linux-kernel - RE: [greybus-dev] [PATCH] staging: greybus: fixed the coding style, labels should not be indented.

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Date:   Fri, 4 Jun 2021 08:13:57 +0000
From:   David Laight <David.Laight@...LAB.COM>
To:     'Alex Elder' <elder@...aro.org>,
        'Manikishan Ghantasala' <manikishanghantasala@...il.com>,
        Alex Elder <elder@...e.org>
CC:     Alex Elder <elder@...nel.org>,
        "greybus-dev@...ts.linaro.org" <greybus-dev@...ts.linaro.org>,
        "linux-staging@...ts.linux.dev" <linux-staging@...ts.linux.dev>,
        Johan Hovold <johan@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [greybus-dev] [PATCH] staging: greybus: fixed the coding style,
 labels should not be indented.

From: Alex Elder
> Sent: 03 June 2021 22:55
...
> Not necessarily, sizeof(bool) is implementation defined.
> And I thought you didn't think the size of the structure
> was very important...

It is 'implementation defined' but will be 32 bits on everything
except an old 32bit ARM ABI.

> In any case, I'm open to changing the type of these fields,
> and my preference would be bool rather than u8, because it
> is completely clear what it represents.

Yes, and it isn't at all clear what it actually means.
If the value of a bool memory location isn't 0 or 1
what does 'bool_a & bool_b' mean.
It might be 'undefined behaviour' - but that doesn't actually
exclude an ICBM hitting the coder's house!
I've seen very silly code generated (by an old gcc) for
simple statements like:
	bool_a |= bool_b;
Mostly because it didn't trust the values to be 0 or 1
and wanted to ensure the result was either 0 or 1.

If I use an integer type (as in traditional C) I know
what I'm getting and there are no unexpected comparisons
and conditionals.

	David

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