Re: [PATCH -next] mm: zswap: use helper function put_z3fold_locked()

[Miaohe Lin <linmiaohe@huawei.com>]

On 2023/8/3 15:08, Ruan Jinjie wrote:
> This code is already duplicated six times, use helper function
> put_z3fold_locked() to release z3fold page instead of open code it
> to help improve code readability a bit. No functional change involved.
> 

There is one "if (kref_put(&zhdr->refcount, release_z3fold_page_locked_list))" left in z3fold_free().
It might be better to add another helper for it to make code more consistent? But no preference.

Thanks.

> Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
> ---
>  mm/z3fold.c | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/mm/z3fold.c b/mm/z3fold.c
> index e84de91ecccb..0b483de83d95 100644
> --- a/mm/z3fold.c
> +++ b/mm/z3fold.c
> @@ -480,6 +480,11 @@ static void release_z3fold_page_locked_list(struct kref *ref)
>  	__release_z3fold_page(zhdr, true);
>  }
>  
> +static inline int put_z3fold_locked(struct z3fold_header *zhdr)
> +{
> +	return kref_put(&zhdr->refcount, release_z3fold_page_locked);
> +}
> +
>  static void free_pages_work(struct work_struct *w)
>  {
>  	struct z3fold_pool *pool = container_of(w, struct z3fold_pool, work);
> @@ -666,7 +671,7 @@ static struct z3fold_header *compact_single_buddy(struct z3fold_header *zhdr)
>  	return new_zhdr;
>  
>  out_fail:
> -	if (new_zhdr && !kref_put(&new_zhdr->refcount, release_z3fold_page_locked)) {
> +	if (new_zhdr && !put_z3fold_locked(new_zhdr)) {
>  		add_to_unbuddied(pool, new_zhdr);
>  		z3fold_page_unlock(new_zhdr);
>  	}
> @@ -741,7 +746,7 @@ static void do_compact_page(struct z3fold_header *zhdr, bool locked)
>  	list_del_init(&zhdr->buddy);
>  	spin_unlock(&pool->lock);
>  
> -	if (kref_put(&zhdr->refcount, release_z3fold_page_locked))
> +	if (put_z3fold_locked(zhdr))
>  		return;
>  
>  	if (test_bit(PAGE_STALE, &page->private) ||
> @@ -752,7 +757,7 @@ static void do_compact_page(struct z3fold_header *zhdr, bool locked)
>  
>  	if (!zhdr->foreign_handles && buddy_single(zhdr) &&
>  	    zhdr->mapped_count == 0 && compact_single_buddy(zhdr)) {
> -		if (!kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
> +		if (!put_z3fold_locked(zhdr)) {
>  			clear_bit(PAGE_CLAIMED, &page->private);
>  			z3fold_page_unlock(zhdr);
>  		}
> @@ -878,7 +883,7 @@ static inline struct z3fold_header *__z3fold_alloc(struct z3fold_pool *pool,
>  	return zhdr;
>  
>  out_fail:
> -	if (!kref_put(&zhdr->refcount, release_z3fold_page_locked)) {
> +	if (!put_z3fold_locked(zhdr)) {
>  		add_to_unbuddied(pool, zhdr);
>  		z3fold_page_unlock(zhdr);
>  	}
> @@ -1012,8 +1017,7 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
>  		if (zhdr) {
>  			bud = get_free_buddy(zhdr, chunks);
>  			if (bud == HEADLESS) {
> -				if (!kref_put(&zhdr->refcount,
> -					     release_z3fold_page_locked))
> +				if (!put_z3fold_locked(zhdr))
>  					z3fold_page_unlock(zhdr);
>  				pr_err("No free chunks in unbuddied\n");
>  				WARN_ON(1);
> @@ -1346,7 +1350,7 @@ static void z3fold_page_putback(struct page *page)
>  	if (!list_empty(&zhdr->buddy))
>  		list_del_init(&zhdr->buddy);
>  	INIT_LIST_HEAD(&page->lru);
> -	if (kref_put(&zhdr->refcount, release_z3fold_page_locked))
> +	if (put_z3fold_locked(zhdr))
>  		return;
>  	if (list_empty(&zhdr->buddy))
>  		add_to_unbuddied(pool, zhdr);
>