[PATCH v3 3/9] virtio-ccw: Fix rc check in read configuration path

[Eric Farman <farman@linux.ibm.com>]

Both the read and write config paths use wrappers around cds->op_handler,
depending on the direction the I/O is flowing. But they expect opposite
values in the returned variable to indicate success.

Fix this by unifying those checks, where CCW_CMD_READ_CONF needs to
see !ret as success. The end result is some erroneous data in the
SCSW response data, but the overall success/failure is correct.

Cc: qemu-stable@nongnu.org
Fixes: d895d25ae2 ("s390x: css: report errors from ccw_dstream_read/write")
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
 hw/s390x/virtio-ccw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index f46f936150..11441e56c1 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -475,7 +475,7 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw)
         } else {
             virtio_bus_get_vdev_config(&dev->bus, vdev->config);
             ret = ccw_dstream_write_buf(&sch->cds, vdev->config, len);
-            if (ret) {
+            if (!ret) {
                 sch->curr_status.scsw.count = ccw.count - len;
             }
         }
-- 
2.53.0