Re: [PATCH] ath10k: allocate dummy net_device dynamically

[Jeff Johnson <quic_jjohnson@quicinc.com>]

On 3/19/2024 3:47 AM, Breno Leitao wrote:
> 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 ath10k by converting it
> into a pointer. Then use the leverage alloc_netdev() to allocate the
> net_device object at ath10k_core_create(). The free of the device occurs
> at ath10k_core_destroy().
> 
> [1] https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/
> 
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
>  drivers/net/wireless/ath/ath10k/core.c | 10 ++++++++--
>  drivers/net/wireless/ath/ath10k/core.h |  2 +-
>  drivers/net/wireless/ath/ath10k/pci.c  |  2 +-
>  drivers/net/wireless/ath/ath10k/sdio.c |  2 +-
>  drivers/net/wireless/ath/ath10k/snoc.c |  4 ++--
>  drivers/net/wireless/ath/ath10k/usb.c  |  2 +-
>  6 files changed, 14 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath10k/core.c b/drivers/net/wireless/ath/ath10k/core.c
> index 9ce6f49ab261..3736517002f6 100644
> --- a/drivers/net/wireless/ath/ath10k/core.c
> +++ b/drivers/net/wireless/ath/ath10k/core.c
> @@ -3673,11 +3673,14 @@ struct ath10k *ath10k_core_create(size_t priv_size, struct device *dev,
>  	INIT_WORK(&ar->set_coverage_class_work,
>  		  ath10k_core_set_coverage_class_work);
>  
> -	init_dummy_netdev(&ar->napi_dev);
> +	ar->napi_dev = alloc_netdev(0, "dummy", NET_NAME_UNKNOWN,
> +				    init_dummy_netdev);
> +	if (!ar->napi_dev)
> +		goto err_free_tx_complete;
>  
>  	ret = ath10k_coredump_create(ar);
>  	if (ret)
> -		goto err_free_tx_complete;
> +		goto err_free_netdev;
>  
>  	ret = ath10k_debug_create(ar);
>  	if (ret)
> @@ -3687,6 +3690,8 @@ struct ath10k *ath10k_core_create(size_t priv_size, struct device *dev,
>  
>  err_free_coredump:
>  	ath10k_coredump_destroy(ar);
> +err_free_netdev:
> +	free_netdev(ar->napi_dev);
>  err_free_tx_complete:
>  	destroy_workqueue(ar->workqueue_tx_complete);
>  err_free_aux_wq:
> @@ -3708,6 +3713,7 @@ void ath10k_core_destroy(struct ath10k *ar)
>  
>  	destroy_workqueue(ar->workqueue_tx_complete);
>  
> +	free_netdev(ar->napi_dev);
>  	ath10k_debug_destroy(ar);
>  	ath10k_coredump_destroy(ar);
>  	ath10k_htt_tx_destroy(&ar->htt);

looks like there is a pre-existing issue that the order of operations in
_destroy() doesn't match the order of operations in the _create() error path.

but the placement of your changes looks ok to me


> diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
> index c110d15528bd..26003b519574 100644
> --- a/drivers/net/wireless/ath/ath10k/core.h
> +++ b/drivers/net/wireless/ath/ath10k/core.h
> @@ -1269,7 +1269,7 @@ struct ath10k {
>  	struct ath10k_per_peer_tx_stats peer_tx_stats;
>  
>  	/* NAPI */
> -	struct net_device napi_dev;
> +	struct net_device *napi_dev;
>  	struct napi_struct napi;
>  
>  	struct work_struct set_coverage_class_work;
> diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
> index 5c34b156b4ff..558bec96ae40 100644
> --- a/drivers/net/wireless/ath/ath10k/pci.c
> +++ b/drivers/net/wireless/ath/ath10k/pci.c
> @@ -3217,7 +3217,7 @@ static void ath10k_pci_free_irq(struct ath10k *ar)
>  
>  void ath10k_pci_init_napi(struct ath10k *ar)
>  {
> -	netif_napi_add(&ar->napi_dev, &ar->napi, ath10k_pci_napi_poll);
> +	netif_napi_add(ar->napi_dev, &ar->napi, ath10k_pci_napi_poll);
>  }
>  
>  static int ath10k_pci_init_irq(struct ath10k *ar)
> diff --git a/drivers/net/wireless/ath/ath10k/sdio.c b/drivers/net/wireless/ath/ath10k/sdio.c
> index 0ab5433f6cf6..e28f2fe1101b 100644
> --- a/drivers/net/wireless/ath/ath10k/sdio.c
> +++ b/drivers/net/wireless/ath/ath10k/sdio.c
> @@ -2532,7 +2532,7 @@ static int ath10k_sdio_probe(struct sdio_func *func,
>  		return -ENOMEM;
>  	}
>  
> -	netif_napi_add(&ar->napi_dev, &ar->napi, ath10k_sdio_napi_poll);
> +	netif_napi_add(ar->napi_dev, &ar->napi, ath10k_sdio_napi_poll);
>  
>  	ath10k_dbg(ar, ATH10K_DBG_BOOT,
>  		   "sdio new func %d vendor 0x%x device 0x%x block 0x%x/0x%x\n",
> diff --git a/drivers/net/wireless/ath/ath10k/snoc.c b/drivers/net/wireless/ath/ath10k/snoc.c
> index 2c39bad7ebfb..0449b9ffc32d 100644
> --- a/drivers/net/wireless/ath/ath10k/snoc.c
> +++ b/drivers/net/wireless/ath/ath10k/snoc.c
> @@ -935,7 +935,7 @@ static int ath10k_snoc_hif_start(struct ath10k *ar)
>  
>  	bitmap_clear(ar_snoc->pending_ce_irqs, 0, CE_COUNT_MAX);
>  
> -	dev_set_threaded(&ar->napi_dev, true);
> +	dev_set_threaded(ar->napi_dev, true);
>  	ath10k_core_napi_enable(ar);
>  	ath10k_snoc_irq_enable(ar);
>  	ath10k_snoc_rx_post(ar);
> @@ -1253,7 +1253,7 @@ static int ath10k_snoc_napi_poll(struct napi_struct *ctx, int budget)
>  
>  static void ath10k_snoc_init_napi(struct ath10k *ar)
>  {
> -	netif_napi_add(&ar->napi_dev, &ar->napi, ath10k_snoc_napi_poll);
> +	netif_napi_add(ar->napi_dev, &ar->napi, ath10k_snoc_napi_poll);
>  }
>  
>  static int ath10k_snoc_request_irq(struct ath10k *ar)
> diff --git a/drivers/net/wireless/ath/ath10k/usb.c b/drivers/net/wireless/ath/ath10k/usb.c
> index 3c482baacec1..3b51b7f52130 100644
> --- a/drivers/net/wireless/ath/ath10k/usb.c
> +++ b/drivers/net/wireless/ath/ath10k/usb.c
> @@ -1014,7 +1014,7 @@ static int ath10k_usb_probe(struct usb_interface *interface,
>  		return -ENOMEM;
>  	}
>  
> -	netif_napi_add(&ar->napi_dev, &ar->napi, ath10k_usb_napi_poll);
> +	netif_napi_add(ar->napi_dev, &ar->napi, ath10k_usb_napi_poll);
>  
>  	usb_get_dev(dev);
>  	vendor_id = le16_to_cpu(dev->descriptor.idVendor);

I've pinged the development team to see if they can validate this on hardware
-- I don't have any ath10k setups.

Will ack this once I get confirmation.

/jeff