netdev - Re: [PATCH net-next v9 03/10] lib: packing: add pack_fields() and unpack

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Message-ID: <20241210105952.xbh7gnoaxseni66q@skbuf>
Date: Tue, 10 Dec 2024 12:59:52 +0200
From: Vladimir Oltean <vladimir.oltean@....com>
To: Jacob Keller <jacob.e.keller@...el.com>
Cc: Jakub Kicinski <kuba@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>,
	Tony Nguyen <anthony.l.nguyen@...el.com>,
	Przemek Kitszel <przemyslaw.kitszel@...el.com>,
	Masahiro Yamada <masahiroy@...nel.org>,
	netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next v9 03/10] lib: packing: add pack_fields() and
 unpack_fields()

On Mon, Dec 09, 2024 at 03:05:54PM -0800, Jacob Keller wrote:
> On 12/9/2024 2:18 PM, Jakub Kicinski wrote:
> > On Wed, 04 Dec 2024 17:22:49 -0800 Jacob Keller wrote:
> >> +/* Small packed field. Use with bit offsets < 256, buffers < 32B and
> >> + * unpacked structures < 256B.
> >> + */
> >> +struct packed_field_s {
> >> +	GEN_PACKED_FIELD_MEMBERS(u8);
> >> +};
> >> +
> >> +/* Medium packed field. Use with bit offsets < 65536, buffers < 8KB and
> >> + * unpacked structures < 64KB.
> >> + */
> >> +struct packed_field_m {
> >> +	GEN_PACKED_FIELD_MEMBERS(u16);
> >> +};
> > 
> > Random thought - would it be more intuitive to use the same size
> > suffixes as readX() / writeX()? b = byte, w = u16, l = u32, q = 64? 
> > If you're immediate reaction isn't "of course!" -- ignore me.
> 
> Its fine with me, but Vladimir was the one to change them from numbers
> (packed_field_8 to packed_field_s and packed_field_16 to packed_field_m).

That was to avoid confusion with the numbers in CHECK_PACKED_FIELDS_8(),
which meant something completely different (array length).

> @Vladimir, thoughts on using the byte/word suffixes over "small/medium"?
> 
> I'll work on preparing v10 with the git ignore fix, but will wait a bit
> before sending to get feedback here.

If you both think it is more intuitive to have struct packed_field_b,
packed_field_w etc, then so be it, it's just a name. I'm not too
attached to the current scheme either, and I do agree that "small" and
"medium" have burger connotations :(