virtio-mem: generalize virtio_mem_owned_mb()

Avoid using memory block ids. Rename it to virtio_mem_contains_range().

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/20201112133815.13332-13-david@redhat.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/virtio/virtio_mem.c

@@ -512,12 +512,13 @@ static bool virtio_mem_overlaps_range(struct virtio_mem *vm,
 }
 
 /*
- * Test if a virtio-mem device owns a memory block. Can be called from
+ * Test if a virtio-mem device contains a given range. Can be called from
  * (notifier) callbacks lockless.
  */
-static bool virtio_mem_owned_mb(struct virtio_mem *vm, unsigned long mb_id)
+static bool virtio_mem_contains_range(struct virtio_mem *vm, uint64_t start,
+				      uint64_t size)
 {
-	return mb_id >= vm->first_mb_id && mb_id <= vm->last_mb_id;
+	return start >= vm->addr && start + size <= vm->addr + vm->region_size;
 }
 
 static int virtio_mem_notify_going_online(struct virtio_mem *vm,
@@ -871,7 +872,7 @@ static void virtio_mem_online_page_cb(struct page *page, unsigned int order)
 	 */
 	rcu_read_lock();
 	list_for_each_entry_rcu(vm, &virtio_mem_devices, next) {
-		if (!virtio_mem_owned_mb(vm, mb_id))
+		if (!virtio_mem_contains_range(vm, addr, PFN_PHYS(1 << order)))
 			continue;
 
 		sb_id = virtio_mem_phys_to_sb_id(vm, addr);