Messages in this thread Patch in this message | | | From | Nicholas Johnson <> | Subject | [PATCH v9 4/4] PCI: Allow extend_bridge_window() to shrink resource if necessary | Date | Tue, 29 Oct 2019 15:29:21 +0000 |
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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@outlook.com.au> --- 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); + } - add_size = new_size - resource_size(res); - pci_dbg(bridge, "bridge window %pR extended by %pa\n", res, &add_size); res->end = res->start + new_size - 1; remove_from_list(add_list, res); + if (!new_size) + reset_resource(res); } static void pci_bus_distribute_available_resources(struct pci_bus *bus, @@ -1865,9 +1872,9 @@ static void pci_bus_distribute_available_resources(struct pci_bus *bus, * Update the resources to fill as much remaining resource space in the * parent bridge as possible, while considering alignment. */ - extend_bridge_window(bridge, io_res, add_list, resource_size(&io)); - extend_bridge_window(bridge, mmio_res, add_list, resource_size(&mmio)); - extend_bridge_window(bridge, mmio_pref_res, add_list, + adjust_bridge_window(bridge, io_res, add_list, resource_size(&io)); + adjust_bridge_window(bridge, mmio_res, add_list, resource_size(&mmio)); + adjust_bridge_window(bridge, mmio_pref_res, add_list, resource_size(&mmio_pref)); /* -- 2.23.0
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