md: move two macros into md.h

Both raid1 and raid10 share common resync
block size and page count, so move them into md.h.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Shaohua Li <shli@fb.com>
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 7a7847d..31d2d70 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -718,4 +718,9 @@
 	    !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors)
 		mddev->queue->limits.max_write_same_sectors = 0;
 }
+
+/* Maximum size of each resync request */
+#define RESYNC_BLOCK_SIZE (64*1024)
+#define RESYNC_PAGES ((RESYNC_BLOCK_SIZE + PAGE_SIZE-1) / PAGE_SIZE)
+
 #endif /* _MD_MD_H */