linux-ext4 - Re: [PATCH 01/10] highmem: Add folio_release

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Date:   Tue, 3 Oct 2023 12:41:28 +0200
From:   Jan Kara <jack@...e.cz>
To:     "Matthew Wilcox (Oracle)" <willy@...radead.org>
Cc:     Jan Kara <jack@...e.com>, linux-ext4@...r.kernel.org,
        linux-fsdevel@...r.kernel.org,
        "Fabio M . De Francesco" <fmdefrancesco@...il.com>
Subject: Re: [PATCH 01/10] highmem: Add folio_release_kmap()

On Thu 21-09-23 21:07:38, Matthew Wilcox (Oracle) wrote:
> This is the folio equivalent of unmap_and_put_page(), which remains as
> a wrapper for it.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>

I'm missing a patch 10/10 in this series (and a coverletter would be nice
as well)... What's there ;)?

								Honza

> ---
>  include/linux/highmem.h | 18 ++++++++++++++++--
>  1 file changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/highmem.h b/include/linux/highmem.h
> index 99c474de800d..4cacc0e43b51 100644
> --- a/include/linux/highmem.h
> +++ b/include/linux/highmem.h
> @@ -551,10 +551,24 @@ static inline void folio_zero_range(struct folio *folio,
>  	zero_user_segments(&folio->page, start, start + length, 0, 0);
>  }
>  
> -static inline void unmap_and_put_page(struct page *page, void *addr)
> +/**
> + * folio_release_kmap - Unmap a folio and drop a refcount.
> + * @folio: The folio to release.
> + * @addr: The address previously returned by a call to kmap_local_folio().
> + *
> + * It is common, eg in directory handling to kmap a folio.  This function
> + * unmaps the folio and drops the refcount that was being held to keep the
> + * folio alive while we accessed it.
> + */
> +static inline void folio_release_kmap(struct folio *folio, void *addr)
>  {
>  	kunmap_local(addr);
> -	put_page(page);
> +	folio_put(folio);
> +}
> +
> +static inline void unmap_and_put_page(struct page *page, void *addr)
> +{
> +	folio_release_kmap(page_folio(page), addr);
>  }
>  
>  #endif /* _LINUX_HIGHMEM_H */
> -- 
> 2.40.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR