Message-ID: <4C485A0C.7020500@redhat.com>
Date: Thu, 22 Jul 2010 16:47:40 +0200
From: Stefan Assmann <sassmann@redhat.com>
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To: Ben Hutchings <bhutchings@solarflare.com>
CC: David Miller <davem@davemloft.net>, abadea@ixiacom.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org, gospo@redhat.com,
        gregory.v.rose@intel.com, alexander.h.duyck@intel.com,
        leedom@chelsio.com, harald@redhat.com
Subject: Re: [PATCH net-next] sysfs: add attribute to indicate hw address
 assignment type
References: <4C458CB7.3030508@redhat.com>	<4C458F50.4070200@ixiacom.com>	 <4C4593DA.9040207@redhat.com>	 <20100720.131839.134093789.davem@davemloft.net>	 <4C46AB60.5060008@redhat.com>	 <1279720478.2089.3.camel@achroite.uk.solarflarecom.com>	 <4C483E8D.4080300@redhat.com> <1279807643.2104.1.camel@achroite.uk.solarflarecom.com>
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On 22.07.2010 16:07, Ben Hutchings wrote:
> On Thu, 2010-07-22 at 14:50 +0200, Stefan Assmann wrote:
>> On 21.07.2010 15:54, Ben Hutchings wrote:
>>> On Wed, 2010-07-21 at 10:10 +0200, Stefan Assmann wrote:
>>>> I put Alex' idea into code for further discussion, keeping the names
>>>> mentioned here until we agree on the scope of this attribute. When we
>>>> have settled I'll post a patch with proper patch description.
>>> [...]
>>>
>>> Just a little nitpick: I think it would be clearer to use a more
>>> specific term like 'address source' or 'address assignment type' rather
>>> than 'address type'.
>>
>> Here's a proposal for the final patch.
> 
> Looks good, but...
> 
> [...]
>>  /**
>> + * dev_hw_addr_random - Create random MAC and set device flag
>> + * @dev: pointer to net_device structure
>> + * @addr: Pointer to a six-byte array containing the Ethernet address
>> + *
>> + * Generate random MAC to be used by a device and set addr_assign_type
>> + * so the state can be read by sysfs and be used by udev.
>> + */
>> +static inline void dev_hw_addr_random(struct net_device *dev, u8 *hwaddr)
>> +{
>> +	dev->addr_assign_type |= NET_ADDR_RANDOM;
>> +	random_ether_addr(hwaddr);
>> +}
> [...]
> 
> ...why '|=' and not '='?

The intention is to use addr_assign_type as a bit field.

Okay it it might not make too much sense to 'steal' a random MAC
address but in case we add more types later it might get useful.

  Stefan
--
Stefan Assmann         | Red Hat GmbH
Software Engineer      | Otto-Hahn-Strasse 20, 85609 Dornach
                       | HR: Amtsgericht Muenchen HRB 153243
                       | GF: Brendan Lane, Charlie Peters,
sassmann at redhat.com |     Michael Cunningham, Charles Cachera
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