netdev - [PATCH wireless-next] wil6210: Do not use embedded netdev in wil6210

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Date: Fri,  3 May 2024 03:32:56 -0700
From: Breno Leitao <leitao@...ian.org>
To: Kalle Valo <kvalo@...nel.org>
Cc: netdev@...r.kernel.org,
	merez@...eaurora.org,
	quic_ailizaro@...cinc.com,
	linux-wireless@...r.kernel.org (open list:WILOCITY WIL6210 WIRELESS DRIVER),
	linux-kernel@...r.kernel.org (open list)
Subject: [PATCH wireless-next] wil6210: Do not use embedded netdev in wil6210_priv

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 wil6210_priv by converting it
into a pointer. Then use the leverage alloc_netdev_dummy() to allocate
the net_device object at wil_if_add(). The free of the device
occurs at wil_if_remove().

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

Signed-off-by: Breno Leitao <leitao@...ian.org>
---
 drivers/net/wireless/ath/wil6210/netdev.c  | 21 +++++++++++++++------
 drivers/net/wireless/ath/wil6210/wil6210.h |  2 +-
 2 files changed, 16 insertions(+), 7 deletions(-)

PS: I only compile-tested this patch due to lack of hardware.

diff --git a/drivers/net/wireless/ath/wil6210/netdev.c b/drivers/net/wireless/ath/wil6210/netdev.c
index ee7d7e9c2718..d5d364683c0e 100644
--- a/drivers/net/wireless/ath/wil6210/netdev.c
+++ b/drivers/net/wireless/ath/wil6210/netdev.c
@@ -453,16 +453,21 @@ int wil_if_add(struct wil6210_priv *wil)
 		return rc;
 	}
 
-	init_dummy_netdev(&wil->napi_ndev);
+	wil->napi_ndev = alloc_netdev_dummy(0);
+	if (!wil->napi_ndev) {
+		wil_err(wil, "failed to allocate dummy netdev");
+		rc = -ENOMEM;
+		goto out_wiphy;
+	}
 	if (wil->use_enhanced_dma_hw) {
-		netif_napi_add(&wil->napi_ndev, &wil->napi_rx,
+		netif_napi_add(wil->napi_ndev, &wil->napi_rx,
 			       wil6210_netdev_poll_rx_edma);
-		netif_napi_add_tx(&wil->napi_ndev,
+		netif_napi_add_tx(wil->napi_ndev,
 				  &wil->napi_tx, wil6210_netdev_poll_tx_edma);
 	} else {
-		netif_napi_add(&wil->napi_ndev, &wil->napi_rx,
+		netif_napi_add(wil->napi_ndev, &wil->napi_rx,
 			       wil6210_netdev_poll_rx);
-		netif_napi_add_tx(&wil->napi_ndev,
+		netif_napi_add_tx(wil->napi_ndev,
 				  &wil->napi_tx, wil6210_netdev_poll_tx);
 	}
 
@@ -474,10 +479,12 @@ int wil_if_add(struct wil6210_priv *wil)
 	wiphy_unlock(wiphy);
 	rtnl_unlock();
 	if (rc < 0)
-		goto out_wiphy;
+		goto free_dummy;
 
 	return 0;
 
+free_dummy:
+	free_netdev(wil->napi_ndev);
 out_wiphy:
 	wiphy_unregister(wiphy);
 	return rc;
@@ -554,5 +561,7 @@ void wil_if_remove(struct wil6210_priv *wil)
 	netif_napi_del(&wil->napi_tx);
 	netif_napi_del(&wil->napi_rx);
 
+	free_netdev(wil->napi_ndev);
+
 	wiphy_unregister(wiphy);
 }
diff --git a/drivers/net/wireless/ath/wil6210/wil6210.h b/drivers/net/wireless/ath/wil6210/wil6210.h
index 22a6eb3e12b7..9bd1286d2857 100644
--- a/drivers/net/wireless/ath/wil6210/wil6210.h
+++ b/drivers/net/wireless/ath/wil6210/wil6210.h
@@ -983,7 +983,7 @@ struct wil6210_priv {
 	spinlock_t eap_lock; /* guarding access to eap rekey fields */
 	struct napi_struct napi_rx;
 	struct napi_struct napi_tx;
-	struct net_device napi_ndev; /* dummy net_device serving all VIFs */
+	struct net_device *napi_ndev; /* dummy net_device serving all VIFs */
 
 	/* DMA related */
 	struct wil_ring ring_rx;
-- 
2.43.0