MIME-Version: 1.0
References: <20190416203620.539628-1-arnd@arndb.de> <CAF=yD-K89Z2ea_iakjfP98GnfU-yXts8LU4GW3Rr_etJ+r92pw@mail.gmail.com>
In-Reply-To: <CAF=yD-K89Z2ea_iakjfP98GnfU-yXts8LU4GW3Rr_etJ+r92pw@mail.gmail.com>
From:   Arnd Bergmann <arnd@arndb.de>
Date:   Wed, 17 Apr 2019 18:19:25 +0200
Message-ID: <CAK8P3a2z5QT7VooQPytx-C+Z_+kxzqmWmB8x-ow9PaApPuFY8g@mail.gmail.com>
Subject: Re: [PATCH net-next 1/3] net: rework SIOCGSTAMP ioctl handling
To:     Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Ralf Baechle <ralf@linux-mips.org>,
        Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Oliver Hartkopp <socketcan@hartkopp.net>,
        Marc Kleine-Budde <mkl@pengutronix.de>,
        Gerrit Renker <gerrit@erg.abdn.ac.uk>,
        Alexander Aring <alex.aring@gmail.com>,
        Stefan Schmidt <stefan@datenfreihafen.org>,
        Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        Vlad Yasevich <vyasevich@gmail.com>,
        Neil Horman <nhorman@tuxdriver.com>,
        Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
        Andrew Hendry <andrew.hendry@gmail.com>,
        Eric Dumazet <edumazet@google.com>,
        Willem de Bruijn <willemb@google.com>,
        Deepa Dinamani <deepa.kernel@gmail.com>,
        Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, linux-hams@vger.kernel.org,
        Bluez mailing list <linux-bluetooth@vger.kernel.org>,
        linux-can@vger.kernel.org, dccp@vger.kernel.org,
        linux-wpan@vger.kernel.org, linux-sctp@vger.kernel.org,
        linux-x25@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Sender: linux-bluetooth-owner@vger.kernel.org
Precedence: bulk

On Wed, Apr 17, 2019 at 4:46 PM Willem de Bruijn
<willemdebruijn.kernel@gmail.com> wrote:
> On Tue, Apr 16, 2019 at 4:38 PM Arnd Bergmann <arnd@arndb.de> wrote:
> > The SIOCGSTAMP/SIOCGSTAMPNS ioctl commands are implemented by many
> > socket protocol handlers, and all of those end up calling the same
> > sock_get_timestamp()/sock_get_timestampns() helper functions, which
> > results in a lot of duplicate code.
> >
> > With the introduction of 64-bit time_t on 32-bit architectures, this
> > gets worse, as we then need four different ioctl commands in each
> > socket protocol implementation.
> >
> > To simplify that, let's add a new .gettstamp() operation in
> > struct proto_ops, and move ioctl implementation into the common
> > sock_ioctl()/compat_sock_ioctl_trans() functions that these all go
> > through.
> >
> > We can reuse the sock_get_timestamp() implementation, but generalize
> > it so it can deal with both native and compat mode, as well as
> > timeval and timespec structures.
> >
> > Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
> > Link: https://lore.kernel.org/lkml/CAK8P3a038aDQQotzua_QtKGhq8O9n+rdiz2=WDCp82ys8eUT+A@mail.gmail.com/
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > ---
> > v2: reworked to not break sparc64 support
>
> From the discussion of v1 I thought you planned to unconditionally
> call sock_gettstamp() for all protocols, avoiding the need to plumb in
> all these new callbacks?
>
> That is more concise, though this closer to the existing behavior. So,
> fine either way.

Thanks for the reminder. I have definitely waited too long before revisiting
this series, and only had a vague recollection of that discussion but could
not find it in the logs (found it now, and the Link I quoted...).

I would prefer to get this series into the coming merge window, and
probably don't have time to rework it completely by then, so I hope
the current version is ok.

I also found your comment on lock_sock(), which could be easily
added inside of sock_gettstamp() if you think we should have that.
There is one more issue I just noticed (I dropped the necessary
sock_read_timestamp()), so I have to repost the series anyway
to fix that.

       Arnd