gve: guard XSK operations on the existence of queues

This patch predicates the enabling and disabling of XSK pools on the
existence of queues. As it stands, if the interface is down, disabling
or enabling XSK pools would result in a crash, as the RX queue pointer
would be NULL. XSK pool registration will occur as part of the next
interface up.

Similarly, xsk_wakeup needs be guarded against queues disappearing
while the function is executing, so a check against the
GVE_PRIV_FLAGS_NAPI_ENABLED flag is added to synchronize with the
disabling of the bit and the synchronize_net() in gve_turndown.

Fixes: fd8e403 ("gve: Add AF_XDP zero-copy support for GQI-QPL format")
Cc: [email protected]
Signed-off-by: Joshua Washington <[email protected]>
Signed-off-by: Praveen Kaligineedi <[email protected]>
Reviewed-by: Praveen Kaligineedi <[email protected]>
Reviewed-by: Shailend Chand <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Reviewed-by: Larysa Zaremba <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: josh8551021

drivers/net/ethernet/google/gve/gve_main.c

@@ -1623,8 +1623,8 @@ static int gve_xsk_pool_enable(struct net_device *dev,
 	if (err)
 		return err;
 
-	/* If XDP prog is not installed, return */
-	if (!priv->xdp_prog)
+	/* If XDP prog is not installed or interface is down, return. */
+	if (!priv->xdp_prog || !netif_running(dev))
 		return 0;
 
 	rx = &priv->rx[qid];
@@ -1669,21 +1669,16 @@ static int gve_xsk_pool_disable(struct net_device *dev,
 	if (qid >= priv->rx_cfg.num_queues)
 		return -EINVAL;
 
-	/* If XDP prog is not installed, unmap DMA and return */
-	if (!priv->xdp_prog)
+	/* If XDP prog is not installed or interface is down, unmap DMA and
+	 * return.
+	 */
+	if (!priv->xdp_prog || !netif_running(dev))
 		goto done;
 
-	tx_qid = gve_xdp_tx_queue_id(priv, qid);
-	if (!netif_running(dev)) {
-		priv->rx[qid].xsk_pool = NULL;
-		xdp_rxq_info_unreg(&priv->rx[qid].xsk_rxq);
-		priv->tx[tx_qid].xsk_pool = NULL;
-		goto done;
-	}
-
 	napi_rx = &priv->ntfy_blocks[priv->rx[qid].ntfy_id].napi;
 	napi_disable(napi_rx); /* make sure current rx poll is done */
 
+	tx_qid = gve_xdp_tx_queue_id(priv, qid);
 	napi_tx = &priv->ntfy_blocks[priv->tx[tx_qid].ntfy_id].napi;
 	napi_disable(napi_tx); /* make sure current tx poll is done */
 
@@ -1711,6 +1706,9 @@ static int gve_xsk_wakeup(struct net_device *dev, u32 queue_id, u32 flags)
 	struct gve_priv *priv = netdev_priv(dev);
 	int tx_queue_id = gve_xdp_tx_queue_id(priv, queue_id);
 
+	if (!gve_get_napi_enabled(priv))
+		return -ENETDOWN;
+
 	if (queue_id >= priv->rx_cfg.num_queues || !priv->xdp_prog)
 		return -EINVAL;