mm: migrate_device: use a folio in migrate_device_range()

Save two calls to compound_head() and use folio throughout.

Link: https://lkml.kernel.org/r/20240826065814.1336616-3-wangkefeng.wang@huawei.comSigned-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/migrate_device.c

@@ -898,16 +898,17 @@ int migrate_device_range(unsigned long *src_pfns, unsigned long start,
 	unsigned long i, pfn;
 
 	for (pfn = start, i = 0; i < npages; pfn++, i++) {
-		struct page *page = pfn_to_page(pfn);
+		struct folio *folio;
 
-		if (!get_page_unless_zero(page)) {
+		folio = folio_get_nontail_page(pfn_to_page(pfn));
+		if (!folio) {
 			src_pfns[i] = 0;
 			continue;
 		}
 
-		if (!trylock_page(page)) {
+		if (!folio_trylock(folio)) {
 			src_pfns[i] = 0;
-			put_page(page);
+			folio_put(folio);
 			continue;
 		}