crypto: caam: Unembed net_dev structure in dpaa2

Embedding net_device into structures prohibits the usage of flexible
arrays in the net_device structure. For more details, see the discussion
at [1].

Un-embed the net_devices from struct dpaa2_caam_priv_per_cpu by
converting them into pointers, and allocating them dynamically. Use the
leverage alloc_netdev_dummy() to allocate the net_device object at
dpaa2_dpseci_setup().

The free of the device occurs at dpaa2_dpseci_disable().

Link: https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/ [1]
Signed-off-by: Breno Leitao <leitao@debian.org>
Link: https://patch.msgid.link/20240702185557.3699991-5-leitao@debian.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/crypto/caam/caamalg_qi2.c

@@ -4990,11 +4990,23 @@ static int dpaa2_dpseci_congestion_setup(struct dpaa2_caam_priv *priv,
 	return err;
 }
 
+static void free_dpaa2_pcpu_netdev(struct dpaa2_caam_priv *priv, const cpumask_t *cpus)
+{
+	struct dpaa2_caam_priv_per_cpu *ppriv;
+	int i;
+
+	for_each_cpu(i, cpus) {
+		ppriv = per_cpu_ptr(priv->ppriv, i);
+		free_netdev(ppriv->net_dev);
+	}
+}
+
 static int __cold dpaa2_dpseci_setup(struct fsl_mc_device *ls_dev)
 {
 	struct device *dev = &ls_dev->dev;
 	struct dpaa2_caam_priv *priv;
 	struct dpaa2_caam_priv_per_cpu *ppriv;
+	cpumask_t clean_mask;
 	int err, cpu;
 	u8 i;
 
@@ -5073,6 +5085,7 @@ static int __cold dpaa2_dpseci_setup(struct fsl_mc_device *ls_dev)
 		}
 	}
 
+	cpumask_clear(&clean_mask);
 	i = 0;
 	for_each_online_cpu(cpu) {
 		u8 j;
@@ -5096,15 +5109,23 @@ static int __cold dpaa2_dpseci_setup(struct fsl_mc_device *ls_dev)
 			priv->rx_queue_attr[j].fqid,
 			priv->tx_queue_attr[j].fqid);
 
-		ppriv->net_dev.dev = *dev;
-		INIT_LIST_HEAD(&ppriv->net_dev.napi_list);
-		netif_napi_add_tx_weight(&ppriv->net_dev, &ppriv->napi,
+		ppriv->net_dev = alloc_netdev_dummy(0);
+		if (!ppriv->net_dev) {
+			err = -ENOMEM;
+			goto err_alloc_netdev;
+		}
+		cpumask_set_cpu(cpu, &clean_mask);
+		ppriv->net_dev->dev = *dev;
+
+		netif_napi_add_tx_weight(ppriv->net_dev, &ppriv->napi,
 					 dpaa2_dpseci_poll,
 					 DPAA2_CAAM_NAPI_WEIGHT);
 	}
 
 	return 0;
 
+err_alloc_netdev:
+	free_dpaa2_pcpu_netdev(priv, &clean_mask);
 err_get_rx_queue:
 	dpaa2_dpseci_congestion_free(priv);
 err_get_vers:
@@ -5153,6 +5174,7 @@ static int __cold dpaa2_dpseci_disable(struct dpaa2_caam_priv *priv)
 		ppriv = per_cpu_ptr(priv->ppriv, i);
 		napi_disable(&ppriv->napi);
 		netif_napi_del(&ppriv->napi);
+		free_netdev(ppriv->net_dev);
 	}
 
 	return 0;

drivers/crypto/caam/caamalg_qi2.h

@@ -81,7 +81,7 @@ struct dpaa2_caam_priv {
  */
 struct dpaa2_caam_priv_per_cpu {
 	struct napi_struct napi;
-	struct net_device net_dev;
+	struct net_device *net_dev;
 	int req_fqid;
 	int rsp_fqid;
 	int prio;