From owner-freebsd-current@FreeBSD.ORG  Thu Mar 10 06:32:42 2005
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To: Andrey Chernov <ache@nagual.pp.ru>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Thu, 10 Mar 2005 09:24:11 +0300."
             <20050310062410.GA27497@nagual.pp.ru> 
Date: Thu, 10 Mar 2005 07:32:39 +0100
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Sender: phk@critter.freebsd.dk
cc: current@FreeBSD.ORG
Subject: Re: [TEST(/review)] major/minor/devname fix 
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In message <20050310062410.GA27497@nagual.pp.ru>, Andrey Chernov writes:
>On Wed, Mar 09, 2005 at 10:40:18PM +0100, Poul-Henning Kamp wrote:
>> +dev_t
>> +dev2udev(struct cdev *x)
>> +{
>> +	if (x == NULL)
>> +		return (NODEV);
>> +	return (x->si_inode ^ devfs_random());
>> +}
>
>...
>
>> +	dp = devfs_itod(ud ^ devfs_random());
>
>
>Why you try to use randomization here instead of sequental ordering (or 
>reversing/shifting it)? In such small number of bits there is a big 
>probability of collisions may occurse.

There is no risk of collision, look at what devfs_random() does.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.