Re: [tip:core/urgent] futex: Update woken requeued futex_q lock_ptr

[Darren Hart <dvhltc@us.ibm.com>]

Ingo Molnar wrote:
> * tip-bot for Darren Hart <dvhltc@us.ibm.com> wrote:
> 
>> @@ -1030,6 +1034,11 @@ void requeue_pi_wake_futex(struct futex_q *q, union futex_key *key)
>>  	WARN_ON(!q->rt_waiter);
>>  	q->rt_waiter = NULL;
>>  
>> +	q->lock_ptr = &hb->lock;
>> +#ifdef CONFIG_DEBUG_PI_LIST
>> +	q->list.plist.slock = &hb->lock;
>> +#endif
>> +
>>  	wake_up_state(q->task, TASK_NORMAL);
>>  }
>>  
> 
> -tip testing found a build error with v2 of the patch:
> 
> kernel/futex.c: In function ‘requeue_pi_wake_futex’:
> kernel/futex.c:1039: error: ‘struct plist_head’ has no member named ‘slock’

Ingo,

I'm finding myself confused by the tip branches.  I was going to prepare 
you a "mainline" version of this patch, but tip/core-for-linus-2 doesn't 
have the original requeue_pi support in futex.c, while tag v2.6.31-rc5 
does have that support.

I'll prepare a patch against v2.6.31-rc5, but can you explain how you 
would prefer for people to send patches that are needed in both mainline 
and rt, but have slightly different implementations?

-- 
Darren Hart
IBM Linux Technology Center
Real-Time Linux Team