[PATCH net-next 2/3] virtio_net: Hold RTNL for NAPI to queue mapping

[Joe Damato <jdamato@fastly.com>]

Prepare for NAPI to queue mapping by holding RTNL in code paths where
NAPIs will be mapped to queue IDs and RTNL is not currently held.

Signed-off-by: Joe Damato <jdamato@fastly.com>
---
 drivers/net/virtio_net.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index cff18c66b54a..4e88d352d3eb 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -2803,11 +2803,17 @@ static void virtnet_napi_do_enable(struct virtqueue *vq,
 	local_bh_enable();
 }
 
-static void virtnet_napi_enable(struct virtqueue *vq, struct napi_struct *napi)
+static void virtnet_napi_enable_lock(struct virtqueue *vq,
+				     struct napi_struct *napi)
 {
 	virtnet_napi_do_enable(vq, napi);
 }
 
+static void virtnet_napi_enable(struct virtqueue *vq, struct napi_struct *napi)
+{
+	virtnet_napi_enable_lock(vq, napi);
+}
+
 static void virtnet_napi_tx_enable(struct virtnet_info *vi,
 				   struct virtqueue *vq,
 				   struct napi_struct *napi)
@@ -2844,7 +2850,7 @@ static void refill_work(struct work_struct *work)
 
 		napi_disable(&rq->napi);
 		still_empty = !try_fill_recv(vi, rq, GFP_KERNEL);
-		virtnet_napi_enable(rq->vq, &rq->napi);
+		virtnet_napi_enable_lock(rq->vq, &rq->napi);
 
 		/* In theory, this can happen: if we don't get any buffers in
 		 * we will *never* try to fill again.
@@ -5621,8 +5627,11 @@ static void virtnet_freeze_down(struct virtio_device *vdev)
 	netif_tx_lock_bh(vi->dev);
 	netif_device_detach(vi->dev);
 	netif_tx_unlock_bh(vi->dev);
-	if (netif_running(vi->dev))
+	if (netif_running(vi->dev)) {
+		rtnl_lock();
 		virtnet_close(vi->dev);
+		rtnl_unlock();
+	}
 }
 
 static int init_vqs(struct virtnet_info *vi);
@@ -5642,7 +5651,9 @@ static int virtnet_restore_up(struct virtio_device *vdev)
 	enable_rx_mode_work(vi);
 
 	if (netif_running(vi->dev)) {
+		rtnl_lock();
 		err = virtnet_open(vi->dev);
+		rtnl_unlock();
 		if (err)
 			return err;
 	}
-- 
2.25.1