From: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx> Sent: Wednesday, August 24, 2022 10:00 AM
>
> The parent field in struct acpi_device is, in fact, redundant,
> because the dev.parent field in it effectively points to the same
> object and it is used by the driver core.
>
> Accordingly, the parent field can be dropped from struct acpi_device
> and for this purpose define acpi_dev_parent() to retrieve a parent
> struct acpi_device pointer from the dev.parent field in struct
> acpi_device. Next, update all of the users of the parent field
> in struct acpi_device to use acpi_dev_parent() instead of it and
> drop it.
>
> While at it, drop the ACPI_IS_ROOT_DEVICE() macro that is only used
> in one place in a confusing way.
>
> No intentional functional impact.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> Acked-by: Mark Brown <broonie@xxxxxxxxxx>
> Acked-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> Acked-by: Wei Liu <wei.liu@xxxxxxxxxx>
> Reviewed-by: Punit Agrawal <punit.agrawal@xxxxxxxxxxxxx>
Tested the full patch series in Azure VMs running on Hyper-V --
one x86/x64 and one ARM64. Testing includes standard VMbus
devices as well as virtual PCI devices (Mellanox CX-5 Virtual
Function). Verified that ACPI device cache coherence property is
propagated through the hierarchy of devices that the VMbus and
Hyper-V virtual PCI drivers set up.
Tested-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> ---
>
> v1 -> v2:
> * Cover 3 more users of the parent field in struct acpi_device.
> * Add tags collected so far.
>
> ---
> drivers/acpi/acpi_amba.c | 5 +++--
> drivers/acpi/acpi_platform.c | 6 +++---
> drivers/acpi/acpi_video.c | 2 +-
> drivers/acpi/device_pm.c | 19 ++++++++++---------
> drivers/acpi/property.c | 6 ++++--
> drivers/acpi/sbs.c | 2 +-
> drivers/acpi/sbshc.c | 2 +-
> drivers/acpi/scan.c | 17 ++++++-----------
> drivers/hv/vmbus_drv.c | 3 ++-
> drivers/perf/arm_dsu_pmu.c | 4 ++--
> drivers/perf/qcom_l3_pmu.c | 3 ++-
> drivers/spi/spi.c | 2 +-
> drivers/thunderbolt/acpi.c | 2 +-
> include/acpi/acpi_bus.h | 10 +++++++++-
> 14 files changed, 46 insertions(+), 37 deletions(-)
>
> Index: linux-pm/drivers/acpi/scan.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/scan.c
> +++ linux-pm/drivers/acpi/scan.c
> @@ -29,8 +29,6 @@ extern struct acpi_device *acpi_root;
> #define ACPI_BUS_HID "LNXSYBUS"
> #define ACPI_BUS_DEVICE_NAME "System Bus"
>
> -#define ACPI_IS_ROOT_DEVICE(device) (!(device)->parent)
> -
> #define INVALID_ACPI_HANDLE ((acpi_handle)empty_zero_page)
>
> static const char *dummy_hid = "device";
> @@ -1110,7 +1108,7 @@ static void acpi_device_get_busid(struct
> * The device's Bus ID is simply the object name.
> * TBD: Shouldn't this value be unique (within the ACPI namespace)?
> */
> - if (ACPI_IS_ROOT_DEVICE(device)) {
> + if (!acpi_dev_parent(device)) {
> strcpy(device->pnp.bus_id, "ACPI");
> return;
> }
> @@ -1646,7 +1644,7 @@ static void acpi_init_coherency(struct a
> {
> unsigned long long cca = 0;
> acpi_status status;
> - struct acpi_device *parent = adev->parent;
> + struct acpi_device *parent = acpi_dev_parent(adev);
>
> if (parent && parent->flags.cca_seen) {
> /*
> @@ -1690,7 +1688,7 @@ static int acpi_check_serial_bus_slave(s
>
> static bool acpi_is_indirect_io_slave(struct acpi_device *device)
> {
> - struct acpi_device *parent = device->parent;
> + struct acpi_device *parent = acpi_dev_parent(device);
> static const struct acpi_device_id indirect_io_hosts[] = {
> {"HISI0191", 0},
> {}
> @@ -1767,10 +1765,7 @@ void acpi_init_device_object(struct acpi
> INIT_LIST_HEAD(&device->pnp.ids);
> device->device_type = type;
> device->handle = handle;
> - if (parent) {
> - device->parent = parent;
> - device->dev.parent = &parent->dev;
> - }
> + device->dev.parent = parent ? &parent->dev : NULL;
> device->dev.release = release;
> device->dev.bus = &acpi_bus_type;
> fwnode_init(&device->fwnode, &acpi_device_fwnode_ops);
> @@ -1867,8 +1862,8 @@ static int acpi_add_single_object(struct
> acpi_device_add_finalize(device);
>
> acpi_handle_debug(handle, "Added as %s, parent %s\n",
> - dev_name(&device->dev), device->parent ?
