[PATCH net v2] virtio_net: Fix error unwinding of XDP initialization

[Feng Liu <feliu@xxxxxxxxxx>]

When initializing XDP in virtnet_open(), some rq xdp initialization
may hit an error causing net device open failed. However, previous
rqs have already initialized XDP and enabled NAPI, which is not the
expected behavior. Need to roll back the previous rq initialization
to avoid leaks in error unwinding of init code.

Also extract a helper function of disable queue pairs, and use newly
introduced helper function in error unwinding and virtnet_close;

Fixes: 754b8a21a96d ("virtio_net: setup xdp_rxq_info")
Signed-off-by: Feng Liu <feliu@xxxxxxxxxx>
Reviewed-by: William Tu <witu@xxxxxxxxxx>
Reviewed-by: Parav Pandit <parav@xxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
 drivers/net/virtio_net.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 8d8038538fc4..5cd78e154d14 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1868,6 +1868,13 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
 	return received;
 }
 
+static void virtnet_disable_qp(struct virtnet_info *vi, int qp_index)
+{
+	virtnet_napi_tx_disable(&vi->sq[qp_index].napi);
+	napi_disable(&vi->rq[qp_index].napi);
+	xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq);
+}
+
 static int virtnet_open(struct net_device *dev)
 {
 	struct virtnet_info *vi = netdev_priv(dev);
@@ -1883,20 +1890,27 @@ static int virtnet_open(struct net_device *dev)
 
 		err = xdp_rxq_info_reg(&vi->rq[i].xdp_rxq, dev, i, vi->rq[i].napi.napi_id);
 		if (err < 0)
-			return err;
+			goto err_xdp_info_reg;
 
 		err = xdp_rxq_info_reg_mem_model(&vi->rq[i].xdp_rxq,
 						 MEM_TYPE_PAGE_SHARED, NULL);
-		if (err < 0) {
-			xdp_rxq_info_unreg(&vi->rq[i].xdp_rxq);
-			return err;
-		}
+		if (err < 0)
+			goto err_xdp_reg_mem_model;
 
 		virtnet_napi_enable(vi->rq[i].vq, &vi->rq[i].napi);
 		virtnet_napi_tx_enable(vi, vi->sq[i].vq, &vi->sq[i].napi);
 	}
 
 	return 0;
+
+	/* error unwinding of xdp init */
+err_xdp_reg_mem_model:
+	xdp_rxq_info_unreg(&vi->rq[i].xdp_rxq);
+err_xdp_info_reg:
+	for (i = i - 1; i >= 0; i--)
+		virtnet_disable_qp(vi, i);
+
+	return err;
 }
 
 static int virtnet_poll_tx(struct napi_struct *napi, int budget)
@@ -2305,11 +2319,8 @@ static int virtnet_close(struct net_device *dev)
 	/* Make sure refill_work doesn't re-enable napi! */
 	cancel_delayed_work_sync(&vi->refill);
 
-	for (i = 0; i < vi->max_queue_pairs; i++) {
-		virtnet_napi_tx_disable(&vi->sq[i].napi);
-		napi_disable(&vi->rq[i].napi);
-		xdp_rxq_info_unreg(&vi->rq[i].xdp_rxq);
-	}
+	for (i = 0; i < vi->max_queue_pairs; i++)
+		virtnet_disable_qp(vi, i);
 
 	return 0;
 }
-- 
2.37.1 (Apple Git-137.1)