Re: [PATCH wireless-next] wifi: ath12k: allocate dummy net_device dynamically

Breno Leitao
2024-05-07T11:47:56Z

On Sat, May 04, 2024 at 03:55:23PM +0100, Simon Horman wrote:
> On Fri, May 03, 2024 at 03:04:39AM -0700, 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 ath12k_ext_irq_grp by converting it
> > into a pointer. Then use the leverage alloc_netdev_dummy() to allocate
> > the net_device object at ath12k_pci_ext_irq_config().
> >
> > The free of the device occurs at ath12k_pci_free_ext_irq().
> >
> > [1] https://lore.kernel.org/all/20240229225910.79e224cf@kernel.org/
> >
> > This is *very* similar to the same changes in ath11k commit
> > bca592ead82528b ("wifi: ath11k: allocate dummy net_device dynamically")
> >
> > Signed-off-by: Breno Leitao <leitao@debian.org>
>
> ...
>
> > diff --git a/drivers/net/wireless/ath/ath12k/pci.c b/drivers/net/wireless/ath/ath12k/pci.c
>
> ...
>
> > @@ -577,8 +578,11 @@ static int ath12k_pci_ext_irq_config(struct ath12k_base *ab)
> >
> > irq_grp->ab = ab;
> > irq_grp->grp_id = i;
> > - init_dummy_netdev(&irq_grp->napi_ndev);
> > - netif_napi_add(&irq_grp->napi_ndev, &irq_grp->napi,
> > + irq_grp->napi_ndev = alloc_netdev_dummy(0);
> > + if (!irq_grp->napi_ndev)
> > + return -ENOMEM;
>
> Hi Breno,
>
> Will returning on error here leak resources allocated by
> alloc_netdev_dummy() in previous iterations of this loop?

very good catch. Thanks!

> If so, I suggest jumping to unwind handling which
> can be shared with the error path in the hunk below.

Agree. let me spend some time and propose a V2.

Thanks