> - dev_name(&device->parent->dev) : "(null)");
> + dev_name(&device->dev), device->dev.parent ?
> + dev_name(device->dev.parent) : "(null)");
>
> *child = device;
> return 0;
> Index: linux-pm/include/acpi/acpi_bus.h
> ===================================================================
> --- linux-pm.orig/include/acpi/acpi_bus.h
> +++ linux-pm/include/acpi/acpi_bus.h
> @@ -365,7 +365,6 @@ struct acpi_device {
> int device_type;
> acpi_handle handle; /* no handle for fixed hardware */
> struct fwnode_handle fwnode;
> - struct acpi_device *parent;
> struct list_head wakeup_list;
> struct list_head del_list;
> struct acpi_device_status status;
> @@ -458,6 +457,14 @@ static inline void *acpi_driver_data(str
> #define to_acpi_device(d) container_of(d, struct acpi_device, dev)
> #define to_acpi_driver(d) container_of(d, struct acpi_driver, drv)
>
> +static inline struct acpi_device *acpi_dev_parent(struct acpi_device *adev)
> +{
> + if (adev->dev.parent)
> + return to_acpi_device(adev->dev.parent);
> +
> + return NULL;
> +}
> +
> static inline void acpi_set_device_status(struct acpi_device *adev, u32 sta)
> {
> *((u32 *)&adev->status) = sta;
> @@ -478,6 +485,7 @@ void acpi_initialize_hp_context(struct a
> /* acpi_device.dev.bus == &acpi_bus_type */
> extern struct bus_type acpi_bus_type;
>
> +struct acpi_device *acpi_dev_parent(struct acpi_device *adev);
> int acpi_bus_for_each_dev(int (*fn)(struct device *, void *), void *data);
> int acpi_dev_for_each_child(struct acpi_device *adev,
> int (*fn)(struct acpi_device *, void *), void *data);
> Index: linux-pm/drivers/acpi/property.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/property.c
> +++ linux-pm/drivers/acpi/property.c
> @@ -304,8 +304,10 @@ static void acpi_init_of_compatible(stru
> ret = acpi_dev_get_property(adev, "compatible",
> ACPI_TYPE_STRING, &of_compatible);
> if (ret) {
> - if (adev->parent
> - && adev->parent->flags.of_compatible_ok)
> + struct acpi_device *parent;
> +
> + parent = acpi_dev_parent(adev);
> + if (parent && parent->flags.of_compatible_ok)
> goto out;
>
> return;
> Index: linux-pm/drivers/acpi/device_pm.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/device_pm.c
> +++ linux-pm/drivers/acpi/device_pm.c
> @@ -74,6 +74,7 @@ static int acpi_dev_pm_explicit_get(stru
> */
> int acpi_device_get_power(struct acpi_device *device, int *state)
> {
> + struct acpi_device *parent = acpi_dev_parent(device);
> int result = ACPI_STATE_UNKNOWN;
> int error;
>
> @@ -82,8 +83,7 @@ int acpi_device_get_power(struct acpi_de
>
> if (!device->flags.power_manageable) {
> /* TBD: Non-recursive algorithm for walking up hierarchy. */
> - *state = device->parent ?
> - device->parent->power.state : ACPI_STATE_D0;
> + *state = parent ? parent->power.state : ACPI_STATE_D0;
> goto out;
> }
>
> @@ -122,10 +122,10 @@ int acpi_device_get_power(struct acpi_de
> * point, the fact that the device is in D0 implies that the parent has
> * to be in D0 too, except if ignore_parent is set.
