On Wed, Mar 10, 2021 at 04:29:51PM +0000, Al Viro wrote:

On Tue, Mar 09, 2021 at 04:53:42PM +0100, Christoph Hellwig wrote:

quoted

Just use the generic anon_inode file system.

Umm...  The only problem I see here is the lifetime rules for
that module, and that's not something introduced in this patchset.
Said that, looks like the logics around that place is duplicated in
cmm.c, vmw_balloon.c and virtion_balloon.c and I wonder if it would
be better off with a helper in mm/balloon.c to be used for that setup...

Independ of all other discussions untangling that mess does seem
very useful.