| Message ID | 1488204944-27189-2-git-send-email-rui.y.wang@intel.com |
|---|---|
| State | Superseded |
| Headers | show |
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c index 0cb52ae..4eba071 100644 --- a/arch/x86/pci/common.c +++ b/arch/x86/pci/common.c @@ -735,6 +735,15 @@ void pcibios_disable_device (struct pci_dev *dev) pcibios_disable_irq(dev); } +#ifdef CONFIG_ACPI_HOTPLUG_IOAPIC +void pcibios_release_device(struct pci_dev *dev) +{ + if (atomic_dec_return(&dev->enable_cnt) >=0) + pcibios_disable_device(dev); + +} +#endif + int pci_ext_cfg_avail(void) { if (raw_pci_ext_ops)
The revert of 991de2e59090 ("PCI, x86: Implement pcibios_alloc_irq() and pcibios_free_irq()") causes a problem for IOAPIC hotplug. The problem is that IRQs are allocated and freed in pci_enable_device() and pci_disable_device(). But there are some drivers which don't call pci_disable_device(), and they have good reasons not calling it, so if they're using IOAPIC their IRQs won't have a chance to be released from the IOAPIC. When this happens IOAPIC hot-removal fails with a kernel stack dump and an error message like this: [149335.697989] pin16 on IOAPIC2 is still in use. It turns out that we can fix it in a different way without moving IRQ allocation into pcibios_alloc_irq(), thus avoiding the regression of 991de2e59090. We can keep the allocation and freeing of IRQs as is within pci_enable_device()/pci_disable_device(), without breaking any previous assumption of the rest of the system, keeping compatibility with both the legacy and the modern drivers. We can accomplish this by implementing the existing __weak hook of pcibios_release_device() thus when a pci device is about to be deleted we get notified in the hook and take the chance to release its IRQ, if any, from the IOAPIC. Besides implementing pcibios_release_device(), the hot-removal of IOAPIC needs to be broken into two parts: the PCI part and the ACPI part. The PCI part releases PCI resources before the PCI bus is gone, and the ACPI part is moved to a stage later than the hot-removal of the PCI root bus, so we have the chance to hook every PCI device's pcibios_release_device(), before we remove the IOAPIC. This patch implements pcibios_release_device() on x86 to release any IRQ not released by the driver, so that the IOAPIC can then be safely hot-removed. Signed-off-by: Rui Wang <rui.y.wang@intel.com> --- arch/x86/pci/common.c | 9 +++++++++ 1 file changed, 9 insertions(+)