Re: [PATCH tip/core/rcu 07/13] rcu: Move preemption disabling out of __srcu_read_lock()

[Paul E. McKenney]

On Tue, Oct 06, 2015 at 10:07:25PM +0200, Peter Zijlstra wrote:
> On Tue, Oct 06, 2015 at 09:13:42AM -0700, Paul E. McKenney wrote:
> > Currently, __srcu_read_lock() cannot be invoked from restricted
> > environments because it contains calls to preempt_disable() and
> > preempt_enable(), both of which can invoke lockdep, which is a bad
> > idea in some restricted execution modes.  This commit therefore moves
> > the preempt_disable() and preempt_enable() from __srcu_read_lock()
> > to srcu_read_lock().  It also inserts the preempt_disable() and
> > preempt_enable() around the call to __srcu_read_lock() in do_exit().
> 
> Did you not simply want to use: preempt_disable_notrace() ?

I believe that tracing the preempt_disable() in srcu_read_lock() and
srcu_read_unlock() is actually a good thing.  Or am I missing your
point?

							Thanx, Paul

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