Re: [Patch Part3 V1 17/22] pci, ACPI, iommu: enhance pci_root to support DMAR device hotplug

From: Rafael J. Wysocki
Date: Tue Apr 22 2014 - 05:33:40 EST


On Tuesday, April 22, 2014 03:07:28 PM Jiang Liu wrote:
> Finally enhance pci_root driver to support DMAR device hotplug when
> hot-plugging PCI host bridges.
>
> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
> ---
> drivers/acpi/pci_root.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index d388f13d48b4..aa8f549869f3 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -33,6 +33,7 @@
> #include <linux/pci.h>
> #include <linux/pci-acpi.h>
> #include <linux/pci-aspm.h>
> +#include <linux/dmar.h>
> #include <linux/acpi.h>
> #include <linux/slab.h>
> #include <acpi/apei.h> /* for acpi_hest_init() */
> @@ -511,6 +512,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
> struct acpi_pci_root *root;
> acpi_handle handle = device->handle;
> int no_aspm = 0, clear_aspm = 0;
> + bool hotadd = (system_state != SYSTEM_BOOTING);

The parens are not necessary in the above instruction.

> root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
> if (!root)
> @@ -557,6 +559,11 @@ static int acpi_pci_root_add(struct acpi_device *device,
> strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
> device->driver_data = root;
>
> + if (hotadd && dmar_device_hotplug(handle, true)) {
> + result = -ENXIO;
> + goto end;
> + }
> +
> pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
> acpi_device_name(device), acpi_device_bid(device),
> root->segment, &root->secondary);
> @@ -583,7 +590,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
> root->segment, (unsigned int)root->secondary.start);
> device->driver_data = NULL;
> result = -ENODEV;
> - goto end;
> + goto remove_dmar;
> }
>
> if (clear_aspm) {
> @@ -597,7 +604,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
> if (device->wakeup.flags.run_wake)
> device_set_run_wake(root->bus->bridge, true);
>
> - if (system_state != SYSTEM_BOOTING) {
> + if (hotadd) {
> pcibios_resource_survey_bus(root->bus);
> pci_assign_unassigned_root_bus_resources(root->bus);
> }
> @@ -607,6 +614,9 @@ static int acpi_pci_root_add(struct acpi_device *device,
> pci_unlock_rescan_remove();
> return 1;
>
> +remove_dmar:
> + if (hotadd)
> + dmar_device_hotplug(handle, false);

I suppose that works if dmar_device_hotplug() returned false before?

> end:
> kfree(root);
> return result;
> @@ -625,6 +635,8 @@ static void acpi_pci_root_remove(struct acpi_device *device)
>
> pci_remove_root_bus(root->bus);
>
> + dmar_device_hotplug(device->handle, false);
> +
> pci_unlock_rescan_remove();
>
> kfree(root);
>

--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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