linux-kernel - Re: [Intel-gfx] [PATCH 1/5] linux/minmax.h: add non-atomic version of xchg

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Message-ID: <Y7b38vH8lgsnCI/m@FVFF77S0Q05N>
Date:   Thu, 5 Jan 2023 16:16:50 +0000
From:   Mark Rutland <mark.rutland@....com>
To:     David Laight <David.Laight@...lab.com>,
        'Jani Nikula' <jani.nikula@...ux.intel.com>,
        Arnd Bergmann <arnd@...db.de>,
        "intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        'Andrzej Hajda' <andrzej.hajda@...el.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [Intel-gfx] [PATCH 1/5] linux/minmax.h: add non-atomic version
 of xchg

On Thu, Jan 05, 2023 at 03:57:25PM +0100, Daniel Vetter wrote:
> It's more fun, for the atomic functions which don't have the atomic_
> prefix in their names, the __ prefixed versions provide the non-atomic
> implementation.  This pattern was started with the long * bitops stuff for
> managing really big bitmasks.
> 
> And I really don't think it's a great function name scheme that we should
> proliferate.

FWIW I agree it's not great, but we're stuck between a rock and a bikeshed
w.r.t. better naming -- it's quite hard to clean that up becuase the atomic_*()
namespace is reserved for atomic_t (and mirrors atomic64_*() and
atomic_long_*()).

We could consider renaming atomic_t to atomic32_t and atomic_*() to
atomic32_*(), which'd free up the atomic_*() namespace for more genral usage
(e.g. allowing us to have atomic_xchg() and xhcg(), with the latter not being
atomic).

Thanks,
Mark.