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From: Mina Almasry <almasrymina@google.com>
Date: Tue, 13 Feb 2024 12:01:38 -0800
Message-ID: <CAHS8izOJMEtC1a26yJGMzV9jsX9TtE2xWXzWQ6qSi4ynXnr2Wg@mail.gmail.com>
Subject: Re: [RFC PATCH net-next v5 05/14] netdev: netdevice devmem allocator
To: Pavel Begunkov <asml.silence@gmail.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>, Martin KaFai Lau <martin.lau@linux.dev>, 
	Song Liu <song@kernel.org>, Yonghong Song <yonghong.song@linux.dev>, 
	John Fastabend <john.fastabend@gmail.com>, KP Singh <kpsingh@kernel.org>, 
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>, 
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org, 
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	dri-devel@lists.freedesktop.org, "David S. Miller" <davem@davemloft.net>, 
	Eric Dumazet <edumazet@google.com>, Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>, 
	Jonathan Corbet <corbet@lwn.net>, Richard Henderson <richard.henderson@linaro.org>, 
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	Thomas Bogendoerfer <tsbogend@alpha.franken.de>, 
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	Andrii Nakryiko <andrii@kernel.org>, David Ahern <dsahern@kernel.org>, 
	Willem de Bruijn <willemdebruijn.kernel@gmail.com>, Shuah Khan <shuah@kernel.org>, 
	Sumit Semwal <sumit.semwal@linaro.org>, =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>, 
	David Wei <dw@davidwei.uk>, Jason Gunthorpe <jgg@ziepe.ca>, Yunsheng Lin <linyunsheng@huawei.com>, 
	Shailend Chand <shailend@google.com>, Harshitha Ramamurthy <hramamurthy@google.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>
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On Tue, Feb 13, 2024 at 5:24=E2=80=AFAM Pavel Begunkov <asml.silence@gmail.=
com> wrote:
>
> On 12/18/23 02:40, Mina Almasry wrote:
> > Implement netdev devmem allocator. The allocator takes a given struct
> > netdev_dmabuf_binding as input and allocates net_iov from that
> > binding.
> >
> > The allocation simply delegates to the binding's genpool for the
> > allocation logic and wraps the returned memory region in a net_iov
> > struct.
> >
> > Signed-off-by: Willem de Bruijn <willemb@google.com>
> > Signed-off-by: Kaiyuan Zhang <kaiyuanz@google.com>
> > Signed-off-by: Mina Almasry <almasrymina@google.com>
> >
> > ---
> >
> > v1:
> > - Rename devmem -> dmabuf (David).
> >
> > ---
> >   include/net/devmem.h | 12 ++++++++++++
> >   include/net/netmem.h | 26 ++++++++++++++++++++++++++
> >   net/core/dev.c       | 38 ++++++++++++++++++++++++++++++++++++++
> >   3 files changed, 76 insertions(+)
> >
> ...
> > diff --git a/include/net/netmem.h b/include/net/netmem.h
> > index 45eb42d9990b..7fce2efc8707 100644
> > --- a/include/net/netmem.h
> > +++ b/include/net/netmem.h
> > @@ -14,8 +14,34 @@
> >
> >   struct net_iov {
> >       struct dmabuf_genpool_chunk_owner *owner;
> > +     unsigned long dma_addr;
> >   };
> >
> > +static inline struct dmabuf_genpool_chunk_owner *
> > +net_iov_owner(const struct net_iov *niov)
> > +{
> > +     return niov->owner;
> > +}
> > +
> > +static inline unsigned int net_iov_idx(const struct net_iov *niov)
> > +{
> > +     return niov - net_iov_owner(niov)->niovs;
> > +}
> > +
> > +static inline dma_addr_t net_iov_dma_addr(const struct net_iov *niov)
> > +{
> > +     struct dmabuf_genpool_chunk_owner *owner =3D net_iov_owner(niov);
> > +
> > +     return owner->base_dma_addr +
> > +            ((dma_addr_t)net_iov_idx(niov) << PAGE_SHIFT);
>
> Looks like it should have been niov->dma_addr
>

Yes, indeed. Thanks for catching.

> > +}
> > +
> > +static inline struct netdev_dmabuf_binding *
> > +net_iov_binding(const struct net_iov *niov)
> > +{
> > +     return net_iov_owner(niov)->binding;
> > +}
> > +
> >   /* netmem */
> >
> >   struct netmem {
> ...
>
> --
> Pavel Begunkov


--=20
Thanks,
Mina