vhost: fix error handling in RESET_OWNER ioctl

RESET_OWNER ioctl would leave the fd in a bad state if
memory allocation failed: device is stopped
but owner is not reset. Make state changes
after allocating memory, such that a failed
ioctl has no effect.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
index 91d6f060aade..be65414d5bb1 100644
--- a/drivers/vhost/test.c
+++ b/drivers/vhost/test.c
@@ -219,13 +219,20 @@ static long vhost_test_reset_owner(struct vhost_test *n)
 {
         void *priv = NULL;
         long err;
+        struct vhost_memory *memory;
+
         mutex_lock(&n->dev.mutex);
         err = vhost_dev_check_owner(&n->dev);
         if (err)
                 goto done;
+        memory = vhost_dev_reset_owner_prepare();
+        if (!memory) {
+                err = -ENOMEM;
+                goto done;
+        }
         vhost_test_stop(n, &priv);
         vhost_test_flush(n);
-        err = vhost_dev_reset_owner(&n->dev);
+        vhost_dev_reset_owner(&n->dev, memory);
 done:
         mutex_unlock(&n->dev.mutex);
         return err;