On 2014/11/19 19:49, Lorenzo Pieralisi wrote: > On Wed, Nov 19, 2014 at 07:32:49AM +0000, Yijing Wang wrote: >> Just like pci_scan_bus(), we also should rip out >> pci_bus_add_devices() from pci_scan_root_bus(). >> Lots platforms first call pci_scan_root_bus(), but >> after that, they call pci_bus_size_bridges() and >> pci_bus_assign_resources(). Place pci_bus_add_devices() >> in pci_scan_root_bus() hurts PCI scan logic. >> Should no functional change. > > I agree with the patch, I do not agree it provides no functional change. > You are actually fixing an issue on systems where the root bus > is scanned at device_initcall time and pci drivers may have already been > registered, so they end up being probed with possibly unassigned > resources as you correctly mention in the log. > > You could move the sequence: > > if (!pci_has_flag(PCI_PROBE_ONLY)) { > pci_bus_size_bridges(); > pci_bus_assign_resources(); > } > > in pci_scan_root_bus() instead of taking pci_bus_add_devices() out ? No, many drivers need additional setup before resources setup. > > Would this break any code ? Or add a helper function: > > pci_scan_root_bus(..., bool assign) ? I don't think it's worth, this make scan function involved something not scan business. > > arm64 xgene code has already been fixed by reshuffling the scanning code > sequence. > > I think we should have a look at eg drivers/pci/host/pcie-xilinx.c, I > think there is a possible initcall ordering issue there (drivers being probed > with unassigned resources). If pci device drivers(like network driver) are loaded before pcie host driver, use pci_scan_root_bus() may cause problem, because pci_bus_add_devices() will try to attach the device driver, but this time pci devices resources may not be configured properly. > > Lorenzo > >> >> Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx> >> CC: linux-alpha@xxxxxxxxxxxxxxx >> CC: linux-ia64@xxxxxxxxxxxxxxx >> CC: linux-mips@xxxxxxxxxxxxxx >> CC: linux-xtensa@xxxxxxxxxxxxxxxx >> CC: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >> CC: linux-sh@xxxxxxxxxxxxxxx >> CC: sparclinux@xxxxxxxxxxxxxxx >> --- >> arch/alpha/kernel/pci.c | 2 ++ >> arch/frv/mb93090-mb00/pci-vdk.c | 6 ++++-- >> arch/ia64/sn/kernel/io_init.c | 1 + >> arch/microblaze/pci/pci-common.c | 1 + >> arch/mips/pci/pci.c | 1 + >> arch/mn10300/unit-asb2305/pci.c | 5 ++++- >> arch/s390/pci/pci.c | 2 +- >> arch/sh/drivers/pci/pci.c | 1 + >> arch/sparc/kernel/leon_pci.c | 1 + >> arch/tile/kernel/pci.c | 2 ++ >> arch/tile/kernel/pci_gx.c | 2 ++ >> arch/x86/pci/common.c | 1 + >> arch/xtensa/kernel/pci.c | 2 ++ >> drivers/pci/host/pci-xgene.c | 1 + >> drivers/pci/probe.c | 1 - >> 15 files changed, 24 insertions(+), 5 deletions(-) >> >> diff --git a/arch/alpha/kernel/pci.c b/arch/alpha/kernel/pci.c >> index 076c35c..97f9730 100644 >> --- a/arch/alpha/kernel/pci.c >> +++ b/arch/alpha/kernel/pci.c >> @@ -334,6 +334,8 @@ common_init_pci(void) >> >> bus = pci_scan_root_bus(NULL, next_busno, alpha_mv.pci_ops, >> hose, &resources); >> + if (bus) >> + pci_bus_add_devices(bus); >> hose->bus = bus; >> hose->need_domain_info = need_domain_info; >> next_busno = bus->busn_res.end + 1; >> diff --git a/arch/frv/mb93090-mb00/pci-vdk.c b/arch/frv/mb93090-mb00/pci-vdk.c >> index efa5d65..2b36044 100644 >> --- a/arch/frv/mb93090-mb00/pci-vdk.c >> +++ b/arch/frv/mb93090-mb00/pci-vdk.c >> @@ -316,6 +316,7 @@ void