| Date | Mon, 10 Jan 2022 20:27:16 -0800 | Subject | Re: [PATCH v2 14/28] mm: Convert page_maybe_dma_pinned() to use a folio | From | John Hubbard <> |
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On 1/9/22 20:23, Matthew Wilcox (Oracle) wrote: > Replace three calls to compound_head() with one. This removes the last > user of compound_pincount(), so remove that helper too. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > --- > include/linux/mm.h | 21 ++++++++------------- > 1 file changed, 8 insertions(+), 13 deletions(-)
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
thanks, -- John Hubbard NVIDIA
> > diff --git a/include/linux/mm.h b/include/linux/mm.h > index bf9624ca61c3..d3769897c8ac 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -934,13 +934,6 @@ static inline int head_compound_pincount(struct page *head) > return atomic_read(compound_pincount_ptr(head)); > } > > -static inline int compound_pincount(struct page *page) > -{ > - VM_BUG_ON_PAGE(!PageCompound(page), page); > - page = compound_head(page); > - return head_compound_pincount(page); > -} > - > static inline void set_compound_order(struct page *page, unsigned int order) > { > page[1].compound_order = order; > @@ -1340,18 +1333,20 @@ void unpin_user_pages(struct page **pages, unsigned long npages); > */ > static inline bool page_maybe_dma_pinned(struct page *page) > { > - if (PageCompound(page)) > - return compound_pincount(page) > 0; > + struct folio *folio = page_folio(page); > + > + if (folio_test_large(folio)) > + return atomic_read(folio_pincount_ptr(folio)) > 0; > > /* > - * page_ref_count() is signed. If that refcount overflows, then > - * page_ref_count() returns a negative value, and callers will avoid > + * folio_ref_count() is signed. If that refcount overflows, then > + * folio_ref_count() returns a negative value, and callers will avoid > * further incrementing the refcount. > * > - * Here, for that overflow case, use the signed bit to count a little > + * Here, for that overflow case, use the sign bit to count a little > * bit higher via unsigned math, and thus still get an accurate result. > */ > - return ((unsigned int)page_ref_count(compound_head(page))) >= > + return ((unsigned int)folio_ref_count(folio)) >= > GUP_PIN_COUNTING_BIAS; > } >
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