Re: [GIT PULL] Staging/IIO driver patches for 5.4-rc1

[Gao Xiang]

Hi Christoph,

On Wed, Sep 18, 2019 at 11:24:12AM -0700, Christoph Hellwig wrote:
> Just as a note of record:  I don't think either file system move
> is a good idea.  erofs still needs a lot of work, especially in
> interacting with the mm code like abusing page->mapping.

I know what you mean, that is a known stuff in the TODO list,
Z_EROFS_MAPPING_STAGING page->mapping just be used as a temporary
page mark since page->private is already pointed to another
structure, It's now be marked as an non-movable and anon pseudo
mapping and most mm code just skip this case.

I think a better way is to use a real address_space structure for
page->mapping to point. It's easy to update but I need some time
to verify. If I am wrong, please point it out...

Thanks,
Gao Xiang