Re: [RFC v5 2/7] PCI: Do not Use IORESOURCE_STARTALIGN to identify bridge resources

[Yongji Xie]

On 2016/4/6 8:55, Gavin Shan wrote:
> On Tue, Apr 05, 2016 at 09:43:30PM +0800, Yongji Xie wrote:
> > Now we use the IORESOURCE_STARTALIGN to identify
> > bridge resources in __assign_resources_sorted().
> > That's quite fragile. We can't make sure that
> > the PCI devices' resources will not use
> > IORESOURCE_STARTALIGN any more.
> >
> > In this patch, we try to use a more robust way
> > to identify bridge resources.
> >
> > Signed-off-by: Yongji Xie <xyjxie@xxxxxxxxxxxxxxxxxx>
> > ---
> > drivers/pci/setup-bus.c |   10 +++++++---
> > 1 file changed, 7 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> > index 7796d0a..bffcf1e 100644
> > --- a/drivers/pci/setup-bus.c
> > +++ b/drivers/pci/setup-bus.c
> > @@ -391,6 +391,7 @@ static void __assign_resources_sorted(struct list_head *head,
> > 	struct pci_dev_resource *dev_res, *tmp_res, *dev_res2;
> > 	unsigned long fail_type;
> > 	resource_size_t add_align, align;
> > +	int index;
> >
> > 	/* Check if optional add_size is there */
> > 	if (!realloc_head || list_empty(realloc_head))
> > @@ -411,11 +412,14 @@ static void __assign_resources_sorted(struct list_head *head,
> >
> > 		/*
> > 		 * There are two kinds of additional resources in the list:
> > -		 * 1. bridge resource  -- IORESOURCE_STARTALIGN
> > -		 * 2. SR-IOV resource   -- IORESOURCE_SIZEALIGN
> > +		 * 1. bridge resource
> > +		 * 2. SR-IOV resource
> > 		 * Here just fix the additional alignment for bridge
> > 		 */
> > -		if (!(dev_res->res->flags & IORESOURCE_STARTALIGN))
> > +		index = dev_res->res - dev_res->dev->resource;
> > +		if (pci_is_bridge(dev_res->dev) &&
> > +			index >= PCI_BRIDGE_RESOURCES &&
> > +			index <= PCI_BRIDGE_RESOURCE_END)
> > 			continue;
> Yongji, the condition seems incorrect. According to the comments in
> the code, it's resizing bridge's windows. So I think the code would
> be something like below?
>
> 		if (!pci_is_bridge(dev_res->dev) ||
> 		    index < PCI_BRIDGE_RESOURCES ||
> 		    index > PCI_BRIDGE_RESOURCE_END)
> 			continue;

Yes. I made a mistake here. It should be something like
the above code.

Thanks,
Yongji

> > 		add_align = get_res_add_align(realloc_head, dev_res->res);
> Thanks,
> Gavin
>
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