[PATCH v2 hmm 10/11] mm/hmm: Do not use list*_rcu() for hmm->ranges

[John Hubbard]

On 6/6/19 11:44 AM, Jason Gunthorpe wrote:
> From: Jason Gunthorpe <jgg at mellanox.com>
> 
> This list is always read and written while holding hmm->lock so there is
> no need for the confusing _rcu annotations.
> 
> Signed-off-by: Jason Gunthorpe <jgg at mellanox.com>
> Reviewed-by: Jérôme Glisse <jglisse at redhat.com>
> ---
>  mm/hmm.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/hmm.c b/mm/hmm.c
> index c2fecb3ecb11e1..709d138dd49027 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -911,7 +911,7 @@ int hmm_range_register(struct hmm_range *range,
>  	mutex_lock(&hmm->lock);
>  
>  	range->hmm = hmm;
> -	list_add_rcu(&range->list, &hmm->ranges);
> +	list_add(&range->list, &hmm->ranges);
>  
>  	/*
>  	 * If there are any concurrent notifiers we have to wait for them for
> @@ -941,7 +941,7 @@ void hmm_range_unregister(struct hmm_range *range)
>  		return;
>  
>  	mutex_lock(&hmm->lock);
> -	list_del_rcu(&range->list);
> +	list_del(&range->list);
>  	mutex_unlock(&hmm->lock);
>  
>  	/* Drop reference taken by hmm_range_register() */
> 

Good point. I'd overlooked this many times.

    Reviewed-by: John Hubbard <jhubbard at nvidia.com>


thanks,
-- 
John Hubbard
NVIDIA