migrate: expand the use of folio in __migrate_device_pages()

Removes a few calls to compound_head() and a call to page_mapping().

Link: https://lkml.kernel.org/r/20240423225552.4113447-5-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Eric Biggers <ebiggers@google.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index b929b450b77c3dac2266e2da5969f02c0de211ba..7e0712493d1f48e5429c8d2ef5f7ebc18f5f14f4 100644 (file)
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -696,6 +696,7 @@ static void __migrate_device_pages(unsigned long *src_pfns,
                struct page *newpage = migrate_pfn_to_page(dst_pfns[i]);
                struct page *page = migrate_pfn_to_page(src_pfns[i]);
                struct address_space *mapping;
+               struct folio *folio;
                int r;
 
                if (!newpage) {
@@ -730,15 +731,12 @@ static void __migrate_device_pages(unsigned long *src_pfns,
                        continue;
                }
 
-               mapping = page_mapping(page);
+               folio = page_folio(page);
+               mapping = folio_mapping(folio);
 
                if (is_device_private_page(newpage) ||
                    is_device_coherent_page(newpage)) {
                        if (mapping) {
-                               struct folio *folio;
-
-                               folio = page_folio(page);
-
                                /*
                                 * For now only support anonymous memory migrating to
                                 * device private or coherent memory.
@@ -761,11 +759,10 @@ static void __migrate_device_pages(unsigned long *src_pfns,
 
                if (migrate && migrate->fault_page == page)
                        r = migrate_folio_extra(mapping, page_folio(newpage),
-                                               page_folio(page),
-                                               MIGRATE_SYNC_NO_COPY, 1);
+                                               folio, MIGRATE_SYNC_NO_COPY, 1);
                else
                        r = migrate_folio(mapping, page_folio(newpage),
-                                       page_folio(page), MIGRATE_SYNC_NO_COPY);
+                                       folio, MIGRATE_SYNC_NO_COPY);
                if (r != MIGRATEPAGE_SUCCESS)
                        src_pfns[i] &= ~MIGRATE_PFN_MIGRATE;
        }