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

Dennis Dalessandro
2024-03-11T22:22:15Z

On 3/11/24 11:32 AM, Breno Leitao wrote:
> Hello Dennis,
>
> On Mon, Mar 11, 2024 at 08:05:45AM -0400, Dennis Dalessandro wrote:
>> 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?
>
> That is an oversight. I will fix it in v2. Sorry about it.
>
>>> 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@kernel.org/
>>>
>>> Signed-off-by: Breno Leitao <leitao@debian.org>
>>> ---
>>> 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
>
> Sorry, this patch is against net-next and you probably tested in Linus'
> upstream.
>
> You need to have d160c66cda0ac8614 ("net: Do not return value from
> init_dummy_netdev()"), which is in net-next, and has this important
> change that is necessary for this patch:
>
> -int init_dummy_netdev(struct net_device *dev);
> +void init_dummy_netdev(struct net_device *dev);
>
> If you are OK with a v2, I will fix the topics reported in this thread.

You also use struct iwl_trans_pcie in hfi1 code. Fix that up, and make sure the
patch builds and I'll give it a test.

-Denny

> Thank you
> Breno