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! - 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
