[PATCH] Add PTHREAD_MUTEX_NORMAL_INT

[Carlos O'Donell]

On 06/24/2013 04:31 PM, Andi Kleen wrote:
> On Mon, Jun 24, 2013 at 04:25:52PM -0400, Carlos O'Donell wrote:
>> On 06/24/2013 04:17 PM, Andi Kleen wrote:
>>> From: Andi Kleen <ak@linux.intel.com>
>>>
>>> Carlos asked for PTHREAD_MUTEX_NORMAL_INT to be added
>>> to make some of the internal macros be easier to understand.
>>> It is always identical to DEFAULT, as NORMAL only makes
>>> a difference for settype.
>>
>> Thanks for this.
>>
>> As it stands however, with pthread_mutexattr_gettype loosing 
>> the type originally entered by the user, we are going to have to
>> propagate the new type internally.
> 
> It will return DEFAULT|NO_ELISION, which is identical in behaviour
> to NORMAL
> 
> So if you do 
> 
> settype(&a, NORMAL);
> settype(&b, gettype(&a));
> 
> it will all work as expected. Even b will have all NORMAL semantics.
> 
> The only case that wouldn't work is someone explicitely rechecking
> the value returned by gettype(). Is that really a problem?

Yes it is a problem.

It would violate the expected semantics of the interface.

Cheers,
Carlos.