> */
> - if (!device->power.flags.ignore_parent && device->parent
> - && device->parent->power.state == ACPI_STATE_UNKNOWN
> - && result == ACPI_STATE_D0)
> - device->parent->power.state = ACPI_STATE_D0;
> + if (!device->power.flags.ignore_parent && parent &&
> + parent->power.state == ACPI_STATE_UNKNOWN &&
> + result == ACPI_STATE_D0)
> + parent->power.state = ACPI_STATE_D0;
>
> *state = result;
>
> @@ -159,6 +159,7 @@ static int acpi_dev_pm_explicit_set(stru
> */
> int acpi_device_set_power(struct acpi_device *device, int state)
> {
> + struct acpi_device *parent = acpi_dev_parent(device);
> int target_state = state;
> int result = 0;
>
> @@ -191,12 +192,12 @@ int acpi_device_set_power(struct acpi_de
> return -ENODEV;
> }
>
> - if (!device->power.flags.ignore_parent && device->parent &&
> - state < device->parent->power.state) {
> + if (!device->power.flags.ignore_parent && parent &&
> + state < parent->power.state) {
> acpi_handle_debug(device->handle,
> "Cannot transition to %s for parent in %s\n",
> acpi_power_state_string(state),
> - acpi_power_state_string(device->parent-
> >power.state));
> + acpi_power_state_string(parent->power.state));
> return -ENODEV;
> }
>
> Index: linux-pm/drivers/acpi/acpi_platform.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/acpi_platform.c
> +++ linux-pm/drivers/acpi/acpi_platform.c
> @@ -78,7 +78,7 @@ static void acpi_platform_fill_resource(
> * If the device has parent we need to take its resources into
> * account as well because this device might consume part of those.
> */
> - parent = acpi_get_first_physical_node(adev->parent);
> + parent = acpi_get_first_physical_node(acpi_dev_parent(adev));
> if (parent && dev_is_pci(parent))
> dest->parent = pci_find_resource(to_pci_dev(parent), dest);
> }
> @@ -97,6 +97,7 @@ static void acpi_platform_fill_resource(
> struct platform_device *acpi_create_platform_device(struct acpi_device *adev,
> const struct property_entry
> *properties)
> {
> + struct acpi_device *parent = acpi_dev_parent(adev);
> struct platform_device *pdev = NULL;
> struct platform_device_info pdevinfo;
> struct resource_entry *rentry;
> @@ -137,8 +138,7 @@ struct platform_device *acpi_create_plat
> * attached to it, that physical device should be the parent of the
> * platform device we are about to create.
> */
> - pdevinfo.parent = adev->parent ?
> - acpi_get_first_physical_node(adev->parent) : NULL;
> + pdevinfo.parent = parent ? acpi_get_first_physical_node(parent) : NULL;
> pdevinfo.name = dev_name(&adev->dev);
> pdevinfo.id = -1;
> pdevinfo.res = resources;
> Index: linux-pm/drivers/acpi/acpi_video.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/acpi_video.c
> +++ linux-pm/drivers/acpi/acpi_video.c
> @@ -2030,7 +2030,7 @@ static int acpi_video_bus_add(struct acp
> acpi_status status;
>
> status = acpi_walk_namespace(ACPI_TYPE_DEVICE,
> - device->parent->handle, 1,
> + acpi_dev_parent(device)->handle, 1,
> acpi_video_bus_match, NULL,
> device, NULL);
> if (status == AE_ALREADY_EXISTS) {
> Index: linux-pm/drivers/acpi/sbs.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/sbs.c
> +++ linux-pm/drivers/acpi/sbs.c
> @@ -632,7 +632,7 @@ static int acpi_sbs_add(struct acpi_devi
>
> mutex_init(&sbs->lock);
>
> - sbs->hc = acpi_driver_data(device->parent);
> + sbs->hc = acpi_driver_data(acpi_dev_parent(device));
> sbs->device = device;
> strcpy(acpi_device_name(device), ACPI_SBS_DEVICE_NAME);
> strcpy(acpi_device_class(device), ACPI_SBS_CLASS);
> Index: linux-pm/drivers/acpi/sbshc.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/sbshc.c
> +++ linux-pm/drivers/acpi/sbshc.c
> @@ -266,7 +266,7 @@ static int acpi_smbus_hc_add(struct acpi
> mutex_init(&hc->lock);
> init_waitqueue_head(&hc->wait);
>
> - hc->ec = acpi_driver_data(device->parent);
> + hc->ec = acpi_driver_data(acpi_dev_parent(device));
> hc->offset = (val >> 8) & 0xff;
> hc->query_bit = val & 0xff;
> device->driver_data = hc;
> Index: linux-pm/drivers/spi/spi.c
> ===================================================================
> --- linux-pm.orig/drivers/spi/spi.c
> +++ linux-pm/drivers/spi/spi.c
> @@ -4375,7 +4375,7 @@ static int acpi_spi_notify(struct notifi
>
> switch (value) {
> case ACPI_RECONFIG_DEVICE_ADD:
> - ctlr = acpi_spi_find_controller_by_adev(adev->parent);
> + ctlr = acpi_spi_find_controller_by_adev(acpi_dev_parent(adev));
> if (!ctlr)
> break;
>
> Index: linux-pm/drivers/thunderbolt/acpi.c
> ===================================================================
> --- linux-pm.orig/drivers/thunderbolt/acpi.c
> +++ linux-pm/drivers/thunderbolt/acpi.c
> @@ -42,7 +42,7 @@ static acpi_status tb_acpi_add_link(acpi
> */
> dev = acpi_get_first_physical_node(adev);
> while (!dev) {
> - adev = adev->parent;
> + adev = acpi_dev_parent(adev);
> if (!adev)
> break;
> dev = acpi_get_first_physical_node(adev);
> Index: linux-pm/drivers/hv/vmbus_drv.c
> ===================================================================
> --- linux-pm.orig/drivers/hv/vmbus_drv.c
> +++ linux-pm/drivers/hv/vmbus_drv.c
> @@ -2427,7 +2427,8 @@ static int vmbus_acpi_add(struct acpi_de
> * Some ancestor of the vmbus acpi device (Gen1 or Gen2
> * firmware) is the VMOD that has the mmio ranges. Get that.
