[PATCH net-next v5 05/10] net: mediatek: mtk_eth_sock: allocate dummy net_device dynamically

Breno Leitao
2024-04-10T13:19:09Z

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 the private struct by converting it
into a pointer. Then use the leverage the new alloc_netdev_dummy()
helper to allocate and initialize dummy devices.

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

Signed-off-by: Breno Leitao <leitao@debian.org>
---
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 17 +++++++++++++----
drivers/net/ethernet/mediatek/mtk_eth_soc.h | 2 +-
2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index caa13b9cedff..d7a96dc11c07 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -1710,7 +1710,7 @@ static struct page_pool *mtk_create_page_pool(struct mtk_eth *eth,
if (IS_ERR(pp))
return pp;

- err = __xdp_rxq_info_reg(xdp_q, &eth->dummy_dev, id,
+ err = __xdp_rxq_info_reg(xdp_q, eth->dummy_dev, id,
eth->rx_napi.napi_id, PAGE_SIZE);
if (err < 0)
goto err_free_pp;
@@ -4188,6 +4188,8 @@ static int mtk_free_dev(struct mtk_eth *eth)
metadata_dst_free(eth->dsa_meta[i]);
}

+ free_netdev(eth->dummy_dev);
+
return 0;
}

@@ -4983,9 +4985,14 @@ static int mtk_probe(struct platform_device *pdev)
/* we run 2 devices on the same DMA ring so we need a dummy device
* for NAPI to work
*/
- init_dummy_netdev(&eth->dummy_dev);
- netif_napi_add(&eth->dummy_dev, &eth->tx_napi, mtk_napi_tx);
- netif_napi_add(&eth->dummy_dev, &eth->rx_napi, mtk_napi_rx);
+ eth->dummy_dev = alloc_netdev_dummy(0);
+ if (!eth->dummy_dev) {
+ err = -ENOMEM;
+ dev_err(eth->dev, "failed to allocated dummy device\n");
+ goto err_unreg_netdev;
+ }
+ netif_napi_add(eth->dummy_dev, &eth->tx_napi, mtk_napi_tx);
+ netif_napi_add(eth->dummy_dev, &eth->rx_napi, mtk_napi_rx);

platform_set_drvdata(pdev, eth);
schedule_delayed_work(&eth->reset.monitor_work,
@@ -4993,6 +5000,8 @@ static int mtk_probe(struct platform_device *pdev)

return 0;

+err_unreg_netdev:
+ mtk_unreg_dev(eth);
err_deinit_ppe:
mtk_ppe_deinit(eth);
mtk_mdio_cleanup(eth);
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index 9ae3b8a71d0e..723fc637027c 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -1242,7 +1242,7 @@ struct mtk_eth {
spinlock_t page_lock;
spinlock_t tx_irq_lock;
spinlock_t rx_irq_lock;
- struct net_device dummy_dev;
+ struct net_device *dummy_dev;
struct net_device *netdev[MTK_MAX_DEVS];
struct mtk_mac *mac[MTK_MAX_DEVS];
int irq[3];
--
2.43.0