[PATCH v2 2/2] x86/ioapic: Split IOAPIC hot-removal into two steps

From: Rui Wang
Date: Tue Feb 28 2017 - 08:52:19 EST


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.

v2: Fixed compiling error on i386 (missing stub of pci_ioapic_remove())

Signed-off-by: Rui Wang <rui.y.wang@xxxxxxxxx>
---
drivers/acpi/internal.h | 2 ++
drivers/acpi/ioapic.c | 22 ++++++++++++++++------
drivers/acpi/pci_root.c | 4 ++--
3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 219b90b..f159001 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -41,8 +41,10 @@ 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 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 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