>
> Think of a bonding setup, packets being mirrored by some switches or
> even from tc.
>
> Better double check than be sorry.
>
> We have not added a 5th component in the 4-tuple lookups, being "is
> this socket a devmem one".
>
> A mix of regular/devmem skb is supported.
Can we mark a socket as devmem-only? Do we have any use-case for those
hybrid setups? Or, let me put it that way: do we expect API callers
to handle both linear and non-linear cases correctly?
As a consumer of the previous versions of these apis internally,
I find all those corner cases confusing :-( Hence trying to understand
whether we can make it a bit more rigid and properly defined upstream.
But going back to that MSG_SOCK_DEVMEM flag. If the application is
supposed to handle both linear and devmem chucks, why do we need
this extra MSG_SOCK_DEVMEM opt-in to signal that it's able to process
it? From Mina's reply, it seemed like MSG_SOCK_DEVMEM is there to
protect random applications that get misrouted devmem skb. I don't
see how returning EFAULT helps in that case.
WARNING: multiple messages have this Message-ID (diff)
From: Stanislav Fomichev <sdf@google.com>
To: Eric Dumazet <edumazet@google.com>
Cc: "Kaiyuan Zhang" <kaiyuanz@google.com>,
dri-devel@lists.freedesktop.org, linux-kselftest@vger.kernel.org,
"Shuah Khan" <shuah@kernel.org>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Mina Almasry" <almasrymina@google.com>,
"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>,
"Jeroen de Borst" <jeroendb@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
linux-media@vger.kernel.org, linux-arch@vger.kernel.org,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"Arnd Bergmann" <arnd@arndb.de>,
linaro-mm-sig@lists.linaro.org,
"Shakeel Butt" <shakeelb@google.com>,
"Willem de Bruijn" <willemb@google.com>,
netdev@vger.kernel.org, "David Ahern" <dsahern@kernel.org>,
"Ilias Apalodimas" <ilias.apalodimas@linaro.org>,
linux-kernel@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
"Praveen Kaligineedi" <pkaligineedi@google.com>,
"Christian König" <christian.koenig@amd.com>
Subject: Re: [RFC PATCH v3 09/12] net: add support for skbs with unreadable frags
Date: Tue, 7 Nov 2023 14:23:20 -0800 [thread overview]
Message-ID: <ZUq42Po1Pn-9QxrM@google.com> (raw)
In-Reply-To: <CANn89iJNR8bYYBO92=f5_2hFoTK8+giH11o-7NHURoahwvV11w@mail.gmail.com>
On 11/07, Eric Dumazet wrote:
> On Tue, Nov 7, 2023 at 10:05 PM Stanislav Fomichev <sdf@google.com> wrote:
>
> >
> > I don't understand. We require an elaborate setup to receive devmem cmsgs,
> > why would some random application receive those?
>
>
> A TCP socket can receive 'valid TCP packets' from many different sources,
> especially with BPF hooks...
>
> Think of a bonding setup, packets being mirrored by some switches or
> even from tc.
>
> Better double check than be sorry.
>
> We have not added a 5th component in the 4-tuple lookups, being "is
> this socket a devmem one".
>
> A mix of regular/devmem skb is supported.
Can we mark a socket as devmem-only? Do we have any use-case for those
hybrid setups? Or, let me put it that way: do we expect API callers
to handle both linear and non-linear cases correctly?
As a consumer of the previous versions of these apis internally,
I find all those corner cases confusing :-( Hence trying to understand
whether we can make it a bit more rigid and properly defined upstream.
But going back to that MSG_SOCK_DEVMEM flag. If the application is
supposed to handle both linear and devmem chucks, why do we need
this extra MSG_SOCK_DEVMEM opt-in to signal that it's able to process
it? From Mina's reply, it seemed like MSG_SOCK_DEVMEM is there to
protect random applications that get misrouted devmem skb. I don't
see how returning EFAULT helps in that case.
