linux-ext4 - Re: [PATCH 02/31] fscrypt: Add some folio helper functions

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Date:   Thu, 26 Jan 2023 19:02:14 -0800
From:   Eric Biggers <ebiggers@...nel.org>
To:     "Matthew Wilcox (Oracle)" <willy@...radead.org>
Cc:     Theodore Tso <tytso@....edu>,
        Andreas Dilger <adilger.kernel@...ger.ca>,
        linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 02/31] fscrypt: Add some folio helper functions

On Thu, Jan 26, 2023 at 08:23:46PM +0000, Matthew Wilcox (Oracle) wrote:
> fscrypt_is_bounce_folio() is the equivalent of fscrypt_is_bounce_page()
> and fscrypt_pagecache_folio() is the equivalent of fscrypt_pagecache_page().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
> ---
>  include/linux/fscrypt.h | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
> index 4f5f8a651213..c2c07d36fb3a 100644
> --- a/include/linux/fscrypt.h
> +++ b/include/linux/fscrypt.h
> @@ -273,6 +273,16 @@ static inline struct page *fscrypt_pagecache_page(struct page *bounce_page)
>  	return (struct page *)page_private(bounce_page);
>  }
>  
> +static inline bool fscrypt_is_bounce_folio(struct folio *folio)
> +{
> +	return folio->mapping == NULL;
> +}
> +
> +static inline struct folio *fscrypt_pagecache_folio(struct folio *bounce_folio)
> +{
> +	return bounce_folio->private;
> +}

ext4_bio_write_folio() is still doing:

	bounce_page = fscrypt_encrypt_pagecache_blocks(&folio->page, ...);

Should it be creating a "bounce folio" instead, or is that not in the scope of
this patchset?

- Eric