linux-kernel - Re: [PATCH 02/10] mm/nommu: use file_has_valid_mmap

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Message-ID: <gtjkxyljepqjjahbxic5xulqdxqresuuyfdr2i2vcc4tewy5yp@ziyb3wcdlvyw>
Date: Tue, 17 Jun 2025 12:05:39 +0200
From: Jan Kara <jack@...e.cz>
To: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
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Subject: Re: [PATCH 02/10] mm/nommu: use file_has_valid_mmap_hooks() helper

On Mon 16-06-25 20:33:21, Lorenzo Stoakes wrote:
> Since commit c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file
> callback"), the f_op->mmap() hook has been deprecated in favour of
> f_op->mmap_prepare().
> 
> Therefore, update the check for file operations supporting mmap() by using
> the file_has_valid_mmap_hooks() helper function, which checks for either
> f_op->mmap or f_op->mmap_prepare rather than checking only for f_op->mmap
> directly.
> 
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

Maybe Fixes tag would be appropriate here?

								Honza

> ---
>  mm/nommu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/nommu.c b/mm/nommu.c
> index b624acec6d2e..38c22ea0a95c 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -719,7 +719,7 @@ static int validate_mmap_request(struct file *file,
>  
>  	if (file) {
>  		/* files must support mmap */
> -		if (!file->f_op->mmap)
> +		if (!file_has_valid_mmap_hooks(file))
>  			return -ENODEV;
>  
>  		/* work out if what we've got could possibly be shared
> -- 
> 2.49.0
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR