Re: [PATCH net-next v1] net: devmem: NULL check netdev_nl_get_dma_dev return value

[Mina Almasry <almasrymina@google.com>]

On Tue, Sep 2, 2025 at 8:54 AM Stanislav Fomichev <stfomichev@gmail.com> wrote:
>
> On 08/29, Jakub Kicinski wrote:
> > On Fri, 29 Aug 2025 21:59:38 +0000 Mina Almasry wrote:
> > > netdev_nl_get_dma_dev can return NULL. This happens in the unlikely
> > > scenario that netdev->dev.parent is NULL, or all the calls to the
> > > ndo_queue_get_dma_dev return NULL from the driver.
> >
> > I probably have Friday brain but I don't see what you mean..
> > In net-next net_devmem_bind_dmabuf() gets a dma_dev and returns
> > -EOPNOTSUPP PTR if its NULL.
>
> +1, the description and the fix are confusing.
>
> Unless I'm missing something, the intent seems to be to avoid hitting
> a WARN_ON in dma_buf_attach (really dma_buf_dynamic_attach) when the dma_dev
> is NULL. Mina, can we do this in the callers of netdev_queue_get_dma_dev?

Yes looks like I was the one with the Friday brain. I missed the NULL
check in net_devmem_bind_dmabuf. I'll check if this issue is on net
and send a fix there if needed.

-- 
Thanks,
Mina