aio: Convert to migrate_folio

Use a folio throughout this function.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/aio.c

@@ -400,8 +400,8 @@ static const struct file_operations aio_ring_fops = {
 };
 
 #if IS_ENABLED(CONFIG_MIGRATION)
-static int aio_migratepage(struct address_space *mapping, struct page *new,
-			struct page *old, enum migrate_mode mode)
+static int aio_migrate_folio(struct address_space *mapping, struct folio *dst,
+			struct folio *src, enum migrate_mode mode)
 {
 	struct kioctx *ctx;
 	unsigned long flags;
@@ -435,10 +435,10 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
 		goto out;
 	}
 
-	idx = old->index;
+	idx = src->index;
 	if (idx < (pgoff_t)ctx->nr_pages) {
-		/* Make sure the old page hasn't already been changed */
-		if (ctx->ring_pages[idx] != old)
+		/* Make sure the old folio hasn't already been changed */
+		if (ctx->ring_pages[idx] != &src->page)
 			rc = -EAGAIN;
 	} else
 		rc = -EINVAL;
@@ -447,27 +447,27 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
 		goto out_unlock;
 
 	/* Writeback must be complete */
-	BUG_ON(PageWriteback(old));
-	get_page(new);
+	BUG_ON(folio_test_writeback(src));
+	folio_get(dst);
 
-	rc = migrate_page_move_mapping(mapping, new, old, 1);
+	rc = folio_migrate_mapping(mapping, dst, src, 1);
 	if (rc != MIGRATEPAGE_SUCCESS) {
-		put_page(new);
+		folio_put(dst);
 		goto out_unlock;
 	}
 
 	/* Take completion_lock to prevent other writes to the ring buffer
-	 * while the old page is copied to the new.  This prevents new
+	 * while the old folio is copied to the new.  This prevents new
 	 * events from being lost.
 	 */
 	spin_lock_irqsave(&ctx->completion_lock, flags);
-	migrate_page_copy(new, old);
-	BUG_ON(ctx->ring_pages[idx] != old);
-	ctx->ring_pages[idx] = new;
+	folio_migrate_copy(dst, src);
+	BUG_ON(ctx->ring_pages[idx] != &src->page);
+	ctx->ring_pages[idx] = &dst->page;
 	spin_unlock_irqrestore(&ctx->completion_lock, flags);
 
-	/* The old page is no longer accessible. */
-	put_page(old);
+	/* The old folio is no longer accessible. */
+	folio_put(src);
 
 out_unlock:
 	mutex_unlock(&ctx->ring_lock);
@@ -475,13 +475,13 @@ static int aio_migratepage(struct address_space *mapping, struct page *new,
 	spin_unlock(&mapping->private_lock);
 	return rc;
 }
+#else
+#define aio_migrate_folio NULL
 #endif
 
 static const struct address_space_operations aio_ctx_aops = {
 	.dirty_folio	= noop_dirty_folio,
-#if IS_ENABLED(CONFIG_MIGRATION)
-	.migratepage	= aio_migratepage,
-#endif
+	.migrate_folio	= aio_migrate_folio,
 };
 
 static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)