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Date: Wed, 29 Aug 2007 13:33:30 -0500
From: jschopp <jschopp@austin.ibm.com>
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To: Joachim Fenkes <fenkes@de.ibm.com>
Subject: Re: [PATCH 2.6.23] ibmebus: Prevent bus_id collisions
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Cc: Thomas Klein <tklein@de.ibm.com>, Jan-Bernd Themann <themann@de.ibm.com>,
	Paul Mackerras <pmac@au1.ibm.com>, LKML <linux-kernel@vger.kernel.org>,
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	Christoph Raisch <raisch@de.ibm.com>,
	Paul Mackerras <paulus@samba.org>, Nathan Lynch <ntl@pobox.com>,
	Stefan Roscher <stefan.roscher@de.ibm.com>
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> +	len = strlen(dn->full_name + 1);
> +	bus_len = min(len, BUS_ID_SIZE - 1);
> +	memcpy(dev->ofdev.dev.bus_id, dn->full_name + 1
> +	       + (len - bus_len), bus_len);
> +	for (i = 0; i < bus_len; i++)
> +		if (dev->ofdev.dev.bus_id[i] == '/')
> +			dev->ofdev.dev.bus_id[i] = '_';
>  
>  	/* Register with generic device framework. */
>  	if (ibmebus_register_device_common(dev, dn->name) != 0) {

What happens when the full name is > 31 characters?  It looks to me that it 
will be truncated, which takes away the uniqueness guarantee.

There must be an individual property that is guaranteed to be unique and 
less than 32 characters.  How about "ibm,my-drc-index"?  That looks like a 
good candidate.