Re: [PATCH net-next] IB/hfi1: allocate dummy net_device dynamically

[Dennis Dalessandro]

On 3/8/24 1:29 PM, Breno Leitao wrote:
> struct net_device shouldn't be embedded into any structure, instead,
> the owner should use the priv space to embed their state into net_device.
> 
> 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 iwl_trans_pcie by converting it
> into a pointer. Then use the leverage alloc_netdev() to allocate the
> net_device object at iwl_trans_pcie_alloc.

What does an Omni-Path Architecture driver from Cornelis Networks have to do
with an Intel wireless driver?

> The private data of net_device becomes a pointer for the struct
> iwl_trans_pcie, so, it is easy to get back to the iwl_trans_pcie parent
> given the net_device object.
> 
> [1] https://lore.kernel.org/all/20240229225910.79e224cf@xxxxxxxxxx/
> 
> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
> ---
>  drivers/infiniband/hw/hfi1/netdev.h    | 2 +-
>  drivers/infiniband/hw/hfi1/netdev_rx.c | 9 +++++++--
>  2 files changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/infiniband/hw/hfi1/netdev.h b/drivers/infiniband/hw/hfi1/netdev.h
> index 8aa074670a9c..07c8f77c9181 100644
> --- a/drivers/infiniband/hw/hfi1/netdev.h
> +++ b/drivers/infiniband/hw/hfi1/netdev.h
> @@ -49,7 +49,7 @@ struct hfi1_netdev_rxq {
>   *		When 0 receive queues will be freed.
>   */
>  struct hfi1_netdev_rx {
> -	struct net_device rx_napi;
> +	struct net_device *rx_napi;
>  	struct hfi1_devdata *dd;
>  	struct hfi1_netdev_rxq *rxq;
>  	int num_rx_q;
> diff --git a/drivers/infiniband/hw/hfi1/netdev_rx.c b/drivers/infiniband/hw/hfi1/netdev_rx.c
> index 720d4c85c9c9..5c26a69fa2bb 100644
> --- a/drivers/infiniband/hw/hfi1/netdev_rx.c
> +++ b/drivers/infiniband/hw/hfi1/netdev_rx.c
> @@ -188,7 +188,7 @@ static int hfi1_netdev_rxq_init(struct hfi1_netdev_rx *rx)
>  	int i;
>  	int rc;
>  	struct hfi1_devdata *dd = rx->dd;
> -	struct net_device *dev = &rx->rx_napi;
> +	struct net_device *dev = rx->rx_napi;
>  
>  	rx->num_rx_q = dd->num_netdev_contexts;
>  	rx->rxq = kcalloc_node(rx->num_rx_q, sizeof(*rx->rxq),
> @@ -360,7 +360,11 @@ int hfi1_alloc_rx(struct hfi1_devdata *dd)
>  	if (!rx)
>  		return -ENOMEM;
>  	rx->dd = dd;
> -	init_dummy_netdev(&rx->rx_napi);
> +	rx->rx_napi = alloc_netdev(sizeof(struct iwl_trans_pcie *),
> +				   "dummy", NET_NAME_UNKNOWN,
> +				   init_dummy_netdev);

Again with the iwl stuff? Please do not stuff to the mailing list that doesn't
even compile....

 CC [M]  drivers/infiniband/hw/hfi1/verbs.o
  CC [M]  drivers/infiniband/hw/hfi1/verbs_txreq.o
  CC [M]  drivers/infiniband/hw/hfi1/vnic_main.o
In file included from ./include/net/sock.h:46,
                 from ./include/linux/tcp.h:19,
                 from ./include/linux/ipv6.h:95,
                 from ./include/net/ipv6.h:12,
                 from ./include/rdma/ib_verbs.h:25,
                 from ./include/rdma/ib_hdrs.h:11,
                 from drivers/infiniband/hw/hfi1/hfi.h:29,
                 from drivers/infiniband/hw/hfi1/sdma.h:15,
                 from drivers/infiniband/hw/hfi1/netdev_rx.c:11:
drivers/infiniband/hw/hfi1/netdev_rx.c: In function ‘hfi1_alloc_rx’:
drivers/infiniband/hw/hfi1/netdev_rx.c:365:36: error: passing argument 4 of
‘alloc_netdev_mqs’ from incompatible pointer type
[-Werror=incompatible-pointer-types]
  365 |                                    init_dummy_netdev);
      |                                    ^~~~~~~~~~~~~~~~~
      |                                    |
      |                                    int (*)(struct net_device *)
/include/linux/netdevice.h:4632:63: note: in definition of macro ‘alloc_netdev’
 4632 |         alloc_netdev_mqs(sizeof_priv, name, name_assign_type, setup, 1, 1)
      |                                                               ^~~~~
/include/linux/netdevice.h:4629:44: note: expected ‘void (*)(struct net_device
*)’ but argument is of type ‘int (*)(struct net_device *)’
 4629 |                                     void (*setup)(struct net_device *),
      |                                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
  CC [M]  drivers/infiniband/hw/hfi1/vnic_sdma.o


Leon, please don't accept this until the author resubmits a patch that I either
Ack or Test.

Thanks

-Denny