[PATCH] block/blkio: do not use open flags in qemu_open()

[Stefano Garzarella]

qemu_open() in blkio_virtio_blk_common_open() is used to open the
character device (e.g. /dev/vhost-vdpa-0 or /dev/vfio/vfio) or in
the future eventually the unix socket.

In all these cases we cannot open the path in read-only mode,
when the `read-only` option of blockdev is on, because the exchange
of IOCTL commands for example will fail.

In order to open the device read-only, we have to use the `read-only`
property of the libblkio driver as we already do in blkio_file_open().

Fixes: cad2ccc395 ("block/blkio: use qemu_open() to support fd passing for 
virtio-blk")
Reported-by: Qing Wang <qinwang@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 block/blkio.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/block/blkio.c b/block/blkio.c
index 1798648134..fe9bf8ea5f 100644
--- a/block/blkio.c
+++ b/block/blkio.c
@@ -686,15 +686,7 @@ static int blkio_virtio_blk_common_open(BlockDriverState 
*bs,
      * layer through the "/dev/fdset/N" special path.
      */
     if (fd_supported) {
-        int open_flags;
-
-        if (flags & BDRV_O_RDWR) {
-            open_flags = O_RDWR;
-        } else {
-            open_flags = O_RDONLY;
-        }
-
-        fd = qemu_open(path, open_flags, errp);
+        fd = qemu_open(path, O_RDWR, errp);
         if (fd < 0) {
             return -EINVAL;
         }
-- 
2.41.0