From: David Laight <david.laight.linux@gmail.com>
To: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: Yury Norov <yury.norov@gmail.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
Geert Uytterhoeven <geert+renesas@glider.be>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
Crt Mori <cmo@melexis.com>,
Richard Genoud <richard.genoud@bootlin.com>,
Luo Jie <quic_luoj@quicinc.com>,
Peter Zijlstra <peterz@infradead.org>,
Jakub Kicinski <kuba@kernel.org>,
netdev@vger.kernel.org, "David S . Miller" <davem@davemloft.net>,
Simon Horman <simon.horman@netronome.com>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
Andreas Noever <andreas.noever@gmail.com>,
Yehezkel Bernat <YehezkelShB@gmail.com>,
Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Subject: Re: [PATCH 3/9] bitmap: Use FIELD_PREP() in expansion of FIELD_PREP_WM16()
Date: Tue, 9 Dec 2025 18:54:52 +0000 [thread overview]
Message-ID: <20251209185452.707f4dbe@pumpkin> (raw)
In-Reply-To: <aThETSRch_okmCbe@smile.fi.intel.com>
On Tue, 9 Dec 2025 17:46:21 +0200
Andy Shevchenko <andriy.shevchenko@intel.com> wrote:
> On Tue, Dec 09, 2025 at 10:03:07AM +0000, david.laight.linux@gmail.com wrote:
>
> > Instead of directly expanding __BF_FIELD_CHECK() (which really ought
> > not be used outside bitfield) and open-coding the generation of the
> > masked value, just call FIELD_PREP() and add an extra check for
> > the mask being at most 16 bits.
>
> ...
>
> > +#define FIELD_PREP_WM16(mask, val) \
> > +({ \
> > + __auto_type _mask = mask; \
> > + u32 _val = FIELD_PREP(_mask, val); \
>
> > + BUILD_BUG_ON_MSG(_mask > 0xffffu, \
> > + "FIELD_PREP_WM16: mask too large"); \
>
> Can it be static_assert() instead?
No, they have to be 'integer constant expressions' not just
'compile time constants'.
Pretty useless for anything non-trivial.
David
>
> > + _val | (_mask << 16); \
> > +})
>
next prev parent reply other threads:[~2025-12-09 18:54 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-09 10:03 [PATCH 0/9] bitfield: tidy up bitfield.h david.laight.linux
2025-12-09 10:03 ` [PATCH 1/9] nfp: Call FIELD_PREP() in NFP_ETH_SET_BIT_CONFIG() wrapper david.laight.linux
2025-12-10 9:29 ` Jakub Kicinski
2025-12-10 10:04 ` David Laight
2025-12-09 10:03 ` [PATCH 2/9] thunderblot: Don't pass a bitfield to FIELD_GET david.laight.linux
2025-12-10 5:56 ` Mika Westerberg
2025-12-10 9:34 ` David Laight
2025-12-10 9:41 ` Mika Westerberg
2025-12-10 10:18 ` David Laight
2025-12-10 18:13 ` Yury Norov
2025-12-10 20:23 ` David Laight
2025-12-09 10:03 ` [PATCH 3/9] bitmap: Use FIELD_PREP() in expansion of FIELD_PREP_WM16() david.laight.linux
2025-12-09 15:46 ` Andy Shevchenko
2025-12-09 18:54 ` David Laight [this message]
2025-12-10 19:18 ` Nicolas Frattaroli
2025-12-10 20:59 ` David Laight
2025-12-11 12:50 ` Nicolas Frattaroli
2025-12-11 17:52 ` David Laight
2025-12-09 10:03 ` [PATCH 4/9] bitfield: Copy #define parameters to locals david.laight.linux
2025-12-09 15:51 ` Andy Shevchenko
2025-12-09 19:11 ` David Laight
2025-12-09 21:54 ` Andy Shevchenko
2025-12-10 18:45 ` Yury Norov
2025-12-09 10:03 ` [PATCH 5/9] bitfield: FIELD_MODIFY: Only do a single read/write on the target david.laight.linux
2025-12-09 10:03 ` [PATCH 6/9] bitfield: Update sanity checks david.laight.linux
2025-12-09 10:03 ` [PATCH 7/9] bitfield: Reduce indentation david.laight.linux
2025-12-09 10:03 ` [PATCH 8/9] bitfield: Add comment block for the host/fixed endian functions david.laight.linux
2025-12-09 15:53 ` Andy Shevchenko
2025-12-10 9:23 ` Jakub Kicinski
2025-12-10 10:08 ` David Laight
2025-12-11 5:26 ` Jakub Kicinski
2025-12-09 10:03 ` [PATCH 9/9] bitfield: Update comments for le/be functions david.laight.linux
2025-12-10 18:20 ` [PATCH 0/9] bitfield: tidy up bitfield.h Yury Norov
2025-12-10 22:40 ` David Laight
2025-12-11 10:51 ` David Laight
-- strict thread matches above, loose matches on Subject: below --
2025-12-08 22:42 david.laight.linux
2025-12-08 22:42 ` [PATCH 3/9] bitmap: Use FIELD_PREP() in expansion of FIELD_PREP_WM16() david.laight.linux
2025-12-09 0:54 ` Yury Norov
2025-12-09 9:56 ` David Laight
2025-12-11 18:53 ` David Laight
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