On Wed 10-09-25 21:22:04, Lorenzo Stoakes wrote:
> Now we have introduced the ability to specify that actions should be taken
> after a VMA is established via the vm_area_desc->action field as specified
> in mmap_prepare, update both the VFS documentation and the porting guide to
> describe this.
>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoa...@oracle.com>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <j...@suse.cz>
Honza
> ---
> Documentation/filesystems/porting.rst | 5 +++++
> Documentation/filesystems/vfs.rst | 4 ++++
> 2 files changed, 9 insertions(+)
>
> diff --git a/Documentation/filesystems/porting.rst
> b/Documentation/filesystems/porting.rst
> index 85f590254f07..6743ed0b9112 100644
> --- a/Documentation/filesystems/porting.rst
> +++ b/Documentation/filesystems/porting.rst
> @@ -1285,3 +1285,8 @@ rather than a VMA, as the VMA at this stage is not yet
> valid.
> The vm_area_desc provides the minimum required information for a filesystem
> to initialise state upon memory mapping of a file-backed region, and output
> parameters for the file system to set this state.
> +
> +In nearly all cases, this is all that is required for a filesystem. However,
> if
> +a filesystem needs to perform an operation such a pre-population of page
> tables,
> +then that action can be specified in the vm_area_desc->action field, which
> can
> +be configured using the mmap_action_*() helpers.
> diff --git a/Documentation/filesystems/vfs.rst
> b/Documentation/filesystems/vfs.rst
> index 486a91633474..9e96c46ee10e 100644
> --- a/Documentation/filesystems/vfs.rst
> +++ b/Documentation/filesystems/vfs.rst
> @@ -1236,6 +1236,10 @@ otherwise noted.
> file-backed memory mapping, most notably establishing relevant
> private state and VMA callbacks.
>
> + If further action such as pre-population of page tables is required,
> + this can be specified by the vm_area_desc->action field and related
> + parameters.
> +
> 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
> --
> 2.51.0
>
--
Jan Kara <j...@suse.com>
SUSE Labs, CR
