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From:   Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Date:   Wed, 17 Apr 2019 10:46:05 -0400
Message-ID: <CAF=yD-K89Z2ea_iakjfP98GnfU-yXts8LU4GW3Rr_etJ+r92pw@mail.gmail.com>
Subject: Re: [PATCH net-next 1/3] net: rework SIOCGSTAMP ioctl handling
To:     Arnd Bergmann <arnd@arndb.de>
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>,
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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.