From: Jason Gunthorpe <jgg@nvidia.com>
To: Mina Almasry <almasrymina@google.com>
Cc: "Yunsheng Lin" <linyunsheng@huawei.com>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"Paolo Abeni" <pabeni@redhat.com>,
"Christian König" <christian.koenig@amd.com>,
"Shakeel Butt" <shakeelb@google.com>,
"Willem de Bruijn" <willemdebruijn.kernel@gmail.com>
Subject: Re: [RFC PATCH net-next v5 2/2] net: add netmem to skb_frag_t
Date: Mon, 15 Jan 2024 20:01:29 -0400 [thread overview]
Message-ID: <20240116000129.GX734935@nvidia.com> (raw)
In-Reply-To: <CAHS8izOnhtQGeQ-EFmYjZyZ0eW2LqO0Rrm73eAB2su=UA34yTw@mail.gmail.com>
On Mon, Jan 15, 2024 at 03:23:33PM -0800, Mina Almasry wrote:
> > > You did not answer my question that I asked here, and ignoring this
> > > question is preventing us from making any forward progress on this
> > > discussion. What do you expect or want skb_frag_page() to do when
> > > there is no page in the frag?
> >
> > I would expect it to do nothing.
>
> I don't understand. skb_frag_page() with an empty implementation just
> results in a compiler error as the function needs to return a page
> pointer. Do you actually expect skb_frag_page() to unconditionally
> cast frag->netmem to a page pointer? That was explained as
> unacceptable over and over again by Jason and Christian as it risks
> casting devmem to page; completely unacceptable and will get nacked.
> Do you have a suggestion of what skb_frag_page() should do that will
> not get nacked by mm?
WARN_ON and return NULL seems reasonable?
Jason
next prev parent reply other threads:[~2024-01-16 0:01 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-09 1:14 [RFC PATCH net-next v5 0/2] Abstract page from net stack Mina Almasry
2024-01-09 1:14 ` [RFC PATCH net-next v5 1/2] net: introduce abstraction for network memory Mina Almasry
2024-01-10 18:45 ` Shakeel Butt
2024-01-09 1:14 ` [RFC PATCH net-next v5 2/2] net: add netmem to skb_frag_t Mina Almasry
2024-01-11 12:44 ` Yunsheng Lin
2024-01-12 0:34 ` Mina Almasry
2024-01-12 11:51 ` Yunsheng Lin
2024-01-12 15:35 ` Mina Almasry
2024-01-15 9:37 ` Yunsheng Lin
2024-01-15 23:23 ` Mina Almasry
2024-01-16 0:01 ` Jason Gunthorpe [this message]
2024-01-16 11:04 ` Yunsheng Lin
2024-01-16 12:16 ` Jason Gunthorpe
2024-01-17 9:28 ` Yunsheng Lin
2024-01-17 18:00 ` Mina Almasry
2024-01-17 18:34 ` Mina Almasry
2024-01-17 18:54 ` Willem de Bruijn
2024-01-18 8:52 ` Yunsheng Lin
2024-01-18 13:56 ` Mina Almasry
2024-01-10 2:03 ` [RFC PATCH net-next v5 0/2] Abstract page from net stack Jakub Kicinski
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