[PATCH 2/3] ath10k: Grab rcu_read_lock before the txqs spinlock.

Johannes Berg johannes at sipsolutions.net
Sun Sep 11 23:41:49 PDT 2016

> > > -	rcu_read_unlock();
> > >   	spin_unlock_bh(&ar->txqs_lock);
> > > +	rcu_read_unlock();
> > 
> > I'm no RCU expert but this isn't making any sense. Maybe it changes
> > timings on your kernel so that it hides the real problem?
> I'm not sure this fixed anything or not, it just seemed weird so I
> changed it.
> I was hoping someone that understood rcu locking would comment...

RCU is no "locking". The sooner you get over that notion, the better.

This therefore make no sense whatsoever.

In fact, you want to keep the RCU protected section *small*, so having
the spinlock inside hurts overall system performance.


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