mm/gup: Convert gup_huge_pgd() to use a folio

Use the new folio-based APIs.  This was the last user of
try_grab_compound_head(), so remove it.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>

mm/gup.c

@@ -133,12 +133,6 @@ struct folio *try_grab_folio(struct page *page, int refs, unsigned int flags)
 	return NULL;
 }
 
-static inline struct page *try_grab_compound_head(struct page *page,
-		int refs, unsigned int flags)
-{
-	return &try_grab_folio(page, refs, flags)->page;
-}
-
 static void gup_put_folio(struct folio *folio, int refs, unsigned int flags)
 {
 	if (flags & FOLL_PIN) {
@@ -2560,7 +2554,8 @@ static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr,
 			struct page **pages, int *nr)
 {
 	int refs;
-	struct page *head, *page;
+	struct page *page;
+	struct folio *folio;
 
 	if (!pgd_access_permitted(orig, flags & FOLL_WRITE))
 		return 0;
@@ -2570,17 +2565,17 @@ static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr,
 	page = nth_page(pgd_page(orig), (addr & ~PGDIR_MASK) >> PAGE_SHIFT);
 	refs = record_subpages(page, addr, end, pages + *nr);
 
-	head = try_grab_compound_head(pgd_page(orig), refs, flags);
-	if (!head)
+	folio = try_grab_folio(page, refs, flags);
+	if (!folio)
 		return 0;
 
 	if (unlikely(pgd_val(orig) != pgd_val(*pgdp))) {
-		put_compound_head(head, refs, flags);
+		gup_put_folio(folio, refs, flags);
 		return 0;
 	}
 
 	*nr += refs;
-	SetPageReferenced(head);
+	folio_set_referenced(folio);
 	return 1;
 }