| Subject | Re: [PATCH 04/22] mm: don't clear ->mapping in hmm_devmem_free | From | John Hubbard <> | Date | Thu, 13 Jun 2019 18:46:29 -0700 |
| |
On 6/13/19 2:43 AM, Christoph Hellwig wrote: > ->mapping isn't even used by HMM users, and the field at the same offset > in the zone_device part of the union is declared as pad. (Which btw is > rather confusing, as DAX uses ->pgmap and ->mapping from two different > sides of the union, but DAX doesn't use hmm_devmem_free). > > Signed-off-by: Christoph Hellwig <hch@lst.de> > --- > mm/hmm.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/mm/hmm.c b/mm/hmm.c > index 0c62426d1257..e1dc98407e7b 100644 > --- a/mm/hmm.c > +++ b/mm/hmm.c > @@ -1347,8 +1347,6 @@ static void hmm_devmem_free(struct page *page, void *data) > { > struct hmm_devmem *devmem = data; > > - page->mapping = NULL; > - > devmem->ops->free(devmem, page); > } > >
Yes, I think that line was unnecessary. I see from git history that it was originally being set to NULL from within __put_devmap_managed_page(), and then in commit 2fa147bdbf672c53386a8f5f2c7fe358004c3ef8, Dan moved it out of there, and stashed in specifically here. But it appears to have been unnecessary from the beginning.
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
thanks, -- John Hubbard NVIDIA
|