[PATCH v6] um: Enable preemption in UML

[Richard Weinberger]

----- Ursprüngliche Mail -----
> Von: "Johannes Berg" <johannes at sipsolutions.net>
>> -	mmap_read_lock(mm);
>> +	/* We use a RCU lock instead of a mm lock, because
>> +	 * this can be invoked out of critical/atomic sections
>> +	 * and that does not agree with the sleepable semantics
>> +	 * of the standard semaphore based mm lock.
>> +	 */
>> +	rcu_read_lock();
> 
> Yeah I guess ... Seems like a very mechanical description of what's
> going on, rather than a description of why this is correct (which
> assumes no preempt and no SMP)?

Is the VMA list actually RCU aware?
On UML we might get away with that, but I agree with Johannes, this needs a more
detailed explanation.

Thanks,
//richard