mm: remove is_longterm_pinnable_page() and reimplement folio_is_longterm_pinnable()

folio_is_longterm_pinnable() already exists as a wrapper function.  Now
that the whole implementation of is_longterm_pinnable_page() can be
implemented using folios, folio_is_longterm_pinnable() can be made its own
standalone function - and we can remove is_longterm_pinnable_page().

Link: https://lkml.kernel.org/r/20230614021312.34085-6-vishal.moola@gmail.comSigned-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/mm.h

@@ -1902,39 +1902,35 @@ static inline bool page_needs_cow_for_dma(struct vm_area_struct *vma,
 	return page_maybe_dma_pinned(page);
 }
 
-/* MIGRATE_CMA and ZONE_MOVABLE do not allow pin pages */
+/* MIGRATE_CMA and ZONE_MOVABLE do not allow pin folios */
 #ifdef CONFIG_MIGRATION
-static inline bool is_longterm_pinnable_page(struct page *page)
+static inline bool folio_is_longterm_pinnable(struct folio *folio)
 {
 #ifdef CONFIG_CMA
-	int mt = get_pageblock_migratetype(page);
+	int mt = folio_migratetype(folio);
 
 	if (mt == MIGRATE_CMA || mt == MIGRATE_ISOLATE)
 		return false;
 #endif
 	/* The zero page may always be pinned */
-	if (is_zero_pfn(page_to_pfn(page)))
+	if (is_zero_pfn(folio_pfn(folio)))
 		return true;
 
 	/* Coherent device memory must always allow eviction. */
-	if (is_device_coherent_page(page))
+	if (folio_is_device_coherent(folio))
 		return false;
 
-	/* Otherwise, non-movable zone pages can be pinned. */
-	return !is_zone_movable_page(page);
+	/* Otherwise, non-movable zone folios can be pinned. */
+	return !folio_is_zone_movable(folio);
+
 }
 #else
-static inline bool is_longterm_pinnable_page(struct page *page)
+static inline bool folio_is_longterm_pinnable(struct folio *folio)
 {
 	return true;
 }
 #endif
 
-static inline bool folio_is_longterm_pinnable(struct folio *folio)
-{
-	return is_longterm_pinnable_page(&folio->page);
-}
-
 static inline void set_page_zone(struct page *page, enum zone_type zone)
 {
 	page->flags &= ~(ZONES_MASK << ZONES_PGSHIFT);