> */
> - for (ancestor = device->parent; ancestor; ancestor = ancestor->parent) {
> + for (ancestor = acpi_dev_parent(device); ancestor;
> + ancestor = acpi_dev_parent(ancestor)) {
> result = acpi_walk_resources(ancestor->handle, METHOD_NAME__CRS,
> vmbus_walk_resources, NULL);
>
> Index: linux-pm/drivers/acpi/acpi_amba.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/acpi_amba.c
> +++ linux-pm/drivers/acpi/acpi_amba.c
> @@ -48,6 +48,7 @@ static void amba_register_dummy_clk(void
> static int amba_handler_attach(struct acpi_device *adev,
> const struct acpi_device_id *id)
> {
> + struct acpi_device *parent = acpi_dev_parent(adev);
> struct amba_device *dev;
> struct resource_entry *rentry;
> struct list_head resource_list;
> @@ -97,8 +98,8 @@ static int amba_handler_attach(struct ac
> * attached to it, that physical device should be the parent of
> * the amba device we are about to create.
> */
> - if (adev->parent)
> - dev->dev.parent = acpi_get_first_physical_node(adev->parent);
> + if (parent)
> + dev->dev.parent = acpi_get_first_physical_node(parent);
>
> ACPI_COMPANION_SET(&dev->dev, adev);
>
> Index: linux-pm/drivers/perf/arm_dsu_pmu.c
> ===================================================================
> --- linux-pm.orig/drivers/perf/arm_dsu_pmu.c
> +++ linux-pm/drivers/perf/arm_dsu_pmu.c
> @@ -639,6 +639,7 @@ static int dsu_pmu_dt_get_cpus(struct de
> static int dsu_pmu_acpi_get_cpus(struct device *dev, cpumask_t *mask)
> {
> #ifdef CONFIG_ACPI
> + struct acpi_device *parent_adev = acpi_dev_parent(ACPI_COMPANION(dev));
> int cpu;
>
> /*
> @@ -653,8 +654,7 @@ static int dsu_pmu_acpi_get_cpus(struct
> continue;
>
> acpi_dev = ACPI_COMPANION(cpu_dev);
> - if (acpi_dev &&
> - acpi_dev->parent == ACPI_COMPANION(dev)->parent)
> + if (acpi_dev && acpi_dev_parent(acpi_dev) == parent_adev)
> cpumask_set_cpu(cpu, mask);
> }
> #endif
> Index: linux-pm/drivers/perf/qcom_l3_pmu.c
> ===================================================================
> --- linux-pm.orig/drivers/perf/qcom_l3_pmu.c
> +++ linux-pm/drivers/perf/qcom_l3_pmu.c
> @@ -742,7 +742,8 @@ static int qcom_l3_cache_pmu_probe(struc
>
> l3pmu = devm_kzalloc(&pdev->dev, sizeof(*l3pmu), GFP_KERNEL);
> name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "l3cache_%s_%s",
> - acpi_dev->parent->pnp.unique_id, acpi_dev->pnp.unique_id);
> + acpi_dev_parent(acpi_dev)->pnp.unique_id,
> + acpi_dev->pnp.unique_id);
> if (!l3pmu || !name)
> return -ENOMEM;
>
>
>