next prev parent reply other threads:[~2023-11-07 22:23 UTC|newest]
Thread overview: 254+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-06 2:43 [RFC PATCH v3 00/12] Device Memory TCP Mina Almasry
2023-11-06 2:43 ` Mina Almasry
2023-11-06 2:44 ` [RFC PATCH v3 01/12] net: page_pool: factor out releasing DMA from releasing the page Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-06 2:44 ` [RFC PATCH v3 02/12] net: page_pool: create hooks for custom page providers Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-07 7:44 ` Yunsheng Lin
2023-11-07 7:44 ` Yunsheng Lin
2023-11-09 11:09 ` Paolo Abeni
2023-11-09 11:09 ` Paolo Abeni
2023-11-10 23:19 ` Jakub Kicinski
2023-11-10 23:19 ` Jakub Kicinski
2023-11-13 3:28 ` Mina Almasry
2023-11-13 3:28 ` Mina Almasry
2023-11-13 22:10 ` Jakub Kicinski
2023-11-13 22:10 ` Jakub Kicinski
2023-11-06 2:44 ` [RFC PATCH v3 03/12] net: netdev netlink api to bind dma-buf to a net device Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-10 23:16 ` Jakub Kicinski
2023-11-10 23:16 ` Jakub Kicinski
2023-11-06 2:44 ` [RFC PATCH v3 04/12] netdev: support binding dma-buf to netdevice Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-07 7:46 ` Yunsheng Lin
2023-11-07 7:46 ` Yunsheng Lin
2023-11-07 21:59 ` Mina Almasry
2023-11-07 21:59 ` Mina Almasry
2023-11-08 3:40 ` Yunsheng Lin
2023-11-08 3:40 ` Yunsheng Lin
2023-11-09 2:22 ` Mina Almasry
2023-11-09 2:22 ` Mina Almasry
2023-11-09 9:29 ` Yunsheng Lin
2023-11-09 9:29 ` Yunsheng Lin
2023-11-08 23:47 ` David Wei
2023-11-08 23:47 ` David Wei
2023-11-09 2:25 ` Mina Almasry
2023-11-09 2:25 ` Mina Almasry
2023-11-09 8:29 ` Paolo Abeni
2023-11-09 8:29 ` Paolo Abeni
2023-11-10 2:59 ` Mina Almasry
2023-11-10 2:59 ` Mina Almasry
2023-11-10 7:38 ` Yunsheng Lin
2023-11-10 7:38 ` Yunsheng Lin
2023-11-10 9:45 ` Mina Almasry
2023-11-10 9:45 ` Mina Almasry
2023-11-10 23:19 ` Jakub Kicinski
2023-11-10 23:19 ` Jakub Kicinski
2023-11-11 2:19 ` Mina Almasry
2023-11-11 2:19 ` Mina Almasry
2023-11-06 2:44 ` [RFC PATCH v3 05/12] netdev: netdevice devmem allocator Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-06 23:44 ` David Ahern
2023-11-06 23:44 ` David Ahern
2023-11-07 22:10 ` Mina Almasry
2023-11-07 22:10 ` Mina Almasry
2023-11-07 22:55 ` David Ahern
2023-11-07 22:55 ` David Ahern
2023-11-07 23:03 ` Mina Almasry
2023-11-07 23:03 ` Mina Almasry
2023-11-09 1:15 ` David Wei
2023-11-09 1:15 ` David Wei
2023-11-10 14:26 ` Pavel Begunkov
2023-11-10 14:26 ` Pavel Begunkov
2023-11-11 17:19 ` David Ahern
2023-11-11 17:19 ` David Ahern
2023-11-14 16:09 ` Pavel Begunkov
2023-11-14 16:09 ` Pavel Begunkov
2023-11-09 1:00 ` David Wei
2023-11-09 1:00 ` David Wei
2023-11-08 3:48 ` Yunsheng Lin
2023-11-08 3:48 ` Yunsheng Lin
2023-11-09 1:41 ` Mina Almasry
2023-11-09 1:41 ` Mina Almasry
2023-11-07 7:45 ` Yunsheng Lin
2023-11-07 7:45 ` Yunsheng Lin
2023-11-09 8:44 ` Paolo Abeni
2023-11-09 8:44 ` Paolo Abeni
2023-11-06 2:44 ` [RFC PATCH v3 06/12] memory-provider: dmabuf devmem memory provider Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-06 21:02 ` Stanislav Fomichev
2023-11-06 21:02 ` Stanislav Fomichev
