Re: [PATCH 1/4] x86/ioapic: Support hot-removal of IOAPICs present during boot

[Bjorn Helgaas <helgaas@kernel.org>]

On Tue, Jul 26, 2016 at 03:19:32PM -0500, Bjorn Helgaas wrote:
> On Wed, Jul 27, 2016 at 12:13:14AM +0800, Rui Wang wrote:
> > IOAPICs present during system boot aren't added to ioapic_list,
> > thus are unable to be hot-removed. Fix it by calling
> > acpi_ioapic_add() during root bus enumeration.
> > 
> > Signed-off-by: Rui Wang <rui.y.wang@intel.com>

I should have added:

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

The comments below are minor, and I'm happy if Rafael merges this
series via his tree.

> > ---
> >  drivers/acpi/internal.h |  2 --
> >  drivers/acpi/ioapic.c   |  7 ++++---
> >  drivers/acpi/pci_root.c | 13 ++++++++++++-
> >  drivers/pci/setup-bus.c |  5 ++++-
> >  include/linux/acpi.h    |  6 ++++++
> >  5 files changed, 26 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
> > index 27cc7fe..6d8e67e 100644
> > --- a/drivers/acpi/internal.h
> > +++ b/drivers/acpi/internal.h
> > @@ -40,10 +40,8 @@ int acpi_sysfs_init(void);
> >  void acpi_container_init(void);
> >  void acpi_memory_hotplug_init(void);
> >  #ifdef	CONFIG_ACPI_HOTPLUG_IOAPIC
> > -int acpi_ioapic_add(struct acpi_pci_root *root);
> >  int acpi_ioapic_remove(struct acpi_pci_root *root);
> >  #else
> > -static inline int acpi_ioapic_add(struct acpi_pci_root *root) { return 0; }
> 
> It would be nicer if the interface change and header file munging
> were in a separate patch so they wouldn't obscure the meat of the
> change, i.e., the addition of calls to acpi_ioapic_add().
> 
> >  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 ccdc8db..0f272e2 100644
> > --- a/drivers/acpi/ioapic.c
> > +++ b/drivers/acpi/ioapic.c
> > @@ -189,16 +189,17 @@ exit:
> >  	return AE_OK;
> >  }
> >  
> > -int acpi_ioapic_add(struct acpi_pci_root *root)
> > +int acpi_ioapic_add(acpi_handle root_handle)
> >  {
> >  	acpi_status status, retval = AE_OK;
> >  
> > -	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, root->device->handle,
> > +	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, root_handle,
> >  				     UINT_MAX, handle_ioapic_add, NULL,
> > -				     root->device->handle, (void **)&retval);
> > +				     root_handle, (void **)&retval);
> >  
> >  	return ACPI_SUCCESS(status) && ACPI_SUCCESS(retval) ? 0 : -ENODEV;
> >  }
> > +EXPORT_SYMBOL_GPL(acpi_ioapic_add);
> 
> What loadable module needs to call this?  It shouldn't be exported
> unless there is such a module.
> 
> >  int acpi_ioapic_remove(struct acpi_pci_root *root)
> >  {
> > diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> > index ae3fe4e..d818c61 100644
> > --- a/drivers/acpi/pci_root.c
> > +++ b/drivers/acpi/pci_root.c
> > @@ -614,7 +614,18 @@ static int acpi_pci_root_add(struct acpi_device *device,
> >  	if (hotadd) {
> >  		pcibios_resource_survey_bus(root->bus);
> >  		pci_assign_unassigned_root_bus_resources(root->bus);
> > -		acpi_ioapic_add(root);
> > +
> > +		/*
> > +		 * This is only called for the hotadd case. For the boot-time
> > +		 * case, we need to wait until after PCI initialization in
> > +		 * order to deal with IOAPICs mapped in on a PCI BAR.
> > +		 *
> > +		 * This is currently x86-specific, because acpi_ioapic_add()
> > +		 * is an empty function without CONFIG_ACPI_HOTPLUG_IOAPIC.
> > +		 * And CONFIG_ACPI_HOTPLUG_IOAPIC depends on CONFIG_X86_IO_APIC
> > +		 * (see drivers/acpi/Kconfig).
> > +		 */
> > +		acpi_ioapic_add(root->device->handle);
> >  	}
> >  
> >  	pci_lock_rescan_remove();
> > diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> > index 55641a3..e32c356 100644
> > --- a/drivers/pci/setup-bus.c
> > +++ b/drivers/pci/setup-bus.c
> > @@ -25,6 +25,7 @@
> >  #include <linux/ioport.h>
> >  #include <linux/cache.h>
> >  #include <linux/slab.h>
> > +#include <linux/acpi.h>
> >  #include "pci.h"
> >  
> >  unsigned int pci_flags;
> > @@ -1779,8 +1780,10 @@ void __init pci_assign_unassigned_resources(void)
> >  {
> >  	struct pci_bus *root_bus;
> >  
> > -	list_for_each_entry(root_bus, &pci_root_buses, node)
> > +	list_for_each_entry(root_bus, &pci_root_buses, node) {
> >  		pci_assign_unassigned_root_bus_resources(root_bus);
> > +		acpi_ioapic_add(ACPI_HANDLE(root_bus->bridge));
> > +	}
> >  }
> >  
> >  void pci_assign_unassigned_bridge_resources(struct pci_dev *bridge)
> > diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> > index 288fac5..f5114dc 100644
> > --- a/include/linux/acpi.h
> > +++ b/include/linux/acpi.h
> > @@ -680,6 +680,12 @@ static inline enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)
> >  
> >  #endif	/* !CONFIG_ACPI */
> >  
> > +#ifdef CONFIG_ACPI_HOTPLUG_IOAPIC
> > +int acpi_ioapic_add(acpi_handle root);
> > +#else
> > +static inline int acpi_ioapic_add(acpi_handle root) { return 0; }
> > +#endif
> > +
> >  #ifdef CONFIG_ACPI
> >  void acpi_os_set_prepare_sleep(int (*func)(u8 sleep_state,
> >  			       u32 pm1a_ctrl,  u32 pm1b_ctrl));
> > -- 
> > 1.8.3.1
> > 
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