[PATCH wireless-next] wifi: ath12k: allocate dummy net_device dynamically

[Breno Leitao]

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 ath12k_ext_irq_grp by converting it
into a pointer. Then use the leverage alloc_netdev_dummy() to allocate
the net_device object at ath12k_pci_ext_irq_config().

The free of the device occurs at ath12k_pci_free_ext_irq().

[1] https://lore.kernel.org/all/20240229225910.79e224cf@xxxxxxxxxx/

This is *very* similar to the same changes in ath11k commit
bca592ead82528b ("wifi: ath11k: allocate dummy net_device dynamically")

Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
---
 drivers/net/wireless/ath/ath12k/core.h |  2 +-
 drivers/net/wireless/ath/ath12k/pci.c  | 14 +++++++++++---
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/core.h b/drivers/net/wireless/ath/ath12k/core.h
index 97e5a0ccd233..71c67f47d0ad 100644
--- a/drivers/net/wireless/ath/ath12k/core.h
+++ b/drivers/net/wireless/ath/ath12k/core.h
@@ -144,7 +144,7 @@ struct ath12k_ext_irq_grp {
 	u32 grp_id;
 	u64 timestamp;
 	struct napi_struct napi;
-	struct net_device napi_ndev;
+	struct net_device *napi_ndev;
 };
 
 struct ath12k_smbios_bdf {
diff --git a/drivers/net/wireless/ath/ath12k/pci.c b/drivers/net/wireless/ath/ath12k/pci.c
index 14954bc05144..322f0ad1b12d 100644
--- a/drivers/net/wireless/ath/ath12k/pci.c
+++ b/drivers/net/wireless/ath/ath12k/pci.c
@@ -350,6 +350,7 @@ static void ath12k_pci_free_ext_irq(struct ath12k_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);
 	}
 }
 
@@ -560,7 +561,7 @@ static irqreturn_t ath12k_pci_ext_interrupt_handler(int irq, void *arg)
 static int ath12k_pci_ext_irq_config(struct ath12k_base *ab)
 {
 	struct ath12k_pci *ab_pci = ath12k_pci_priv(ab);
-	int i, j, ret, num_vectors = 0;
+	int i, j, n, ret, num_vectors = 0;
 	u32 user_base_data = 0, base_vector = 0, base_idx;
 
 	base_idx = ATH12K_PCI_IRQ_CE0_OFFSET + CE_COUNT_MAX;
@@ -577,8 +578,11 @@ static int ath12k_pci_ext_irq_config(struct ath12k_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,
 			       ath12k_pci_ext_grp_napi_poll);
 
 		if (ab->hw_params->ring_mask->tx[i] ||
@@ -611,6 +615,10 @@ static int ath12k_pci_ext_irq_config(struct ath12k_base *ab)
 			if (ret) {
 				ath12k_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;
 			}
 		}
-- 
2.43.0