Messages in this thread | | | Date | Wed, 25 Mar 2015 07:30:18 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 1/3] rculist: Fix list_entry_rcu to read ptr with rcu_dereference_raw |
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On Tue, Mar 24, 2015 at 11:31:38AM +0100, Patrick Marlier wrote: > Change to read effectively ptr with rcu_dereference_raw and not the > __ptr variable on the stack. > > Signed-off-by: Patrick Marlier <patrick.marlier@gmail.com>
Avoiding an extra load could be worthwhile in a number of situations, agreed.
However, won't this change cause sparse to complain if invoked on a non-RCU-protected pointer? The ability to use list-RCU API members on both RCU and non-RCU pointers was one of the points of the previous commit, right?
Thanx, Paul
> --- > include/linux/rculist.h | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/include/linux/rculist.h b/include/linux/rculist.h > index a18b16f..9d9baea 100644 > --- a/include/linux/rculist.h > +++ b/include/linux/rculist.h > @@ -247,10 +247,7 @@ static inline void list_splice_init_rcu(struct > list_head *list, > * primitives such as list_add_rcu() as long as it's guarded by > rcu_read_lock(). > */ > #define list_entry_rcu(ptr, type, member) \ > -({ \ > - typeof(*ptr) __rcu *__ptr = (typeof(*ptr) __rcu __force *)ptr; \ > - container_of((typeof(ptr))rcu_dereference_raw(__ptr), type, member); \ > -}) > + container_of((typeof(ptr))rcu_dereference_raw(ptr), type, member) > > /** > * Where are list_empty_rcu() and list_first_entry_rcu()? > -- > 2.1.0 >
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