From: Christoph Hellwig <hch@infradead.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Christoph Hellwig <hch@infradead.org>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Jiri Pirko <jiri@mellanox.com>,
Taehee Yoo <ap420073@gmail.com>,
Eric Dumazet <edumazet@google.com>,
Alexei Starovoitov <ast@kernel.org>, Andrew Lunn <andrew@lunn.ch>,
Jens Axboe <axboe@kernel.dk>, Networking <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] dev_ioctl: split out SIOC?IFMAP ioctls
Date: Tue, 29 Sep 2020 18:52:55 +0100 [thread overview]
Message-ID: <20200929175255.GA2330@infradead.org> (raw)
In-Reply-To: <CAK8P3a0ht1c34K+4k3XxGvWA9cxWJSMNzQR2iYMcm98guMsj1A@mail.gmail.com>
On Fri, Sep 25, 2020 at 02:28:29PM +0200, Arnd Bergmann wrote:
> > > +++ b/include/uapi/linux/if.h
> > > @@ -247,7 +247,13 @@ struct ifreq {
> > > short ifru_flags;
> > > int ifru_ivalue;
> > > int ifru_mtu;
> > > +#ifndef __KERNEL__
> > > + /*
> > > + * ifru_map is rarely used but causes the incompatibility
> > > + * between native and compat mode.
> > > + */
> > > struct ifmap ifru_map;
> > > +#endif
> >
> > Do we need a way to verify that this never changes the struct size?
>
> Not sure which way you would want to check. The point of the patch
> is that it does change the struct size inside of the kernel but not
> in user space.
>
> Do you mean we should check that the (larger) user space size
> remains what it is for future changes, or that the (smaller)
> kernel size remains the same on all kernels, or maybe both?
I had something like:
BUILD_BUG_ON(sizeof(struct ifmap) >
sizeof(struct ifreq) - IFNAMSIZ);
plus a suitable comment in mind.
next prev parent reply other threads:[~2020-09-29 17:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-18 12:05 [PATCH 1/2] ethtool: improve compat ioctl handling Arnd Bergmann
2020-09-18 12:05 ` [PATCH 2/2] dev_ioctl: split out SIOC?IFMAP ioctls Arnd Bergmann
2020-09-19 5:48 ` Christoph Hellwig
2020-09-25 12:28 ` Arnd Bergmann
2020-09-29 17:52 ` Christoph Hellwig [this message]
2020-10-01 15:00 ` Arnd Bergmann
2020-09-19 5:43 ` [PATCH 1/2] ethtool: improve compat ioctl handling Christoph Hellwig
2020-09-19 23:40 ` David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200929175255.GA2330@infradead.org \
--to=hch@infradead.org \
--cc=andrew@lunn.ch \
--cc=ap420073@gmail.com \
--cc=arnd@arndb.de \
--cc=ast@kernel.org \
--cc=axboe@kernel.dk \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=jiri@mellanox.com \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).