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Message-ID: <1e862dbf-1618-c546-f0d9-ca54f129285c@suse.cz>
Date:   Tue, 10 Jan 2023 15:28:12 +0100
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Subject: Re: [PATCH] mm/sl{a,u}b: fix wrong usages of folio_page() for getting
 head pages
Content-Language: en-US
To:     SeongJae Park <sj@kernel.org>, akpm@linux-foundation.org
Cc:     willy@infradead.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Hyeonggon Yoo <42.hyeyoo@gmail.com>
References: <20230110005124.1609-1-sj@kernel.org>
From:   Vlastimil Babka <vbabka@suse.cz>
In-Reply-To: <20230110005124.1609-1-sj@kernel.org>
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On 1/10/23 01:51, SeongJae Park wrote:
> The standard idiom for getting head page of a given folio is
> '&folio->page', but some are wrongly using 'folio_page(folio, 0)' for
> the purpose.  Fix those to use the idiom.
> 
> Suggested-by: Matthew Wilcox <willy@infradead.org>
> Signed-off-by: SeongJae Park <sj@kernel.org>

Thanks, pushed to slab/for-6.3/cleanups

> ---
>  mm/slab.c | 4 ++--
>  mm/slub.c | 2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/slab.c b/mm/slab.c
> index b77be9c6d6b1..a5398676dc60 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -1389,7 +1389,7 @@ static void kmem_freepages(struct kmem_cache *cachep, struct slab *slab)
>  
>  	BUG_ON(!folio_test_slab(folio));
>  	__slab_clear_pfmemalloc(slab);
> -	page_mapcount_reset(folio_page(folio, 0));
> +	page_mapcount_reset(&folio->page);
>  	folio->mapping = NULL;
>  	/* Make the mapping reset visible before clearing the flag */
>  	smp_wmb();
> @@ -1398,7 +1398,7 @@ static void kmem_freepages(struct kmem_cache *cachep, struct slab *slab)
>  	if (current->reclaim_state)
>  		current->reclaim_state->reclaimed_slab += 1 << order;
>  	unaccount_slab(slab, order, cachep);
> -	__free_pages(folio_page(folio, 0), order);
> +	__free_pages(&folio->page, order);
>  }
>  
>  static void kmem_rcu_free(struct rcu_head *head)
> diff --git a/mm/slub.c b/mm/slub.c
> index 67020074ecb4..d5f20c062004 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2066,7 +2066,7 @@ static void __free_slab(struct kmem_cache *s, struct slab *slab)
>  	if (current->reclaim_state)
>  		current->reclaim_state->reclaimed_slab += pages;
>  	unaccount_slab(slab, order, s);
> -	__free_pages(folio_page(folio, 0), order);
> +	__free_pages(&folio->page, order);
>  }
>  
>  static void rcu_free_slab(struct rcu_head *h)