Re: [PATCH] xen/pci: replace call to is_memory_hole to pci_check_bar

[Julien Grall <julien@xxxxxxx>]

Hi Rahul,

This patch seems to have been sent in-reply-to the SMMUv1 patch. Was it 
intended?
On 09/08/2022 16:22, Rahul Singh wrote:
> > On 8 Aug 2022, at 4:30 pm, Oleksandr <olekstysh@xxxxxxxxx> wrote:
> > > +bool pci_check_bar(const struct pci_dev *pdev, mfn_t start, mfn_t end)
> > > +{
> > > +    int ret;
> > > +    struct dt_device_node *dt_node;
> > > +    struct device *dev = (struct device *)pci_to_dev(pdev);
> >
> > The cast is present here because of the const?
> Yes you are right, cast is because of the const.
> > I would consider passing "const struct pci_dev *pdev" instead of "struct device *dev" 
> > to pci_find_host_bridge_node() and dropping conversion (pci<->dev) in both functions.
It looks like this function was added without any callers. The commit 
message claim there will be some. Can you (or Oleksandr) confirm this is 
not going to be problem for future patches?
That said, I agree that the conversion pci -> dev -> pci is pointless. 
So I would say if there are use case where we only have a 'dev' in hand, 
then we could ask the caller to do the conversation or we provide an 
helper if there are too many cases.
> Yes make sense. I will do that in next version.
While you are modifying the prototype for pci_find_host_bridge_node() 
can you consider to also constify the return (it should not be modified)?
In any case, the change suggested by Oleksandr should preferably be 
separate to this patch and added before.
Cheers,

--
Julien Grall