[PATCH v2 4/4] block/blkio: use blkio_set_int("fd") to check fd support

[Stefano Garzarella]

Setting the `fd` property fails with virtio-blk-* libblkio drivers
that do not support fd passing since
https://gitlab.com/libblkio/libblkio/-/merge_requests/208.

Getting the `fd` property, on the other hand, always succeeds for
virtio-blk-* libblkio drivers even when they don't support fd passing.

This patch switches to setting the `fd` property because it is a
better mechanism for probing fd passing support than getting the `fd`
property.

Signed-off-by: Stefano Garzarella <sgarz...@redhat.com>
---

Notes:
    v2:
    - changed commit description [Stefan]

 block/blkio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/blkio.c b/block/blkio.c
index 72b46d61fd..8e7ce42c79 100644
--- a/block/blkio.c
+++ b/block/blkio.c
@@ -690,7 +690,7 @@ static int blkio_virtio_blk_connect(BlockDriverState *bs, 
QDict *options,
         return -EINVAL;
     }
 
-    if (blkio_get_int(s->blkio, "fd", &fd) == 0) {
+    if (blkio_set_int(s->blkio, "fd", -1) == 0) {
         fd_supported = true;
     }
 
-- 
2.41.0