Re: [PATCH] unshare: Cleanup up the sys_unshare interface before we are committed.

[Janak Desai <janak@us.ibm.com>]

Andrew Morton wrote:

>ebiederm@xmission.com (Eric W. Biederman) wrote:
>  
>
>>Since we have not crossed the magic 2.6.16 line can we please
>> include this patch.  My apologies for catching this so late in the
>> cycle.
>>
>> - Error if we are passed any flags we don't expect.
>>
>>   This preserves forward compatibility so programs that use new flags that
>>   run on old kernels will fail instead of silently doing the wrong thing.
>>    
>>
>
>Makes sense.
>
>  
>
>> - Use separate defines from sys_clone.
>>
>>   sys_unshare can't implement half of the clone flags under any circumstances
>>   and those that it does implement have subtlely different semantics than
>>   the clone flags.  Using a different set of flags sets the
>>   expectation that things will be different.
>>    
>>
>
>iirc there was some discussion about this and it was explicitly decided to
>keep the CLONE flags.
>
>Maybe Janak or Linus can comment?
>
>  
>
In the two prior discussions on this, the disagreement was on how much 
confusion
(if any) the use of CLONE_* flags would generate. I personally did not 
think that
it was confusing enough to add new flags, with the same values as CLONE_*
flags, in the kernel. Linus's last email (3/1/06) on the subject seemed 
to lean in that
direction as well. That's why I didn't take any action on it.

-Janak