Subject: Re: [PATCH] ethtool.h: Add "structs are public" disclaimer comment

From: Jeff Garzik <[email-masked]>
Date: Sun, 14 Mar 2010 14:38:19 -0400

On 03/14/2010 01:50 PM, Ben Hutchings wrote:
> On Sun, 2010-03-14 at 09:17 -0700, Joe Perches wrote:
>> On Sat, 2010-03-13 at 18:11 -0800, David Miller wrote:
>>> For the millionth time, you cannot change these datastructures
>>> like this without breaking all existing userspace applications
>>> out there.
>>
>> Maybe this might help reduce the broken record repetitiveness.
>>
>> Signed-off-by: Joe Perches<[email-masked]>
>> ---
>> diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
>> index b33f316..9bd7583 100644
>> --- a/include/linux/ethtool.h
>> +++ b/include/linux/ethtool.h
>> @@ -10,6 +10,15 @@
>>    * Portions Copyright (C) Sun Microsystems 2008
>>    */
>>
>> +/*
>> + * Do not submit patches that change the public structs not guarded by
>> + * #ifdef __KERNEL__ in this file.
>> + *
>> + * In case the use of __u8, __u16, __u32 and other reserved types don't
>> + * mean much to you, these structs are used by user-space applications
>> + * and must not be changed.
>> + */
>
> This comment is not quite correct: reserved fields may be replaced so
> long as the structure size and offsets of other fields stay the same.

I don't think we need this in every ABI-related header, though, do we?

	Jeff