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Date: Fri, 16 Feb 2007 10:50:26 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: James Bottomley <James.Bottomley@SteelEye.com>
Cc: ricknu-0@student.ltu.se, linux-kernel@vger.kernel.org,
       linux-scsi@vger.kernel.org
Subject: Re: [PATCH] drivers/scsi/aic7xxx_old: Convert to generic
 boolean-values
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On Fri, 16 Feb 2007 12:42:27 -0600 James Bottomley <James.Bottomley@SteelEye.com> wrote:

> On Fri, 2007-02-16 at 10:34 -0800, Andrew Morton wrote:
> > On Fri, 16 Feb 2007 10:42:12 -0600 James Bottomley <James.Bottomley@SteelEye.com> wrote:
> > 
> > > On Mon, 2007-02-12 at 12:27 -0800, Andrew Morton wrote:
> > > > Given that we now have a standard kernel-wide, c99-friendly way of
> > > > expressing true and false, I'd suggest that this decision can be revisited.
> > > > 
> > > > Because a "true" is significantly more meaningful (and hence readable)
> > > > thing than a bare "1".
> > > 
> > > OK, I'm really not happy with doing this for three reasons:
> > > 
> > > 1. It's inviting huge amounts of driver churn changing bitfields to
> > > booleans
> > > 
> > > 2. I do find it to be a readability issue.  Like most driver writers,
> > > I'm used to register layouts, and those are simple bitfields, so I don't
> > > tend to think true and false, I think 1 and 0.
> > > 
> > > 3. Having a different, special, type for single bit bitfields (while
> > > still using u<n> for multi bit bitfields) is asking for confusion, and
> > > hence trouble at the driver level.
> > > 
> > 
> > Confused.  The patch changes TRUE to true and FALSE to false.  The code
> > wasn't using bitfields before and isn't using them afterwards.  I wouldn't
> > expect there to be any change in generated code.
> 
> Sorry, I was addressing the general idea of using booleans in drivers.
> 
> > All it's doing is replacing the driver's private TRUE/FALSE with the
> > kernel-wide ones.
> 
> I already addressed that one ... I prefer bare 0 and 1.  However, if the
> driver writer wants to use TRUE/FALSE, I won't specifically reject it.
> I really don't like the lower case true/false.
> 

Me no understand.

If you take the specific example of

void
ahd_set_syncrate(struct ahd_softc *ahd, struct ahd_devinfo *devinfo,
		 u_int period, u_int offset, u_int ppr_options,
		 u_int type, int paused)

then if is crufty, inappropriate and wrong that `paused' is a scalar type. 
It's just not true or sensible that the code is written so that `paused'
can take a value of seventy eight.  It _is_ a boolean.  It is a truth
value.  Declaring it as such in the source is all goodness.  Passing the
value `true' into calls to this function improve readability over passing
"1".

So I don't agree with (or understand) your objections.  But I can certainly
understand reluctance to merge a large-but-minor, do-nothing-much patch into
a large and not-very-maintained driver.
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