wifi: ath11k: allocate dummy net_device dynamically

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_device from struct ath11k_ext_irq_grp by converting it
into a pointer. Then use the leverage alloc_netdev() to allocate the
net_device object at ath11k_ahb_config_ext_irq() for ahb, and
ath11k_pcic_ext_irq_config() for pcic.

The free of the device occurs at ath11k_ahb_free_ext_irq() for the ahb
case, and ath11k_pcic_free_ext_irq() for the pcic case.

[1] https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/Signed-off-by: Breno Leitao <leitao@debian.org>
Tested-by: Kalle Valo <kvalo@kernel.org>
Acked-by: Kalle Valo <kvalo@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/wireless/ath/ath11k/ahb.c

@@ -442,6 +442,7 @@ static void ath11k_ahb_free_ext_irq(struct ath11k_base *ab)
 			free_irq(ab->irq_num[irq_grp->irqs[j]], irq_grp);
 
 		netif_napi_del(&irq_grp->napi);
+		free_netdev(irq_grp->napi_ndev);
 	}
 }
 
@@ -533,8 +534,12 @@ static int ath11k_ahb_config_ext_irq(struct ath11k_base *ab)
 
 		irq_grp->ab = ab;
 		irq_grp->grp_id = i;
-		init_dummy_netdev(&irq_grp->napi_ndev);
-		netif_napi_add(&irq_grp->napi_ndev, &irq_grp->napi,
+
+		irq_grp->napi_ndev = alloc_netdev_dummy(0);
+		if (!irq_grp->napi_ndev)
+			return -ENOMEM;
+
+		netif_napi_add(irq_grp->napi_ndev, &irq_grp->napi,
 			       ath11k_ahb_ext_grp_napi_poll);
 
 		for (j = 0; j < ATH11K_EXT_IRQ_NUM_MAX; j++) {

drivers/net/wireless/ath/ath11k/core.h

@@ -174,7 +174,7 @@ struct ath11k_ext_irq_grp {
 	u64 timestamp;
 	bool napi_enabled;
 	struct napi_struct napi;
-	struct net_device napi_ndev;
+	struct net_device *napi_ndev;
 };
 
 enum ath11k_smbios_cc_type {

drivers/net/wireless/ath/ath11k/pcic.c

@@ -316,6 +316,7 @@ static void ath11k_pcic_free_ext_irq(struct ath11k_base *ab)
 			free_irq(ab->irq_num[irq_grp->irqs[j]], irq_grp);
 
 		netif_napi_del(&irq_grp->napi);
+		free_netdev(irq_grp->napi_ndev);
 	}
 }
 
@@ -558,7 +559,7 @@ ath11k_pcic_get_msi_irq(struct ath11k_base *ab, unsigned int vector)
 
 static int ath11k_pcic_ext_irq_config(struct ath11k_base *ab)
 {
-	int i, j, ret, num_vectors = 0;
+	int i, j, n, ret, num_vectors = 0;
 	u32 user_base_data = 0, base_vector = 0;
 	unsigned long irq_flags;
 
@@ -578,8 +579,11 @@ static int ath11k_pcic_ext_irq_config(struct ath11k_base *ab)
 
 		irq_grp->ab = ab;
 		irq_grp->grp_id = i;
-		init_dummy_netdev(&irq_grp->napi_ndev);
-		netif_napi_add(&irq_grp->napi_ndev, &irq_grp->napi,
+		irq_grp->napi_ndev = alloc_netdev_dummy(0);
+		if (!irq_grp->napi_ndev)
+			return -ENOMEM;
+
+		netif_napi_add(irq_grp->napi_ndev, &irq_grp->napi,
 			       ath11k_pcic_ext_grp_napi_poll);
 
 		if (ab->hw_params.ring_mask->tx[i] ||
@@ -601,8 +605,13 @@ static int ath11k_pcic_ext_irq_config(struct ath11k_base *ab)
 			int vector = (i % num_vectors) + base_vector;
 			int irq = ath11k_pcic_get_msi_irq(ab, vector);
 
-			if (irq < 0)
+			if (irq < 0) {
+				for (n = 0; n <= i; n++) {
+					irq_grp = &ab->ext_irq_grp[n];
+					free_netdev(irq_grp->napi_ndev);
+				}
 				return irq;
+			}
 
 			ab->irq_num[irq_idx] = irq;
 
@@ -615,6 +624,10 @@ static int ath11k_pcic_ext_irq_config(struct ath11k_base *ab)
 			if (ret) {
 				ath11k_err(ab, "failed request irq %d: %d\n",
 					   vector, ret);
+				for (n = 0; n <= i; n++) {
+					irq_grp = &ab->ext_irq_grp[n];
+					free_netdev(irq_grp->napi_ndev);
+				}
 				return ret;
 			}
 		}