[PATCH v4 3/5] block/io: bdrv_common_block_status_above: support bs == base

[Vladimir Sementsov-Ogievskiy]

We are going to reuse bdrv_common_block_status_above in
bdrv_is_allocated_above. bdrv_is_allocated_above may be called with
include_base == false and still bs == base (for ex. from img_rebase()).

So, support this corner case.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/io.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/block/io.c b/block/io.c
index ae1c806720..6f90b322f4 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2458,7 +2458,11 @@ static int coroutine_fn 
bdrv_co_block_status_above(BlockDriverState *bs,
     int ret = 0;
     bool first = true;
 
-    assert(include_base || bs != base);
+    if (!include_base && bs == base) {
+        *pnum = bytes;
+        return 0;
+    }
+
     for (p = bs; include_base || p != base; p = backing_bs(p)) {
         ret = bdrv_co_block_status(p, want_zero, offset, bytes, pnum, map,
                                    file);
-- 
2.18.0