Hi Bjorn,
On 2017/5/25 6:30, Bjorn Helgaas wrote:
Hi Shawn,
On Tue, May 23, 2017 at 03:45:11PM +0800, Shawn Lin wrote:
[...]
+ domain = pci_get_new_domain_nr(bus);
These comments and logic are too complicated for my puny brain. Much of
this was pre-existing, of course. Surely there's a simpler way?
yup, I think we could simplify the code.
1) If we're using ACPI, every host bridge must have a _SEG method, and it
supplies the domain. We ignore any bridge without _SEG.
2) If we're using DT, every host bridge must supply "linux,pci-domain", and
it supplies the domain. We ignore any bridge without "linux,pci-domain".
3) Otherwise, we always use IDA.
I plan to create a new function to allocate domain number using IDA as
then we don't touch the logic of of_pci_bus_find_domain_nr, and the
name of of_pci_bus_find_domain_nr explicitly say that the domain number
comes from DT.
Then I could put the condition check inside the pci_bus_find_domain_nr
as your suggested.
Does it looks ok to you?
} else {
dev_err(parent, "Node %s has inconsistent \"linux,pci-domain\" property in DT\n",
[...]
pci_remove_bus_device(child);
+
+ pci_put_old_domain_nr(bus);
In your current patch, ida_domain defaults to true, and it is only set
to false in of_pci_bus_find_domain_nr(), which is only called when
ACPI is disabled. Therefore, ida_domain will be true when we're using
ACPI, and I think pci_put_old_domain_nr() will erroneously remove
domains from tha IDA.
woops, I forgot to check the ACPI cases.
pci_remove_bus(bus);
host_bridge->bus = NULL;
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 33c2b0b..9296e31 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1445,13 +1445,17 @@ static inline int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
* configuration space.
*/
#ifdef CONFIG_PCI_DOMAINS
+extern struct ida __domain_nr;
extern int pci_domains_supported;
-int pci_get_new_domain_nr(void);
+int pci_get_new_domain_nr(struct pci_bus *bus);
+void pci_put_old_domain_nr(struct pci_bus *bus);
#else
enum { pci_domains_supported = 0 };
static inline int pci_domain_nr(struct pci_bus *bus) { return 0; }
static inline int pci_proc_domain(struct pci_bus *bus) { return 0; }
-static inline int pci_get_new_domain_nr(void) { return -ENOSYS; }
+static inline int pci_get_new_domain_nr(struct pci_bus *bus)
+{ return -ENOSYS; }
+static inline void pci_put_old_domain_nr(struct pci_bus *bus) { }
#endif /* CONFIG_PCI_DOMAINS */
/*
--
1.9.1
