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.stoakes@xxxxxxxxxx> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@xxxxxxx> 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 <jack@xxxxxxxx> SUSE Labs, CR
