diff --git a/drivers/pcmcia/yenta_socket.c b/drivers/pcmcia/yenta_socket.c
index 84bfc0e85d6b..f15b72c6e57e 100644
--- a/drivers/pcmcia/yenta_socket.c
+++ b/drivers/pcmcia/yenta_socket.c
@@ -636,11 +636,11 @@ static int yenta_search_one_res(struct resource *root, struct resource *res,
 		start = PCIBIOS_MIN_CARDBUS_IO;
 		end = ~0U;
 	} else {
-		unsigned long avail = root->end - root->start;
+		unsigned long avail = resource_size(root);
 		int i;
 		size = BRIDGE_MEM_MAX;
-		if (size > avail/8) {
-			size = (avail+1)/8;
+		if (size > (avail - 1) / 8) {
+			size = avail / 8;
 			/* round size down to next power of 2 */
 			i = 0;
 			while ((size /= 2) != 0)