From: Andrew Lunn <andrew@lunn.ch>
To: Shenwei Wang <shenwei.wang@nxp.com>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"imx@lists.linux.dev" <imx@lists.linux.dev>
Subject: Re: [EXT] Re: [PATCH v4 1/2] net: page_pool: export page_pool_stats definition
Date: Tue, 15 Nov 2022 18:43:05 +0100 [thread overview]
Message-ID: <Y3PPqVK1p+9vso8T@lunn.ch> (raw)
In-Reply-To: <PAXPR04MB9185EEE74B09159C18C0FBDD89049@PAXPR04MB9185.eurprd04.prod.outlook.com>
> > I agree the API is broken, but i think there is a better fix.
> >
> > There should be a stub of page_pool_get_stats() for when
> > CONFIG_PAGE_POOL_STATS is disabled.
> >
> > Nothing actually dereferences struct page_pool_stats when you have this stub.
> > So it might be enough to simply have
> >
> > struct page_pool_stats{
> > };
> >
>
> As the structure is open when the CONFIG_PAGE_POOL_STATS is enabled, you can not
> prevent a user to access its members. The empty stub will still have problems in this
> kind of situations.
The users, i.e. the driver, has no need to access its members. The
members can change, new ones can be added, and it will not cause a
problem, given the way this API is defined. Ideally, page_pool_stats
would of been an opaque cookie, but that is not how it was
implemented :-(
Andrew
next prev parent reply other threads:[~2022-11-15 17:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-15 15:57 [PATCH v4 0/2] net: fec: add xdp and page pool statistics Shenwei Wang
2022-11-15 15:57 ` [PATCH v4 1/2] net: page_pool: export page_pool_stats definition Shenwei Wang
2022-11-15 17:12 ` Andrew Lunn
2022-11-15 17:18 ` [EXT] " Shenwei Wang
2022-11-15 17:43 ` Andrew Lunn [this message]
2022-11-15 17:52 ` Shenwei Wang
2022-11-15 15:57 ` [PATCH v4 2/2] net: fec: add xdp and page pool statistics Shenwei Wang
2022-11-15 17:28 ` Andrew Lunn
2022-11-15 17:53 ` [EXT] " Shenwei Wang
2022-11-15 17:57 ` [PATCH v4 0/2] " Saeed Mahameed
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