mm: convert page_get_anon_vma() to folio_get_anon_vma()

With all callers now passing in a folio, rename the function and convert
all callers.  Removes a couple of calls to compound_head() and a reference
to page->mapping.

Link: https://lkml.kernel.org/r/20220902194653.1739778-55-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 22949ff..36ef79b 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2649,7 +2649,7 @@ int split_huge_page_to_list(struct page *page, struct list_head *list)
 		 * is taken to serialise against parallel split or collapse
 		 * operations.
 		 */
-		anon_vma = page_get_anon_vma(&folio->page);
+		anon_vma = folio_get_anon_vma(folio);
 		if (!anon_vma) {
 			ret = -EBUSY;
 			goto out;