Have callers invoke pci_add_segment() directly instead: With radix tree initialization moved out of the function, its name isn't quite describing anymore what it actually does.
On x86 move the logic into __start_xen() itself, to reduce the risk of re-introducing ordering issues like the one which was addressed by 26fe09e34566 ("radix-tree: introduce RADIX_TREE{,_INIT}()"). Signed-off-by: Jan Beulich <jbeul...@suse.com> --- This is entirely optional and up for discussion. There certainly also is an argument towards keeping the function. Otoh on Arm there is the still open question whether segment 0 really is kind of special there (as it is on x86, largely for historical reasons), or whether the code can be dropped there altogether. --- v4: Move x86 logic into __start_xen() itself. v3: Adjust description to account for and re-base over dropped earlier patch. v2: New. --- a/xen/arch/arm/pci/pci.c +++ b/xen/arch/arm/pci/pci.c @@ -88,7 +88,8 @@ static int __init pci_init(void) if ( !pci_passthrough_enabled ) return 0; - pci_segments_init(); + if ( pci_add_segment(0) ) + panic("Could not initialize PCI segment 0\n"); if ( acpi_disabled ) return dt_pci_init(); --- a/xen/arch/x86/x86_64/mmconfig-shared.c +++ b/xen/arch/x86/x86_64/mmconfig-shared.c @@ -402,8 +402,6 @@ void __init acpi_mmcfg_init(void) { bool valid = true; - pci_segments_init(); - /* MMCONFIG disabled */ if ((pci_probe & PCI_PROBE_MMCONF) == 0) return; --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -1898,6 +1898,13 @@ void asmlinkage __init noreturn __start_ setup_system_domains(); /* + * Ahead of any ACPI table parsing make sure we have control structures + * for PCI segment 0. + */ + if ( pci_add_segment(0) ) + panic("Could not initialize PCI segment 0\n"); + + /* * IOMMU-related ACPI table parsing has to happen before APIC probing, for * check_x2apic_preenabled() to be able to observe respective findings, in * particular iommu_intremap having got turned off. --- a/xen/drivers/passthrough/pci.c +++ b/xen/drivers/passthrough/pci.c @@ -127,12 +127,6 @@ static int pci_segments_iterate( return rc; } -void __init pci_segments_init(void) -{ - if ( !alloc_pseg(0) ) - panic("Could not initialize PCI segment 0\n"); -} - int __init pci_add_segment(u16 seg) { return alloc_pseg(seg) ? 0 : -ENOMEM; --- a/xen/include/xen/pci.h +++ b/xen/include/xen/pci.h @@ -219,7 +219,6 @@ void setup_hwdom_pci_devices(struct doma int (*handler)(uint8_t devfn, struct pci_dev *pdev)); int pci_release_devices(struct domain *d); -void pci_segments_init(void); int pci_add_segment(u16 seg); const unsigned long *pci_get_ro_map(u16 seg); int pci_add_device(u16 seg, u8 bus, u8 devfn,