Re: [PATCH] list_lru: don't call list_lru_from_kmem if the list_head is empty

[Vladimir Davydov <vdavydov@parallels.com>]

On Wed, Aug 19, 2015 at 10:05:40AM -0400, Jeff Layton wrote:
> If the list_head is empty then we'll have called list_lru_from_kmem
> for nothing. Move that call inside of the list_empty if block.
> 
> Cc: Vladimir Davydov <vdavydov@parallels.com>
> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>

Reviewed-by: Vladimir Davydov <vdavydov@parallels.com>

> ---
>  mm/list_lru.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/list_lru.c b/mm/list_lru.c
> index 909eca2c820e..e1da19fac1b3 100644
> --- a/mm/list_lru.c
> +++ b/mm/list_lru.c
> @@ -99,8 +99,8 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item)
>  	struct list_lru_one *l;
>  
>  	spin_lock(&nlru->lock);
> -	l = list_lru_from_kmem(nlru, item);
>  	if (list_empty(item)) {
> +		l = list_lru_from_kmem(nlru, item);
>  		list_add_tail(item, &l->list);
>  		l->nr_items++;
>  		spin_unlock(&nlru->lock);
> @@ -118,8 +118,8 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item)
>  	struct list_lru_one *l;
>  
>  	spin_lock(&nlru->lock);
> -	l = list_lru_from_kmem(nlru, item);
>  	if (!list_empty(item)) {
> +		l = list_lru_from_kmem(nlru, item);
>  		list_del_init(item);
>  		l->nr_items--;
>  		spin_unlock(&nlru->lock);

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