Re: [PATCH v4 2/3] PCI: dwc: ep: Add per-PF BAR and inbound ATU mapping support

[Aksh Garg]

On 30/01/26 16:17, Niklas Cassel wrote:
> On Fri, Jan 30, 2026 at 04:09:26PM +0530, Aksh Garg wrote:
> > On 30/01/26 15:23, Niklas Cassel wrote:
> > > On Fri, Jan 30, 2026 at 09:42:43AM +0530, Aksh Garg wrote:
> > > > On 29/01/26 19:44, Niklas Cassel wrote:
> > > > > On Thu, Jan 29, 2026 at 02:47:52PM +0530, Aksh Garg wrote:
> > > > > > -static void dw_pcie_ep_clear_ib_maps(struct dw_pcie_ep *ep, enum pci_barno bar)
> > > > > > +static void dw_pcie_ep_clear_ib_maps(struct dw_pcie_ep *ep, u8 func_no, enum pci_barno bar)
> > > > > >  {
> > > > > > +	struct dw_pcie_ep_func *ep_func = dw_pcie_ep_get_func_from_ep(ep, func_no);
> > > > > >  	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> > > > > >  	struct device *dev = pci->dev;
> > > > > >  	unsigned int i, num;
> > > > > > @@ -152,18 +157,18 @@ static void dw_pcie_ep_clear_ib_maps(struct dw_pcie_ep *ep, enum pci_barno bar)
> > > > > >  	u32 *indexes;
> > > > > > Hello Aksh,
> > > > > > Considering that all other functions that you have modified, you
> > > > have added a:
> > > > > > if (!ep_func)
> > > > > 	return;
> > > > > > > I think you should do the same to this function.
> > > > >
> > > > 
> > > > I omitted this NULL check here because all the current call sites of
> > > > dw_pcie_ep_clear_ib_maps() already perform this validation. I felt
> > > > adding it here would add redundancy in the code.
> > > 
> > > Ok, but with that logic, shouldn't we also remove the NULL checks from
> > > dw_pcie_ep_ib_atu_bar() and dw_pcie_ep_ib_atu_addr(), because they are
> > > only called from dw_pcie_ep_set_bar(), which already has the ep_func
> > > NULL check?
> > > 
> >
> > Yes, that's correct. Alternatively, we can add the NULL check in
> > dw_pcie_ep_clear_ib_maps() as well, making all the functions using
> > ep_func self-contained and defensive, removing the dependency on whether
> > the callers perform NULL checks. This makes the code more future proof,
> > as new callers won't need to be aware of the NULL pointer possibility.
>
> Sounds like a good idea to me.
>
> Neither of these functions is in the hot path, so the performance of having
> one less NULL check is not super critical.

Okay, I will post a new patch series adding the NULL check in the
function.

Regards,
Aksh Garg

> Kind regards,
> Niklas