2023-11-06 23:49 ` David Ahern
2023-11-06 23:49 ` David Ahern
2023-11-08 0:02 ` Mina Almasry
2023-11-08 0:02 ` Mina Almasry
2023-11-08 0:10 ` David Ahern
2023-11-08 0:10 ` David Ahern
2023-11-10 23:16 ` Jakub Kicinski
2023-11-10 23:16 ` Jakub Kicinski
2023-11-13 4:54 ` Mina Almasry
2023-11-13 4:54 ` Mina Almasry
2023-11-06 2:44 ` [RFC PATCH v3 07/12] page-pool: device memory support Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-07 8:00 ` Yunsheng Lin
2023-11-07 8:00 ` Yunsheng Lin
2023-11-07 21:56 ` Mina Almasry
2023-11-07 21:56 ` Mina Almasry
2023-11-08 10:56 ` Yunsheng Lin
2023-11-08 10:56 ` Yunsheng Lin
2023-11-09 3:20 ` Mina Almasry
2023-11-09 3:20 ` Mina Almasry
2023-11-09 9:30 ` Yunsheng Lin
2023-11-09 9:30 ` Yunsheng Lin
2023-11-09 12:20 ` Mina Almasry
2023-11-09 12:20 ` Mina Almasry
2023-11-09 13:23 ` Yunsheng Lin
2023-11-09 13:23 ` Yunsheng Lin
2023-11-09 14:23 ` Christian König
2023-11-09 9:01 ` Paolo Abeni
2023-11-09 9:01 ` Paolo Abeni
2023-11-06 2:44 ` [RFC PATCH v3 08/12] net: support non paged skb frags Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-07 9:00 ` Yunsheng Lin
2023-11-07 9:00 ` Yunsheng Lin
2023-11-07 21:19 ` Mina Almasry
2023-11-07 21:19 ` Mina Almasry
2023-11-08 11:25 ` Yunsheng Lin
2023-11-08 11:25 ` Yunsheng Lin
2023-11-09 9:14 ` Paolo Abeni
2023-11-09 9:14 ` Paolo Abeni
2023-11-10 4:06 ` Mina Almasry
2023-11-10 4:06 ` Mina Almasry
2023-11-10 23:19 ` Jakub Kicinski
2023-11-10 23:19 ` Jakub Kicinski
2023-11-13 6:05 ` Mina Almasry
2023-11-13 6:05 ` Mina Almasry
2023-11-13 22:17 ` Jakub Kicinski
2023-11-13 22:17 ` Jakub Kicinski
2023-11-06 2:44 ` [RFC PATCH v3 09/12] net: add support for skbs with unreadable frags Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-06 18:47 ` Stanislav Fomichev
2023-11-06 18:47 ` Stanislav Fomichev
2023-11-06 19:34 ` David Ahern
2023-11-06 19:34 ` David Ahern
2023-11-06 20:31 ` Mina Almasry
2023-11-06 20:31 ` Mina Almasry
2023-11-06 21:59 ` Stanislav Fomichev
2023-11-06 21:59 ` Stanislav Fomichev
2023-11-06 22:18 ` Mina Almasry
2023-11-06 22:18 ` Mina Almasry
2023-11-06 22:59 ` Stanislav Fomichev
2023-11-06 22:59 ` Stanislav Fomichev
2023-11-06 23:14 ` Kaiyuan Zhang
2023-11-06 23:27 ` Mina Almasry
2023-11-06 23:27 ` Mina Almasry
2023-11-06 23:55 ` Stanislav Fomichev
2023-11-06 23:55 ` Stanislav Fomichev
2023-11-07 0:07 ` Willem de Bruijn
2023-11-07 0:07 ` Willem de Bruijn
2023-11-07 0:14 ` Stanislav Fomichev
2023-11-07 0:14 ` Stanislav Fomichev
2023-11-07 0:59 ` Stanislav Fomichev
2023-11-07 0:59 ` Stanislav Fomichev
2023-11-07 2:23 ` Willem de Bruijn
2023-11-07 2:23 ` Willem de Bruijn
2023-11-07 17:44 ` Stanislav Fomichev
2023-11-07 17:44 ` Stanislav Fomichev
2023-11-07 17:57 ` Willem de Bruijn
2023-11-07 17:57 ` Willem de Bruijn
2023-11-07 18:14 ` Stanislav Fomichev
2023-11-07 18:14 ` Stanislav Fomichev
2023-11-07 0:20 ` Mina Almasry
2023-11-07 0:20 ` Mina Almasry
2023-11-07 1:06 ` Stanislav Fomichev
2023-11-07 1:06 ` Stanislav Fomichev
2023-11-07 19:53 ` Mina Almasry
2023-11-07 19:53 ` Mina Almasry
2023-11-07 21:05 ` Stanislav Fomichev
2023-11-07 21:05 ` Stanislav Fomichev
2023-11-07 21:17 ` Eric Dumazet
