On Wed, Feb 8, 2012 at 8:08 AM, Bjorn Helgaas [off-list ref] wrote:

On Sat, Feb 4, 2012 at 10:57 PM, Yinghai Lu [off-list ref] wrote:

quoted

update pci_scan_root_bus, and pci_scan_bus to insert root bus busn into
iobusn_resource tree.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 drivers/pci/probe.c  |   30 ++++++++++++++++++++++++++----
 drivers/pci/remove.c |    1 +
 include/linux/pci.h  |    4 ++++
 3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index fabf9d0..cdd6e83 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c

@@ -1667,8 +1667,9 @@ void pci_bus_release_busn_res(struct pci_bus *b)

                       res, ret ? "can not be" : "is");
 }

-struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,
-               struct pci_ops *ops, void *sysdata, struct list_head *resources)
+struct pci_bus * __devinit pci_scan_root_bus_max(struct device *parent, int bus,
+               int bus_max, struct pci_ops *ops, void *sysdata,
+               struct list_head *resources)
 {
       struct pci_bus *b;

@@ -1676,10 +1677,26 @@ struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,

       if (!b)
               return NULL;

+       pci_bus_insert_busn_res(b, bus, bus_max);
       b->subordinate = pci_scan_child_bus(b);
       pci_bus_add_devices(b);
       return b;
 }
+EXPORT_SYMBOL(pci_scan_root_bus_max);
+
+struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,
+               struct pci_ops *ops, void *sysdata,
+               struct list_head *resources)
+{
+       struct pci_bus *b;
+
+       b = pci_scan_root_bus_max(parent, bus, 255, ops, sysdata, resources);
+
+       if (b)
+               pci_bus_update_busn_res_end(b, b->subordinate);
+
+       return b;
+}
 EXPORT_SYMBOL(pci_scan_root_bus);

 /* Deprecated; use pci_scan_root_bus() instead */

@@ -1692,9 +1709,11 @@ struct pci_bus * __devinit pci_scan_bus_parented(struct device *parent,

       pci_add_resource(&resources, &ioport_resource);
       pci_add_resource(&resources, &iomem_resource);
       b = pci_create_root_bus(parent, bus, ops, sysdata, &resources);
-       if (b)
+       if (b) {
+               pci_bus_insert_busn_res(b, bus, 255);
               b->subordinate = pci_scan_child_bus(b);
-       else
+               pci_bus_update_busn_res_end(b, b->subordinate);
+       } else
               pci_free_resource_list(&resources);
       return b;
 }

@@ -1710,7 +1729,10 @@ struct pci_bus * __devinit pci_scan_bus(int bus, struct pci_ops *ops,

       pci_add_resource(&resources, &iomem_resource);
       b = pci_create_root_bus(NULL, bus, ops, sysdata, &resources);
       if (b) {
+               pci_bus_insert_busn_res(b, bus, 255);
               b->subordinate = pci_scan_child_bus(b);
+               pci_bus_update_busn_res_end(b, b->subordinate);
+
               pci_bus_add_devices(b);
       } else {
               pci_free_resource_list(&resources);

diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index 82f8ae5..5b679d2 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c

@@ -68,6 +68,7 @@ void pci_remove_bus(struct pci_bus *pci_bus)

       down_write(&pci_bus_sem);
       list_del(&pci_bus->node);
+       pci_bus_release_busn_res(pci_bus);
       up_write(&pci_bus_sem);
       if (!pci_bus->is_added)
               return;

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 3da935c..d5b6786 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h

@@ -668,6 +668,10 @@ struct pci_bus *pci_create_root_bus(struct device *parent, int bus,

 void pci_bus_insert_busn_res(struct pci_bus *b, int bus, int busmax);
 void pci_bus_update_busn_res_end(struct pci_bus *b, int busmax);
 void pci_bus_release_busn_res(struct pci_bus *b);
+struct pci_bus * __devinit pci_scan_root_bus_max(struct device *parent, int bus,
+                                            int busmax, struct pci_ops *ops,
+                                            void *sysdata,
+                                            struct list_head *resources);
 struct pci_bus * __devinit pci_scan_root_bus(struct device *parent, int bus,
                                            struct pci_ops *ops, void *sysdata,
                                            struct list_head *resources);

Now we have both pci_bus_insert_busn_res() and
pci_scan_root_bus_max().  Why do we need both?  I think it's too much
of a burden on architectures to expect them to understand both.

Maybe some sample pseudo-code using both interfaces would help me
understand what you expect a typical architecture to do.

We need to call pci_bus_insert_busn_res for root bus:
1. after that bus is allocated (...) : that busn_res is in the bus struct.
2. before pci_scan_child_bus

Yinghai