RE: [EXTERNAL] [PATCH net-next v3 2/5] net: marvell: prestera: allocate dummy net_device dynamically

[Elad Nachman]

> -----Original Message-----
> From: Breno Leitao <leitao@xxxxxxxxxx>
> Sent: Thursday, April 4, 2024 2:49 PM
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> pabeni@xxxxxxxxxx; edumazet@xxxxxxxxxx; elder@xxxxxxxxxx; linux-arm-
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> Subject: [EXTERNAL] [PATCH net-next v3 2/5] net: marvell: prestera: allocate
> dummy net_device dynamically
> 
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> 
> ----------------------------------------------------------------------
> 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://urldefense.proofpoint.com/v2/url?u=https-
> 3A__lore.kernel.org_all_20240229225910.79e224cf-
> 40kernel.org_&d=DwIDAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=eTeNTLEK5-
> TxXczjOcKPhANIFtlB9pP4lq9qhdlFrwQ&m=8Fqw_UUg1WoXjQcCjAtMa9J6QAd
> lmUzCuk3nWriMXtYMbgBqNpdDSO4rBUanJDxw&s=lXBodHe9jPOjWAOTFCjnZ
> 2ZDZYoF79OGsWN38gbxhTE&e=
> 
> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
> ---
>  .../net/ethernet/marvell/prestera/prestera_rxtx.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/marvell/prestera/prestera_rxtx.c
> b/drivers/net/ethernet/marvell/prestera/prestera_rxtx.c
> index cc2a9ae794be..39d9bf82c115 100644
> --- a/drivers/net/ethernet/marvell/prestera/prestera_rxtx.c
> +++ b/drivers/net/ethernet/marvell/prestera/prestera_rxtx.c
> @@ -96,7 +96,7 @@ struct prestera_sdma {
>  	struct dma_pool *desc_pool;
>  	struct work_struct tx_work;
>  	struct napi_struct rx_napi;
> -	struct net_device napi_dev;
> +	struct net_device *napi_dev;
>  	u32 map_addr;
>  	u64 dma_mask;
>  	/* protect SDMA with concurrent access from multiple CPUs */ @@ -
> 654,13 +654,21 @@ static int prestera_sdma_switch_init(struct
> prestera_switch *sw)
>  	if (err)
>  		goto err_evt_register;
> 
> -	init_dummy_netdev(&sdma->napi_dev);
> +	sdma->napi_dev = alloc_netdev_dummy(0);
> +	if (!sdma->napi_dev) {
> +		dev_err(dev, "not able to initialize dummy device\n");
> +		err = -ENOMEM;
> +		goto err_alloc_dummy;
> +	}
> 
> -	netif_napi_add(&sdma->napi_dev, &sdma->rx_napi,
> prestera_sdma_rx_poll);
> +	netif_napi_add(sdma->napi_dev, &sdma->rx_napi,
> prestera_sdma_rx_poll);
>  	napi_enable(&sdma->rx_napi);
> 
>  	return 0;
> 
> +err_alloc_dummy:
> +	prestera_hw_event_handler_unregister(sw,
> PRESTERA_EVENT_TYPE_RXTX,
> +					     prestera_rxtx_handle_event);
>  err_evt_register:
>  err_tx_init:
>  	prestera_sdma_tx_fini(sdma);
> @@ -677,6 +685,7 @@ static void prestera_sdma_switch_fini(struct
> prestera_switch *sw)
> 
>  	napi_disable(&sdma->rx_napi);
>  	netif_napi_del(&sdma->rx_napi);
> +	free_netdev(sdma->napi_dev);
>  	prestera_hw_event_handler_unregister(sw,
> PRESTERA_EVENT_TYPE_RXTX,
>  					     prestera_rxtx_handle_event);
>  	prestera_sdma_tx_fini(sdma);
> --
> 2.43.0
> 

Acked-by: Elad Nachman <enachman@xxxxxxxxxxx>