Re: [PATCH] Documentation/fs: Move swap_[de]activate() to file_operations

[Darrick J. Wong]

On Thu, Nov 14, 2019 at 03:19:43PM -0800, ira.weiny@xxxxxxxxx wrote:
> From: Ira Weiny <ira.weiny@xxxxxxxxx>
> 
> Update the documentation for the move of the swap_* functions out of
> address_space_operations and into file_operations.
> 
> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>

Looks ok,
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>

--D

> ---
> Follow on to the V2 series sent earlier.  If I need to spin a V3 I will squash
> this into patch 2/2 "fs: Move swap_[de]activate to file_operations"
> 
>  Documentation/filesystems/vfs.rst | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst
> index 7d4d09dd5e6d..03a740d7faa4 100644
> --- a/Documentation/filesystems/vfs.rst
> +++ b/Documentation/filesystems/vfs.rst
> @@ -731,8 +731,6 @@ cache in your filesystem.  The following members are defined:
>  					      unsigned long);
>  		void (*is_dirty_writeback) (struct page *, bool *, bool *);
>  		int (*error_remove_page) (struct mapping *mapping, struct page *page);
> -		int (*swap_activate)(struct file *);
> -		int (*swap_deactivate)(struct file *);
>  	};
>  
>  ``writepage``
> @@ -924,16 +922,6 @@ cache in your filesystem.  The following members are defined:
>  	Setting this implies you deal with pages going away under you,
>  	unless you have them locked or reference counts increased.
>  
> -``swap_activate``
> -	Called when swapon is used on a file to allocate space if
> -	necessary and pin the block lookup information in memory.  A
> -	return value of zero indicates success, in which case this file
> -	can be used to back swapspace.
> -
> -``swap_deactivate``
> -	Called during swapoff on files where swap_activate was
> -	successful.
> -
>  
>  The File Object
>  ===============
> @@ -988,6 +976,8 @@ This describes how the VFS can manipulate an open file.  As of kernel
>  					   struct file *file_out, loff_t pos_out,
>  					   loff_t len, unsigned int remap_flags);
>  		int (*fadvise)(struct file *, loff_t, loff_t, int);
> +		int (*swap_activate)(struct file *);
> +		int (*swap_deactivate)(struct file *);
>  	};
>  
>  Again, all methods are called without any locks being held, unless
> @@ -1108,6 +1098,16 @@ otherwise noted.
>  ``fadvise``
>  	possibly called by the fadvise64() system call.
>  
> +``swap_activate``
> +	Called when swapon is used on a file to allocate space if
> +	necessary and pin the block lookup information in memory.  A
> +	return value of zero indicates success, in which case this file
> +	can be used to back swapspace.
> +
> +``swap_deactivate``
> +	Called during swapoff on files where swap_activate was
> +	successful.
> +
>  Note that the file operations are implemented by the specific
>  filesystem in which the inode resides.  When opening a device node
>  (character or block special) most filesystems will call special
> -- 
> 2.21.0
>