2023-11-07 21:17 ` Eric Dumazet
2023-11-07 22:23 ` Stanislav Fomichev [this message]
2023-11-07 22:23 ` Stanislav Fomichev
2023-11-10 23:17 ` Jakub Kicinski
2023-11-10 23:17 ` Jakub Kicinski
2023-11-10 23:19 ` Jakub Kicinski
2023-11-10 23:19 ` Jakub Kicinski
2023-11-07 1:09 ` David Ahern
2023-11-07 1:09 ` David Ahern
2023-11-06 23:37 ` David Ahern
2023-11-06 23:37 ` David Ahern
2023-11-07 0:03 ` Mina Almasry
2023-11-07 0:03 ` Mina Almasry
2023-11-06 20:56 ` Stanislav Fomichev
2023-11-06 20:56 ` Stanislav Fomichev
2023-11-07 0:16 ` David Ahern
2023-11-07 0:16 ` David Ahern
2023-11-07 0:23 ` Mina Almasry
2023-11-07 0:23 ` Mina Almasry
2023-11-08 14:43 ` David Laight
2023-11-08 14:43 ` David Laight
2023-11-06 2:44 ` [RFC PATCH v3 10/12] tcp: RX path for devmem TCP Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-06 18:44 ` Stanislav Fomichev
2023-11-06 18:44 ` Stanislav Fomichev
2023-11-06 19:29 ` Mina Almasry
2023-11-06 19:29 ` Mina Almasry
2023-11-06 21:14 ` Willem de Bruijn
2023-11-06 21:14 ` Willem de Bruijn
2023-11-06 22:34 ` Stanislav Fomichev
2023-11-06 22:34 ` Stanislav Fomichev
2023-11-06 22:55 ` Willem de Bruijn
2023-11-06 22:55 ` Willem de Bruijn
2023-11-06 23:32 ` Stanislav Fomichev
2023-11-06 23:32 ` Stanislav Fomichev
2023-11-06 23:55 ` David Ahern
2023-11-06 23:55 ` David Ahern
2023-11-07 0:02 ` Willem de Bruijn
2023-11-07 0:02 ` Willem de Bruijn
2023-11-07 23:55 ` Mina Almasry
2023-11-07 23:55 ` Mina Almasry
2023-11-08 0:01 ` David Ahern
2023-11-08 0:01 ` David Ahern
2023-11-09 2:39 ` Mina Almasry
2023-11-09 2:39 ` Mina Almasry
2023-11-09 16:07 ` Edward Cree
2023-11-09 16:07 ` Edward Cree
2023-12-08 20:12 ` Pavel Begunkov
2023-12-08 20:12 ` Pavel Begunkov
2023-11-09 11:05 ` Paolo Abeni
2023-11-09 11:05 ` Paolo Abeni
2023-11-10 23:16 ` Jakub Kicinski
2023-11-10 23:16 ` Jakub Kicinski
2023-12-08 20:28 ` Pavel Begunkov
2023-12-08 20:28 ` Pavel Begunkov
2023-12-08 20:09 ` Pavel Begunkov
2023-12-08 20:09 ` Pavel Begunkov
2023-11-06 21:17 ` Stanislav Fomichev
2023-11-06 21:17 ` Stanislav Fomichev
2023-11-08 15:36 ` Edward Cree
2023-11-08 15:36 ` Edward Cree
2023-11-09 10:52 ` Paolo Abeni
2023-11-09 10:52 ` Paolo Abeni
2023-11-10 23:19 ` Jakub Kicinski
2023-11-10 23:19 ` Jakub Kicinski
2023-11-06 2:44 ` [RFC PATCH v3 11/12] net: add SO_DEVMEM_DONTNEED setsockopt to release RX pages Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-06 2:44 ` [RFC PATCH v3 12/12] selftests: add ncdevmem, netcat for devmem TCP Mina Almasry
2023-11-06 2:44 ` Mina Almasry
2023-11-09 11:03 ` Paolo Abeni
2023-11-09 11:03 ` Paolo Abeni
2023-11-10 23:13 ` Jakub Kicinski
2023-11-10 23:13 ` Jakub Kicinski
2023-11-11 2:27 ` Mina Almasry
2023-11-11 2:27 ` Mina Almasry
2023-11-11 2:35 ` Jakub Kicinski
2023-11-11 2:35 ` Jakub Kicinski
2023-11-13 4:08 ` Mina Almasry
2023-11-13 4:08 ` Mina Almasry
2023-11-13 22:20 ` Jakub Kicinski
2023-11-13 22:20 ` Jakub Kicinski
2023-11-10 23:17 ` Jakub Kicinski
2023-11-10 23:17 ` Jakub Kicinski
2023-11-07 15:18 ` [RFC PATCH v3 00/12] Device Memory TCP David Ahern
2023-11-07 15:18 ` David Ahern
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