x86/ioapic: Split IOAPIC hot-removal into two steps

The hot removal of IOAPIC is handling PCI and ACPI removal in one go. That
only works when the PCI drivers released the interrupt resources, but
breaks when a IOAPIC interrupt is still associated to a PCI device.

The new pcibios_release_device() callback allows to solve that problem by
splitting the removal into two steps:

1) PCI removal:

   Release all PCI resources including eventually not yet released IOAPIC
   interrupts via the new pcibios_release_device() callback.

2) ACPI removal:

   After release of all PCI resources the ACPI resources can be released
   without issue.

[ tglx: Rewrote changelog ]

Signed-off-by: Rui Wang <rui.y.wang@intel.com>
Cc: tony.luck@intel.com
Cc: linux-pci@vger.kernel.org
Cc: rjw@rjwysocki.net
Cc: linux-acpi@vger.kernel.org
Cc: fengguang.wu@intel.com
Cc: helgaas@kernel.org
Cc: kbuild-all@01.org
Cc: bhelgaas@google.com
Link: http://lkml.kernel.org/r/1488288869-31290-3-git-send-email-rui.y.wang@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 20 insertions, 8 deletions

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 219b90bc0922..f15900132912 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -41,8 +41,10 @@ void acpi_gpe_apply_masked_gpes(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 void pci_ioapic_remove(struct acpi_pci_root *root) { return; }
 static inline int acpi_ioapic_remove(struct acpi_pci_root *root) { return 0; }
 #endif
 #ifdef CONFIG_ACPI_DOCK
diff --git a/drivers/acpi/ioapic.c b/drivers/acpi/ioapic.c
index 6d7ce6e12aaa..1120dfd625b8 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 bf601d4df8cf..919be0aa2578 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);