Re: [PATCH] docs: rcu: Make reader aware of rcu_dereference_protected

[Paul E. McKenney]

On Tue, Oct 09, 2018 at 09:01:59PM -0700, Joel Fernandes wrote:
> On Tue, Oct 09, 2018 at 08:09:06PM -0700, Paul E. McKenney wrote:
> > On Mon, Oct 08, 2018 at 06:33:41PM -0700, Joel Fernandes (Google) wrote:
> > > whatisRCU says rcu_dereference cannot be used outside of rcu read lock
> > > protected sections. Its better to mention rcu_dereference_protected when
> > > it says that, so that the new reader is aware of this API and is not led
> > > to believing that all RCU dereferences in all situations have to be
> > > protected by a rcu_read_lock() and rcu_read_unlock().
> > > 
> > > Cc: tytso@xxxxxxx
> > > Suggested-by: tytso@xxxxxxx
> > > Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
> > 
> > Good stuff!  I queued and pushed this with some wordsmithing.  Could
> > you please check for my having messed something up?
> 
> One small nit which the below diff should fix, but otherwise looks good to
> me, thanks!

Good catch!  I rolled the into the commit, thank you!

							Thanx, Paul

>  - Joel
> 
> ----8<----
> 
> diff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
> index 38044c978e54..093b85ad49eb 100644
> --- a/Documentation/RCU/whatisRCU.txt
> +++ b/Documentation/RCU/whatisRCU.txt
> @@ -297,7 +297,7 @@ rcu_dereference()
>  	protected by locks acquired by the update-side code.  This variant
>  	avoids the lockdep warning that would happen when using (for
>  	example) rcu_dereference() without rcu_read_lock() protection.
> -	Using rcu_dereference_protected() also have the advantage
> +	Using rcu_dereference_protected() also has the advantage
>  	of permitting compiler optimizations that rcu_dereference()
>  	must prohibit.	The rcu_dereference_protected() variant takes
>  	a lockdep expression to indicate which locks must be acquired
>