Re: [PATCH v2 3/3] treewide: use get_random_u32_between() when possible

From: "Theodore Ts'o" <tytso@mit.edu>
To: Kees Cook <kees@kernel.org>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>,
	"Kees Cook" <keescook@chromium.org>,
	linux-kernel@vger.kernel.org, patches@lists.linux.dev,
	"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
	"Jakub Kicinski" <kuba@kernel.org>,
	"Russell King" <linux@armlinux.org.uk>,
	"Catalin Marinas" <catalin.marinas@arm.com>,
	"Thomas Bogendoerfer" <tsbogend@alpha.franken.de>,
	"Heiko Carstens" <hca@linux.ibm.com>,
	"Herbert Xu" <herbert@gondor.apana.org.au>,
	"Christoph Böhmwalder" <christoph.boehmwalder@linbit.com>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Jason Gunthorpe" <jgg@nvidia.com>,
	"Sakari Ailus" <sakari.ailus@linux.intel.com>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	"Andreas Dilger" <adilger.kernel@dilger.ca>,
	"Jaegeuk Kim" <jaegeuk@kernel.org>,
	"Richard Weinberger" <richard@nod.at>,
	"Darrick J . Wong" <djwong@kernel.org>,
	"SeongJae Park" <sj@kernel.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
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Subject: Re: [PATCH v2 3/3] treewide: use get_random_u32_between() when possible
Date: Thu, 17 Nov 2022 10:42:37 -0500	[thread overview]
Message-ID: <Y3ZWbcoGOdFjlPhS@mit.edu> (raw)
In-Reply-To: <0EE39896-C7B6-4CB6-87D5-22AA787740A9@kernel.org>

On Wed, Nov 16, 2022 at 04:47:27PM -0800, Kees Cook wrote:
> >> > - between
> >> > - ranged
> >> > - spanning
> >> > 
> >> > https://www.thefreedictionary.com/List-of-prepositions.htm
> >> > - amid
> >> > 
> >> > Sigh, names.
> >> 
> >> I think "inclusive" is best.
> >
> >I find it not very descriptive of what the function does. Is there one
> >you like second best? Or are you convinced they're all much much much
> >worse than "inclusive" that they shouldn't be considered?
> 
> Right, I don't think any are sufficiently descriptive. "Incluisve"
> with two arguments seems unambiguous and complete to me. :)

The problem with "between", "ranged", "spanning" is that they don't
tell the reader whether we're dealing with an "open interval" or a
"closed interval".  They are just different ways of saying that it's a
range between, say, 0 and 20.  But it doesn't tell you whether it
includes 0 or 20 or not.

The only way I can see for making it ambiguous is either to use the
terminology "closed interval" or "inclusive".  And "open" and "closed"
can have other meanings, so get_random_u32_inclusive() is going to be
less confusing than get_random_u32_closed().

Cheers,

					- Ted