virtio-mem: generalize virtio_mem_overlaps_range()

Avoid using memory block ids. While at it, use uint64_t for
address/size.

This is a preparation for Big Block Mode (BBM).
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Link: https://lore.kernel.org/r/20201112133815.13332-14-david@redhat.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/virtio/virtio_mem.c

@@ -501,14 +501,10 @@ static int virtio_mem_translate_node_id(struct virtio_mem *vm, uint16_t node_id)
  * Test if a virtio-mem device overlaps with the given range. Can be called
  * from (notifier) callbacks lockless.
  */
-static bool virtio_mem_overlaps_range(struct virtio_mem *vm,
-				      unsigned long start, unsigned long size)
+static bool virtio_mem_overlaps_range(struct virtio_mem *vm, uint64_t start,
+				      uint64_t size)
 {
-	unsigned long dev_start = virtio_mem_mb_id_to_phys(vm->first_mb_id);
-	unsigned long dev_end = virtio_mem_mb_id_to_phys(vm->last_mb_id) +
-				memory_block_size_bytes();
-
-	return start < dev_end && dev_start < start + size;
+	return start < vm->addr + vm->region_size && vm->addr < start + size;
 }
 
 /*