Subject: Re: [PATCH net-next] net: ethernet: mtk_wed: do not assume offload callbacks are always set

From: Lorenzo Bianconi <[email-masked]>
Date: Tue, 12 Sep 2023 22:31:06 +0200

> On Tue, Sep 12, 2023 at 10:26:07AM +0200, Lorenzo Bianconi wrote:
> > Check if wlan.offload_enable and wlan.offload_disable callbacks are set
> > in mtk_wed_flow_add/mtk_wed_flow_remove since mt7996 will not rely
> > on them.
> > 
> > Signed-off-by: Lorenzo Bianconi <[email-masked]>
> 
> Hi Lorenzo,
> 
> It's not not a big deal from my perspective, but
> I do wonder if these mediatek patches could have been a series.
> 
> > ---
> >  drivers/net/ethernet/mediatek/mtk_wed.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/drivers/net/ethernet/mediatek/mtk_wed.c b/drivers/net/ethernet/mediatek/mtk_wed.c
> > index 94376aa2b34c..d8cd59f44401 100644
> > --- a/drivers/net/ethernet/mediatek/mtk_wed.c
> > +++ b/drivers/net/ethernet/mediatek/mtk_wed.c
> > @@ -1718,6 +1718,9 @@ int mtk_wed_flow_add(int index)
> >  	if (!hw || !hw->wed_dev)
> >  		return -ENODEV;
> >  
> > +	if (!hw->wed_dev->wlan.offload_enable)
> > +		return 0;
> 
> A little further down in this function it is assumed that hw->wed_dev may
> be NULL, a check made under a lock no less. But it is dereferenced
> unconditionally here without a lock. This doesn't seem right one way or
> another.
> 
> As flagged by Smatch.

Hi Simon,

you are right. I will fix it in v2.

Regards,
Lorenzo

> 
> > +
> >  	if (hw->num_flows) {
> >  		hw->num_flows++;
> >  		return 0;
> > @@ -1747,6 +1750,9 @@ void mtk_wed_flow_remove(int index)
> >  	if (!hw)
> >  		return;
> >  
> > +	if (!hw->wed_dev->wlan.offload_disable)
> > +		return;
> > +
> >  	if (--hw->num_flows)
> >  		return;
> >  
> > -- 
> > 2.41.0
> > 
> >