On Tue, Mar 24, 2020 at 03:36:34PM +0000, Will Deacon wrote:
> hlist_nulls_del() is used for non-RCU deletion of an 'hlist_nulls_node'
> and so we can safely poison the ->next pointer without having to worry
> about concurrent readers, just like we do for other non-RCU list
> deletion primitives
>
> Cc: Paul E. McKenney <paulmck@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Agreed, any code having difficulty with this change should use instead
hlist_nulls_del_rcu().
Reviewed-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> ---
> include/linux/list_nulls.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/include/linux/list_nulls.h b/include/linux/list_nulls.h
> index fd154ceb5b0d..48f33ae16381 100644
> --- a/include/linux/list_nulls.h
> +++ b/include/linux/list_nulls.h
> @@ -99,6 +99,7 @@ static inline void __hlist_nulls_del(struct hlist_nulls_node *n)
> static inline void hlist_nulls_del(struct hlist_nulls_node *n)
> {
> __hlist_nulls_del(n);
> + n->next = LIST_POISON1;
> n->pprev = LIST_POISON2;
> }
>
> --
> 2.20.1
>
