[PATCH] virtio-vdpa: Fix unchecked call to NULL set_vq_affinity

[Dragos Tatulea]

The referenced patch calls set_vq_affinity without checking if the op is
valid. This patch adds the check.

Fixes: 3dad56823b53 ("virtio-vdpa: Support interrupt affinity spreading mechanism")
Reviewed-by: Gal Pressman <gal@xxxxxxxxxx>
Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
---
 drivers/virtio/virtio_vdpa.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_vdpa.c b/drivers/virtio/virtio_vdpa.c
index eb6aee8c06b2..989e2d7184ce 100644
--- a/drivers/virtio/virtio_vdpa.c
+++ b/drivers/virtio/virtio_vdpa.c
@@ -385,7 +385,9 @@ static int virtio_vdpa_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
 			err = PTR_ERR(vqs[i]);
 			goto err_setup_vq;
 		}
-		ops->set_vq_affinity(vdpa, i, &masks[i]);
+
+		if (ops->set_vq_affinity)
+			ops->set_vq_affinity(vdpa, i, &masks[i]);
 	}
 
 	cb.callback = virtio_vdpa_config_cb;
-- 
2.40.1