On Wed, Oct 30, 2019 at 01:22:44PM +0000, Nicholas Johnson wrote:
> On Wed, Oct 30, 2019 at 02:07:05PM +0200, mika.westerberg@xxxxxxxxxxxxxxx wrote:
> > On Tue, Oct 29, 2019 at 03:29:21PM +0000, Nicholas Johnson wrote:
> > > Remove checks for resource size in extend_bridge_window(). This is
> > > necessary to allow the pci_bus_distribute_available_resources() to
> > > function when the kernel parameter pci=hpmemsize=nn[KMG] is used to
> > > allocate resources. Because the kernel parameter sets the size of all
> > > hotplug bridges to be the same, there are problems when nested hotplug
> > > bridges are encountered. Fitting a downstream hotplug bridge with size X
> > > and normal bridges with non-zero size Y into parent hotplug bridge with
> > > size X is impossible, and hence the downstream hotplug bridge needs to
> > > shrink to fit into its parent.
> > >
> > > Add check for if bridge is extended or shrunken and adjust pci_dbg to
> > > reflect this.
> > >
> > > Reset the resource if its new size is zero (if we have run out of a
> > > bridge window resource) to prevent the PCI resource assignment code from
> > > attempting to assign a zero-sized resource.
> > >
> > > Rename extend_bridge_window() to adjust_bridge_window() to reflect the
> > > fact that the window can now shrink.
> > >
> > > Signed-off-by: Nicholas Johnson <nicholas.johnson-opensource@xxxxxxxxxxxxxx>
> > > ---
> > > drivers/pci/setup-bus.c | 23 +++++++++++++++--------
> > > 1 file changed, 15 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> > > index fe8b2c715..f8cd54584 100644
> > > --- a/drivers/pci/setup-bus.c
> > > +++ b/drivers/pci/setup-bus.c
> > > @@ -1814,7 +1814,7 @@ void __init pci_assign_unassigned_resources(void)
> > > }
> > > }
> > >
> > > -static void extend_bridge_window(struct pci_dev *bridge, struct resource *res,
> > > +static void adjust_bridge_window(struct pci_dev *bridge, struct resource *res,
> > > struct list_head *add_list,
> > > resource_size_t new_size)
> > > {
> > > @@ -1823,13 +1823,20 @@ static void extend_bridge_window(struct pci_dev *bridge, struct resource *res,
> > > if (res->parent)
> > > return;
> > >
> > > - if (resource_size(res) >= new_size)
> > > - return;
> > > + if (new_size > resource_size(res)) {
> > > + add_size = new_size - resource_size(res);
> > > + pci_dbg(bridge, "bridge window %pR extended by %pa\n", res,
> > > + &add_size);
> > > + } else if (new_size < resource_size(res)) {
> > > + add_size = resource_size(res) - new_size;
> > > + pci_dbg(bridge, "bridge window %pR shrunken by %pa\n", res,
> > > + &add_size);
> > > + }
> >
> > Do we need to care about new_size == resource_size(res)?
> Sorry, I skipped over this before re-posting. If we are not changing the
> size, does it need to be logged in pci_dbg? I could change it to ">=",
> meaning if the size does not change then it will be "extended" by 0 in
> pci_dbg.
>
> Let me know if you wish for this to happen. But I am easy either way.
No need.
> If you are fine with how it is, PATCH v10 should have addressed
> everything so far.
Yes, v10 looks fine by me.