pcibios_fixup_bus(struct pci_bus *bus) >> >> int __init pcibios_init(void) >> { >> + struct pci_bus *bus; >> struct pci_ops *dir = NULL; >> LIST_HEAD(resources); >> >> @@ -383,12 +384,13 @@ int __init pcibios_init(void) >> printk("PCI: Probing PCI hardware\n"); >> pci_add_resource(&resources, &pci_ioport_resource); >> pci_add_resource(&resources, &pci_iomem_resource); >> - pci_scan_root_bus(NULL, 0, pci_root_ops, NULL, &resources); >> + bus = pci_scan_root_bus(NULL, 0, pci_root_ops, NULL, &resources); >> >> pcibios_irq_init(); >> pcibios_fixup_irqs(); >> pcibios_resource_survey(); >> - >> + if (bus) >> + pci_bus_add_devices(bus); >> return 0; >> } >> >> diff --git a/arch/ia64/sn/kernel/io_init.c b/arch/ia64/sn/kernel/io_init.c >> index 0b5ce82..63b43a6 100644 >> --- a/arch/ia64/sn/kernel/io_init.c >> +++ b/arch/ia64/sn/kernel/io_init.c >> @@ -272,6 +272,7 @@ sn_pci_controller_fixup(int segment, int busnum, struct pci_bus *bus) >> kfree(res); >> kfree(controller); >> } >> + pci_bus_add_devices(bus); >> } >> >> /* >> diff --git a/arch/microblaze/pci/pci-common.c b/arch/microblaze/pci/pci-common.c >> index 9037914..651e25d 100644 >> --- a/arch/microblaze/pci/pci-common.c >> +++ b/arch/microblaze/pci/pci-common.c >> @@ -1346,6 +1346,7 @@ static void pcibios_scan_phb(struct pci_controller *hose) >> hose->bus = bus; >> >> hose->last_busno = bus->busn_res.end; >> + pci_bus_add_devices(bus); >> } >> >> static int __init pcibios_init(void) >> diff --git a/arch/mips/pci/pci.c b/arch/mips/pci/pci.c >> index 1bf60b1..f083688 100644 >> --- a/arch/mips/pci/pci.c >> +++ b/arch/mips/pci/pci.c >> @@ -113,6 +113,7 @@ static void pcibios_scanbus(struct pci_controller *hose) >> if (!pci_has_flag(PCI_PROBE_ONLY)) { >> pci_bus_size_bridges(bus); >> pci_bus_assign_resources(bus); >> + pci_bus_add_devices(bus); >> } >> } >> } >> diff --git a/arch/mn10300/unit-asb2305/pci.c b/arch/mn10300/unit-asb2305/pci.c >> index 6b4339f..860aa35 100644 >> --- a/arch/mn10300/unit-asb2305/pci.c >> +++ b/arch/mn10300/unit-asb2305/pci.c >> @@ -345,6 +345,7 @@ void pcibios_fixup_bus(struct pci_bus *bus) >> */ >> static int __init pcibios_init(void) >> { >> + struct pci_bus *bus; >> resource_size_t io_offset, mem_offset; >> LIST_HEAD(resources); >> >> @@ -376,11 +377,13 @@ static int __init pcibios_init(void) >> >> pci_add_resource_offset(&resources, &pci_ioport_resource, io_offset); >> pci_add_resource_offset(&resources, &pci_iomem_resource, mem_offset); >> - pci_scan_root_bus(NULL, 0, &pci_direct_ampci, NULL, &resources); >> + bus = pci_scan_root_bus(NULL, 0, &pci_direct_ampci, NULL, &resources); >> >> pcibios_irq_init(); >> pcibios_fixup_irqs(); >> pcibios_resource_survey(); >> + if (bus) >> + pci_bus_add_devices(bus); >> return 0; >> } >> >> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c >> index 552b990..98247f8 100644 >> --- a/arch/s390/pci/pci.c >> +++ b/arch/s390/pci/pci.c >> @@ -755,7 +755,7 @@ static int zpci_scan_bus(struct zpci_dev *zdev) >> zpci_cleanup_bus_resources(zdev); >> return -EIO; >> } >> - >> + pci_bus_add_devices(zdev->bus); >> zdev->bus->max_bus_speed = zdev->max_bus_speed; >> return 0; >> } >> diff --git a/arch/sh/drivers/pci/pci.c b/arch/sh/drivers/pci/pci.c >> index 1bc09ee..efc1051 100644 >> --- a/arch/sh/drivers/pci/pci.c >> +++ b/arch/sh/drivers/pci/pci.c >> @@ -69,6 +69,7 @@ static void pcibios_scanbus(struct pci_channel *hose) >> >> pci_bus_size_bridges(bus); >> pci_bus_assign_resources(bus); >> + pci_bus_add_devices(bus); >> } else { >> pci_free_resource_list(&resources); >> } >> diff --git a/arch/sparc/kernel/leon_pci.c b/arch/sparc/kernel/leon_pci.c >> index 899b720..2971076 100644 >> --- a/arch/sparc/kernel/leon_pci.c >> +++ b/arch/sparc/kernel/leon_pci.c >> @@ -40,6 +40,7 @@ void leon_pci_init(struct platform_device *ofdev, struct leon_pci_info *info) >> >> /* Assign devices with resources */ >> pci_assign_unassigned_resources(); >> + pci_bus_add_devices(root_bus); >> } else { >> pci_free_resource_list(&resources); >> } >> diff --git a/arch/tile/kernel/pci.c b/arch/tile/kernel/pci.c >> index 1f80a88..007466e 100644 >> --- a/arch/tile/kernel/pci.c >> +++ b/arch/tile/kernel/pci.c >> @@ -308,6 +308,8 @@ int __init pcibios_init(void) >> pci_add_resource(&resources, &iomem_resource); >> bus = pci_scan_root_bus(NULL, 0, controller->ops, >> controller, &resources); >> + if (bus) >> + pci_bus_add_devices(bus); >> controller->root_bus = bus; >> controller->last_busno = bus->busn_res.end; >> } >> diff --git a/arch/tile/kernel/pci_gx.c b/arch/tile/kernel/pci_gx.c >> index e39f9c5..3f8fb2c 100644 >> --- a/arch/tile/kernel/pci_gx.c >> +++ b/arch/tile/kernel/pci_gx.c >> @@ -889,6 +889,8 @@ int __init pcibios_init(void) >> controller->first_busno = next_busno; >> bus = pci_scan_root_bus(NULL, next_busno, controller->ops, >> controller, &resources); >> + if (bus) >> + pci_bus_add_devices(bus); >> controller->root_bus = bus; >> next_busno = bus->busn_res.end + 1; >> } >> diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c >> index 7b20bcc..300d39e 100644 >> --- a/arch/x86/pci/common.c >> +++ b/arch/x86/pci/common.c >> @@ -475,6 +475,7 @@ void pcibios_scan_root(int busnum) >> pci_free_resource_list(&resources); >> kfree(sd); >> } >> + pci_bus_add_devices(bus); >> } >> >> void __init pcibios_set_cache_line_size(void) >> diff --git a/arch/xtensa/kernel/pci.c b/arch/xtensa/kernel/pci.c >> index 5b34033..f2ae64e 100644 >> --- a/arch/xtensa/kernel/pci.c >> +++ b/arch/xtensa/kernel/pci.c >> @@ -185,6 +185,8 @@ static int __init pcibios_init(void) >> pci_controller_apertures(pci_ctrl, &resources); >> bus = pci_scan_root_bus(NULL, pci_ctrl->first_busno, >> pci_ctrl->ops, pci_ctrl, &resources); >> + if (bus) >> + pci_bus_add_devices(bus); >> pci_ctrl->bus = bus; >> pci_ctrl->last_busno = bus->busn_res.end; >> if (next_busno <= pci_ctrl->last_busno) >> diff --git a/drivers/pci/host/pci-xgene.c b/drivers/pci/host/pci-xgene.c >> index 9ecabfa..c17afe5 100644 >> --- a/drivers/pci/host/pci-xgene.c >> +++ b/drivers/pci/host/pci-xgene.c >> @@ -635,6 +635,7 @@ static int xgene_pcie_probe_bridge(struct platform_device *pdev) >> if (!bus) >> return -ENOMEM; >> >> + pci_bus_add_devices(bus); >> platform_set_drvdata(pdev, port); >> return 0; >> } >> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c >> index 79775b5..2ab5a40 100644 >> --- a/drivers/pci/probe.c >> +++ b/drivers/pci/probe.c >> @@ -2084,7 +2084,6 @@ struct pci_bus *pci_scan_root_bus(struct device *parent, int bus, >> if (!found) >> pci_bus_update_busn_res_end(b, max); >> >> - pci_bus_add_devices(b); >> return b; >> } >> EXPORT_SYMBOL(pci_scan_root_bus); >> -- >> 1.7.1 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-pci" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > . > -- Thanks! Yijing -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html