The hot-removal of IOAPIC is 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 that the IOAPIC driver is able to hook the
pcibios_release_device() of every PCI device under the same parent root
bus, before the IOAPIC is hot-removed. This makes it possible for the
IOAPIC to free any IRQ resource previously unable to get freed.

Signed-off-by: Rui Wang <rui.y.w...@intel.com>
---
 drivers/acpi/internal.h |  1 +
 drivers/acpi/ioapic.c   | 22 ++++++++++++++++------
 drivers/acpi/pci_root.c |  4 ++--
 3 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 219b90b..b2e3416 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -41,6 +41,7 @@ static inline void acpi_amba_init(void) {}
 void acpi_container_init(void);
 void acpi_memory_hotplug_init(void);
 #ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
+void pci_ioapic_remove(struct acpi_pci_root *root);
 int acpi_ioapic_remove(struct acpi_pci_root *root);
 #else
 static inline int acpi_ioapic_remove(struct acpi_pci_root *root) { return 0; }
diff --git a/drivers/acpi/ioapic.c b/drivers/acpi/ioapic.c
index 6d7ce6e..1120dfd6 100644
--- a/drivers/acpi/ioapic.c
+++ b/drivers/acpi/ioapic.c
@@ -206,24 +206,34 @@ int acpi_ioapic_add(acpi_handle root_handle)
        return ACPI_SUCCESS(status) && ACPI_SUCCESS(retval) ? 0 : -ENODEV;
 }
 
-int acpi_ioapic_remove(struct acpi_pci_root *root)
+void pci_ioapic_remove(struct acpi_pci_root *root)
 {
-       int retval = 0;
        struct acpi_pci_ioapic *ioapic, *tmp;
 
        mutex_lock(&ioapic_list_lock);
        list_for_each_entry_safe(ioapic, tmp, &ioapic_list, list) {
                if (root->device->handle != ioapic->root_handle)
                        continue;
-
-               if (acpi_unregister_ioapic(ioapic->handle, ioapic->gsi_base))
-                       retval = -EBUSY;
-
                if (ioapic->pdev) {
                        pci_release_region(ioapic->pdev, 0);
                        pci_disable_device(ioapic->pdev);
                        pci_dev_put(ioapic->pdev);
                }
+       }
+       mutex_unlock(&ioapic_list_lock);
+}
+
+int acpi_ioapic_remove(struct acpi_pci_root *root)
+{
+       int retval = 0;
+       struct acpi_pci_ioapic *ioapic, *tmp;
+
+       mutex_lock(&ioapic_list_lock);
+       list_for_each_entry_safe(ioapic, tmp, &ioapic_list, list) {
+               if (root->device->handle != ioapic->root_handle)
+                       continue;
+               if (acpi_unregister_ioapic(ioapic->handle, ioapic->gsi_base))
+                       retval = -EBUSY;
                if (ioapic->res.flags && ioapic->res.parent)
                        release_resource(&ioapic->res);
                list_del(&ioapic->list);
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index bf601d4..919be0a 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -648,12 +648,12 @@ static void acpi_pci_root_remove(struct acpi_device 
*device)
 
        pci_stop_root_bus(root->bus);
 
-       WARN_ON(acpi_ioapic_remove(root));
-
+       pci_ioapic_remove(root);
        device_set_run_wake(root->bus->bridge, false);
        pci_acpi_remove_bus_pm_notifier(device);
 
        pci_remove_root_bus(root->bus);
+       WARN_ON(acpi_ioapic_remove(root));
 
        dmar_device_remove(device->handle);
 
-- 
1.8.3.1

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